PMC:7352545 / 55060-57846 JSONTXT

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    LitCovid_Glycan-Motif-Structure

    {"project":"LitCovid_Glycan-Motif-Structure","denotations":[{"id":"T193","span":{"begin":765,"end":774},"obj":"https://glytoucan.org/Structures/Glycans/G65889KE"},{"id":"T194","span":{"begin":765,"end":774},"obj":"https://glytoucan.org/Structures/Glycans/G68158BT"},{"id":"T195","span":{"begin":1552,"end":1554},"obj":"https://glytoucan.org/Structures/Glycans/G81533KY"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    LitCovid-PD-FMA-UBERON

    {"project":"LitCovid-PD-FMA-UBERON","denotations":[{"id":"T476","span":{"begin":37,"end":42},"obj":"Body_part"},{"id":"T477","span":{"begin":62,"end":75},"obj":"Body_part"},{"id":"T478","span":{"begin":110,"end":117},"obj":"Body_part"},{"id":"T479","span":{"begin":159,"end":171},"obj":"Body_part"},{"id":"T480","span":{"begin":280,"end":284},"obj":"Body_part"},{"id":"T481","span":{"begin":372,"end":377},"obj":"Body_part"},{"id":"T482","span":{"begin":420,"end":427},"obj":"Body_part"},{"id":"T483","span":{"begin":561,"end":566},"obj":"Body_part"},{"id":"T484","span":{"begin":574,"end":578},"obj":"Body_part"},{"id":"T485","span":{"begin":765,"end":774},"obj":"Body_part"},{"id":"T486","span":{"begin":853,"end":858},"obj":"Body_part"},{"id":"T487","span":{"begin":886,"end":890},"obj":"Body_part"},{"id":"T488","span":{"begin":900,"end":907},"obj":"Body_part"},{"id":"T489","span":{"begin":909,"end":912},"obj":"Body_part"},{"id":"T490","span":{"begin":922,"end":926},"obj":"Body_part"},{"id":"T491","span":{"begin":1079,"end":1083},"obj":"Body_part"},{"id":"T492","span":{"begin":1107,"end":1119},"obj":"Body_part"},{"id":"T493","span":{"begin":1120,"end":1124},"obj":"Body_part"},{"id":"T494","span":{"begin":1140,"end":1147},"obj":"Body_part"},{"id":"T495","span":{"begin":1172,"end":1176},"obj":"Body_part"},{"id":"T496","span":{"begin":1208,"end":1213},"obj":"Body_part"},{"id":"T497","span":{"begin":1250,"end":1257},"obj":"Body_part"},{"id":"T498","span":{"begin":1563,"end":1571},"obj":"Body_part"},{"id":"T499","span":{"begin":1629,"end":1634},"obj":"Body_part"},{"id":"T500","span":{"begin":1693,"end":1706},"obj":"Body_part"},{"id":"T501","span":{"begin":1693,"end":1697},"obj":"Body_part"},{"id":"T502","span":{"begin":1872,"end":1880},"obj":"Body_part"},{"id":"T503","span":{"begin":1986,"end":1998},"obj":"Body_part"},{"id":"T504","span":{"begin":2130,"end":2136},"obj":"Body_part"},{"id":"T505","span":{"begin":2305,"end":2318},"obj":"Body_part"},{"id":"T506","span":{"begin":2368,"end":2380},"obj":"Body_part"},{"id":"T507","span":{"begin":2570,"end":2578},"obj":"Body_part"},{"id":"T508","span":{"begin":2667,"end":2672},"obj":"Body_part"}],"attributes":[{"id":"A476","pred":"fma_id","subj":"T476","obj":"http://purl.org/sig/ont/fma/fma68646"},{"id":"A477","pred":"fma_id","subj":"T477","obj":"http://purl.org/sig/ont/fma/fma62925"},{"id":"A478","pred":"fma_id","subj":"T478","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A479","pred":"fma_id","subj":"T479","obj":"http://purl.org/sig/ont/fma/fma62925"},{"id":"A480","pred":"fma_id","subj":"T480","obj":"http://purl.org/sig/ont/fma/fma68646"},{"id":"A481","pred":"fma_id","subj":"T481","obj":"http://purl.org/sig/ont/fma/fma67264"},{"id":"A482","pred":"fma_id","subj":"T482","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A483","pred":"fma_id","subj":"T483","obj":"http://purl.org/sig/ont/fma/fma68646"},{"id":"A484","pred":"fma_id","subj":"T484","obj":"http://purl.org/sig/ont/fma/fma68646"},{"id":"A485","pred":"fma_id","subj":"T485","obj":"http://purl.org/sig/ont/fma/fma82794"},{"id":"A486","pred":"fma_id","subj":"T486","obj":"http://purl.org/sig/ont/fma/fma82737"},{"id":"A487","pred":"fma_id","subj":"T487","obj":"http://purl.org/sig/ont/fma/fma68646"},{"id":"A488","pred":"fma_id","subj":"T488","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A489","pred":"fma_id","subj":"T489","obj":"http://purl.org/sig/ont/fma/fma67214"},{"id":"A490","pred":"fma_id","subj":"T490","obj":"http://purl.org/sig/ont/fma/fma67122"},{"id":"A491","pred":"fma_id","subj":"T491","obj":"http://purl.org/sig/ont/fma/fma74402"},{"id":"A492","pred":"fma_id","subj":"T492","obj":"http://purl.org/sig/ont/fma/fma62925"},{"id":"A493","pred":"fma_id","subj":"T493","obj":"http://purl.org/sig/ont/fma/fma74402"},{"id":"A494","pred":"fma_id","subj":"T494","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A495","pred":"fma_id","subj":"T495","obj":"http://purl.org/sig/ont/fma/fma74402"},{"id":"A496","pred":"fma_id","subj":"T496","obj":"http://purl.org/sig/ont/fma/fma82737"},{"id":"A497","pred":"fma_id","subj":"T497","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A498","pred":"fma_id","subj":"T498","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A499","pred":"fma_id","subj":"T499","obj":"http://purl.org/sig/ont/fma/fma68646"},{"id":"A500","pred":"fma_id","subj":"T500","obj":"http://purl.org/sig/ont/fma/fma63841"},{"id":"A501","pred":"fma_id","subj":"T501","obj":"http://purl.org/sig/ont/fma/fma68646"},{"id":"A502","pred":"fma_id","subj":"T502","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A503","pred":"fma_id","subj":"T503","obj":"http://purl.org/sig/ont/fma/fma62925"},{"id":"A504","pred":"fma_id","subj":"T504","obj":"http://purl.org/sig/ont/fma/fma9637"},{"id":"A505","pred":"fma_id","subj":"T505","obj":"http://purl.org/sig/ont/fma/fma62925"},{"id":"A506","pred":"fma_id","subj":"T506","obj":"http://purl.org/sig/ont/fma/fma62925"},{"id":"A507","pred":"fma_id","subj":"T507","obj":"http://purl.org/sig/ont/fma/fma67257"},{"id":"A508","pred":"fma_id","subj":"T508","obj":"http://purl.org/sig/ont/fma/fma68646"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    LitCovid-PD-UBERON

    {"project":"LitCovid-PD-UBERON","denotations":[{"id":"T28","span":{"begin":2130,"end":2136},"obj":"Body_part"}],"attributes":[{"id":"A28","pred":"uberon_id","subj":"T28","obj":"http://purl.obolibrary.org/obo/UBERON_0000479"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    LitCovid-PD-MONDO

    {"project":"LitCovid-PD-MONDO","denotations":[{"id":"T221","span":{"begin":593,"end":596},"obj":"Disease"},{"id":"T223","span":{"begin":719,"end":722},"obj":"Disease"},{"id":"T225","span":{"begin":805,"end":808},"obj":"Disease"},{"id":"T227","span":{"begin":843,"end":846},"obj":"Disease"},{"id":"T229","span":{"begin":1505,"end":1515},"obj":"Disease"},{"id":"T230","span":{"begin":2224,"end":2233},"obj":"Disease"}],"attributes":[{"id":"A221","pred":"mondo_id","subj":"T221","obj":"http://purl.obolibrary.org/obo/MONDO_0008449"},{"id":"A222","pred":"mondo_id","subj":"T221","obj":"http://purl.obolibrary.org/obo/MONDO_0018075"},{"id":"A223","pred":"mondo_id","subj":"T223","obj":"http://purl.obolibrary.org/obo/MONDO_0008449"},{"id":"A224","pred":"mondo_id","subj":"T223","obj":"http://purl.obolibrary.org/obo/MONDO_0018075"},{"id":"A225","pred":"mondo_id","subj":"T225","obj":"http://purl.obolibrary.org/obo/MONDO_0008449"},{"id":"A226","pred":"mondo_id","subj":"T225","obj":"http://purl.obolibrary.org/obo/MONDO_0018075"},{"id":"A227","pred":"mondo_id","subj":"T227","obj":"http://purl.obolibrary.org/obo/MONDO_0008449"},{"id":"A228","pred":"mondo_id","subj":"T227","obj":"http://purl.obolibrary.org/obo/MONDO_0018075"},{"id":"A229","pred":"mondo_id","subj":"T229","obj":"http://purl.obolibrary.org/obo/MONDO_0005550"},{"id":"A230","pred":"mondo_id","subj":"T230","obj":"http://purl.obolibrary.org/obo/MONDO_0005550"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    LitCovid-PD-CLO

    {"project":"LitCovid-PD-CLO","denotations":[{"id":"T776","span":{"begin":37,"end":42},"obj":"http://purl.obolibrary.org/obo/GO_0005623"},{"id":"T777","span":{"begin":127,"end":135},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T778","span":{"begin":184,"end":186},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T779","span":{"begin":196,"end":201},"obj":"http://purl.obolibrary.org/obo/UBERON_0000033"},{"id":"T780","span":{"begin":196,"end":201},"obj":"http://www.ebi.ac.uk/efo/EFO_0000964"},{"id":"T781","span":{"begin":213,"end":215},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T782","span":{"begin":216,"end":221},"obj":"http://purl.obolibrary.org/obo/UBERON_0000033"},{"id":"T783","span":{"begin":216,"end":221},"obj":"http://www.ebi.ac.uk/efo/EFO_0000964"},{"id":"T784","span":{"begin":229,"end":234},"obj":"http://purl.obolibrary.org/obo/NCBITaxon_10239"},{"id":"T785","span":{"begin":280,"end":284},"obj":"http://purl.obolibrary.org/obo/GO_0005623"},{"id":"T786","span":{"begin":324,"end":332},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T787","span":{"begin":474,"end":482},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T788","span":{"begin":561,"end":566},"obj":"http://purl.obolibrary.org/obo/GO_0005623"},{"id":"T789","span":{"begin":574,"end":578},"obj":"http://purl.obolibrary.org/obo/GO_0005623"},{"id":"T790","span":{"begin":600,"end":602},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T791","span":{"begin":690,"end":695},"obj":"http://purl.obolibrary.org/obo/NCBITaxon_10239"},{"id":"T792","span":{"begin":716,"end":718},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T793","span":{"begin":723,"end":726},"obj":"http://purl.obolibrary.org/obo/CLO_0051582"},{"id":"T794","span":{"begin":727,"end":728},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T795","span":{"begin":759,"end":764},"obj":"http://purl.obolibrary.org/obo/NCBITaxon_9606"},{"id":"T796","span":{"begin":802,"end":804},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T797","span":{"begin":840,"end":842},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T798","span":{"begin":884,"end":890},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T799","span":{"begin":1079,"end":1083},"obj":"http://purl.obolibrary.org/obo/OGG_0000000002"},{"id":"T800","span":{"begin":1104,"end":1106},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T801","span":{"begin":1120,"end":1124},"obj":"http://purl.obolibrary.org/obo/OGG_0000000002"},{"id":"T802","span":{"begin":1137,"end":1139},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T803","span":{"begin":1172,"end":1176},"obj":"http://purl.obolibrary.org/obo/OGG_0000000002"},{"id":"T804","span":{"begin":1247,"end":1249},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T805","span":{"begin":1315,"end":1323},"obj":"http://purl.obolibrary.org/obo/CLO_0001658"},{"id":"T806","span":{"begin":1325,"end":1328},"obj":"http://purl.obolibrary.org/obo/CLO_0054060"},{"id":"T807","span":{"begin":1602,"end":1610},"obj":"http://purl.obolibrary.org/obo/CLO_0001658"},{"id":"T808","span":{"begin":1629,"end":1634},"obj":"http://purl.obolibrary.org/obo/GO_0005623"},{"id":"T809","span":{"begin":1687,"end":1692},"obj":"http://purl.obolibrary.org/obo/NCBITaxon_10239"},{"id":"T810","span":{"begin":1693,"end":1697},"obj":"http://purl.obolibrary.org/obo/GO_0005623"},{"id":"T811","span":{"begin":1698,"end":1706},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T812","span":{"begin":2038,"end":2046},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T813","span":{"begin":2390,"end":2398},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T814","span":{"begin":2463,"end":2465},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T815","span":{"begin":2497,"end":2499},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T816","span":{"begin":2500,"end":2502},"obj":"http://purl.obolibrary.org/obo/CLO_0008922"},{"id":"T817","span":{"begin":2500,"end":2502},"obj":"http://purl.obolibrary.org/obo/CLO_0050052"},{"id":"T818","span":{"begin":2535,"end":2537},"obj":"http://purl.obolibrary.org/obo/CLO_0050050"},{"id":"T819","span":{"begin":2613,"end":2621},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T820","span":{"begin":2655,"end":2662},"obj":"http://purl.obolibrary.org/obo/NCBITaxon_10239"},{"id":"T821","span":{"begin":2667,"end":2672},"obj":"http://purl.obolibrary.org/obo/GO_0005623"},{"id":"T822","span":{"begin":2695,"end":2703},"obj":"http://purl.obolibrary.org/obo/PR_000018263"},{"id":"T823","span":{"begin":2711,"end":2713},"obj":"http://purl.obolibrary.org/obo/CLO_0008922"},{"id":"T824","span":{"begin":2711,"end":2713},"obj":"http://purl.obolibrary.org/obo/CLO_0050052"},{"id":"T825","span":{"begin":2738,"end":2747},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"},{"id":"T826","span":{"begin":2752,"end":2760},"obj":"http://purl.obolibrary.org/obo/UBERON_0000158"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    LitCovid-PD-CHEBI

    {"project":"LitCovid-PD-CHEBI","denotations":[{"id":"T125","span":{"begin":62,"end":75},"obj":"Chemical"},{"id":"T81226","span":{"begin":110,"end":117},"obj":"Chemical"},{"id":"T99806","span":{"begin":159,"end":171},"obj":"Chemical"},{"id":"T128","span":{"begin":258,"end":267},"obj":"Chemical"},{"id":"T86776","span":{"begin":286,"end":297},"obj":"Chemical"},{"id":"T46368","span":{"begin":372,"end":377},"obj":"Chemical"},{"id":"T37044","span":{"begin":420,"end":427},"obj":"Chemical"},{"id":"T11862","span":{"begin":540,"end":551},"obj":"Chemical"},{"id":"T50236","span":{"begin":765,"end":774},"obj":"Chemical"},{"id":"T134","span":{"begin":900,"end":907},"obj":"Chemical"},{"id":"T39590","span":{"begin":962,"end":964},"obj":"Chemical"},{"id":"T136","span":{"begin":1107,"end":1119},"obj":"Chemical"},{"id":"T137","span":{"begin":1140,"end":1147},"obj":"Chemical"},{"id":"T138","span":{"begin":1250,"end":1257},"obj":"Chemical"},{"id":"T139","span":{"begin":1552,"end":1554},"obj":"Chemical"},{"id":"T144","span":{"begin":1563,"end":1571},"obj":"Chemical"},{"id":"T145","span":{"begin":1810,"end":1813},"obj":"Chemical"},{"id":"T147","span":{"begin":1872,"end":1880},"obj":"Chemical"},{"id":"T13373","span":{"begin":1912,"end":1915},"obj":"Chemical"},{"id":"T78904","span":{"begin":1921,"end":1923},"obj":"Chemical"},{"id":"T82009","span":{"begin":1986,"end":1998},"obj":"Chemical"},{"id":"T45392","span":{"begin":2176,"end":2179},"obj":"Chemical"},{"id":"T53957","span":{"begin":2239,"end":2241},"obj":"Chemical"},{"id":"T23174","span":{"begin":2305,"end":2318},"obj":"Chemical"},{"id":"T158","span":{"begin":2368,"end":2380},"obj":"Chemical"},{"id":"T8007","span":{"begin":2500,"end":2502},"obj":"Chemical"},{"id":"T4434","span":{"begin":2570,"end":2578},"obj":"Chemical"},{"id":"T8852","span":{"begin":2695,"end":2703},"obj":"Chemical"},{"id":"T69566","span":{"begin":2711,"end":2713},"obj":"Chemical"}],"attributes":[{"id":"A51355","pred":"chebi_id","subj":"T125","obj":"http://purl.obolibrary.org/obo/CHEBI_17089"},{"id":"A54358","pred":"chebi_id","subj":"T81226","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A41450","pred":"chebi_id","subj":"T99806","obj":"http://purl.obolibrary.org/obo/CHEBI_17089"},{"id":"A37059","pred":"chebi_id","subj":"T128","obj":"http://purl.obolibrary.org/obo/CHEBI_25367"},{"id":"A80861","pred":"chebi_id","subj":"T86776","obj":"http://purl.obolibrary.org/obo/CHEBI_16113"},{"id":"A33658","pred":"chebi_id","subj":"T46368","obj":"http://purl.obolibrary.org/obo/CHEBI_18059"},{"id":"A72067","pred":"chebi_id","subj":"T37044","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A45637","pred":"chebi_id","subj":"T11862","obj":"http://purl.obolibrary.org/obo/CHEBI_16113"},{"id":"A64093","pred":"chebi_id","subj":"T50236","obj":"http://purl.obolibrary.org/obo/CHEBI_28260"},{"id":"A27467","pred":"chebi_id","subj":"T134","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A28211","pred":"chebi_id","subj":"T39590","obj":"http://purl.obolibrary.org/obo/CHEBI_73507"},{"id":"A66652","pred":"chebi_id","subj":"T136","obj":"http://purl.obolibrary.org/obo/CHEBI_17089"},{"id":"A17972","pred":"chebi_id","subj":"T137","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A45328","pred":"chebi_id","subj":"T138","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A25325","pred":"chebi_id","subj":"T139","obj":"http://purl.obolibrary.org/obo/CHEBI_35962"},{"id":"A30722","pred":"chebi_id","subj":"T139","obj":"http://purl.obolibrary.org/obo/CHEBI_38358"},{"id":"A81801","pred":"chebi_id","subj":"T139","obj":"http://purl.obolibrary.org/obo/CHEBI_45373"},{"id":"A32183","pred":"chebi_id","subj":"T139","obj":"http://purl.obolibrary.org/obo/CHEBI_74801"},{"id":"A89737","pred":"chebi_id","subj":"T139","obj":"http://purl.obolibrary.org/obo/CHEBI_26667"},{"id":"A68746","pred":"chebi_id","subj":"T144","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A10704","pred":"chebi_id","subj":"T145","obj":"http://purl.obolibrary.org/obo/CHEBI_36315"},{"id":"A10771","pred":"chebi_id","subj":"T145","obj":"http://purl.obolibrary.org/obo/CHEBI_59682"},{"id":"A52394","pred":"chebi_id","subj":"T147","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A76391","pred":"chebi_id","subj":"T13373","obj":"http://purl.obolibrary.org/obo/CHEBI_36315"},{"id":"A7206","pred":"chebi_id","subj":"T13373","obj":"http://purl.obolibrary.org/obo/CHEBI_59682"},{"id":"A65661","pred":"chebi_id","subj":"T78904","obj":"http://purl.obolibrary.org/obo/CHEBI_55460"},{"id":"A79162","pred":"chebi_id","subj":"T78904","obj":"http://purl.obolibrary.org/obo/CHEBI_74861"},{"id":"A69257","pred":"chebi_id","subj":"T82009","obj":"http://purl.obolibrary.org/obo/CHEBI_17089"},{"id":"A48022","pred":"chebi_id","subj":"T45392","obj":"http://purl.obolibrary.org/obo/CHEBI_36315"},{"id":"A80252","pred":"chebi_id","subj":"T45392","obj":"http://purl.obolibrary.org/obo/CHEBI_59682"},{"id":"A66264","pred":"chebi_id","subj":"T53957","obj":"http://purl.obolibrary.org/obo/CHEBI_55460"},{"id":"A80706","pred":"chebi_id","subj":"T53957","obj":"http://purl.obolibrary.org/obo/CHEBI_74861"},{"id":"A8761","pred":"chebi_id","subj":"T23174","obj":"http://purl.obolibrary.org/obo/CHEBI_17089"},{"id":"A26653","pred":"chebi_id","subj":"T158","obj":"http://purl.obolibrary.org/obo/CHEBI_17089"},{"id":"A7792","pred":"chebi_id","subj":"T8007","obj":"http://purl.obolibrary.org/obo/CHEBI_29387"},{"id":"A90204","pred":"chebi_id","subj":"T4434","obj":"http://purl.obolibrary.org/obo/CHEBI_36080"},{"id":"A16976","pred":"chebi_id","subj":"T8852","obj":"http://purl.obolibrary.org/obo/CHEBI_16670"},{"id":"A33038","pred":"chebi_id","subj":"T69566","obj":"http://purl.obolibrary.org/obo/CHEBI_29387"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    LitCovid-PD-GO-BP

    {"project":"LitCovid-PD-GO-BP","denotations":[{"id":"T87","span":{"begin":127,"end":142},"obj":"http://purl.obolibrary.org/obo/GO_0061025"},{"id":"T88","span":{"begin":324,"end":339},"obj":"http://purl.obolibrary.org/obo/GO_0061025"},{"id":"T89","span":{"begin":474,"end":489},"obj":"http://purl.obolibrary.org/obo/GO_0061025"},{"id":"T90","span":{"begin":886,"end":899},"obj":"http://purl.obolibrary.org/obo/GO_0007155"},{"id":"T91","span":{"begin":1615,"end":1628},"obj":"http://purl.obolibrary.org/obo/GO_0045087"},{"id":"T92","span":{"begin":1698,"end":1713},"obj":"http://purl.obolibrary.org/obo/GO_0061025"},{"id":"T93","span":{"begin":1721,"end":1730},"obj":"http://purl.obolibrary.org/obo/GO_0009058"},{"id":"T94","span":{"begin":2390,"end":2406},"obj":"http://purl.obolibrary.org/obo/GO_0061025"},{"id":"T95","span":{"begin":2613,"end":2628},"obj":"http://purl.obolibrary.org/obo/GO_0061025"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    LitCovid-sentences

    {"project":"LitCovid-sentences","denotations":[{"id":"T532","span":{"begin":0,"end":6},"obj":"Sentence"},{"id":"T533","span":{"begin":7,"end":22},"obj":"Sentence"},{"id":"T534","span":{"begin":23,"end":143},"obj":"Sentence"},{"id":"T535","span":{"begin":144,"end":202},"obj":"Sentence"},{"id":"T536","span":{"begin":203,"end":285},"obj":"Sentence"},{"id":"T537","span":{"begin":286,"end":495},"obj":"Sentence"},{"id":"T538","span":{"begin":496,"end":588},"obj":"Sentence"},{"id":"T539","span":{"begin":589,"end":622},"obj":"Sentence"},{"id":"T540","span":{"begin":623,"end":707},"obj":"Sentence"},{"id":"T541","span":{"begin":708,"end":797},"obj":"Sentence"},{"id":"T542","span":{"begin":798,"end":871},"obj":"Sentence"},{"id":"T543","span":{"begin":872,"end":952},"obj":"Sentence"},{"id":"T544","span":{"begin":953,"end":1029},"obj":"Sentence"},{"id":"T545","span":{"begin":1030,"end":1242},"obj":"Sentence"},{"id":"T546","span":{"begin":1243,"end":1330},"obj":"Sentence"},{"id":"T547","span":{"begin":1331,"end":1447},"obj":"Sentence"},{"id":"T548","span":{"begin":1448,"end":1635},"obj":"Sentence"},{"id":"T549","span":{"begin":1636,"end":1720},"obj":"Sentence"},{"id":"T550","span":{"begin":1721,"end":1881},"obj":"Sentence"},{"id":"T551","span":{"begin":1882,"end":2019},"obj":"Sentence"},{"id":"T552","span":{"begin":2020,"end":2087},"obj":"Sentence"},{"id":"T553","span":{"begin":2088,"end":2161},"obj":"Sentence"},{"id":"T554","span":{"begin":2162,"end":2413},"obj":"Sentence"},{"id":"T555","span":{"begin":2414,"end":2567},"obj":"Sentence"},{"id":"T556","span":{"begin":2568,"end":2629},"obj":"Sentence"},{"id":"T557","span":{"begin":2630,"end":2786},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}

    2_test

    {"project":"2_test","denotations":[{"id":"32604730-14990688-51944062","span":{"begin":491,"end":493},"obj":"14990688"},{"id":"32604730-28923942-51944063","span":{"begin":703,"end":705},"obj":"28923942"},{"id":"32604730-21670291-51944064","span":{"begin":860,"end":862},"obj":"21670291"},{"id":"32604730-26855426-51944065","span":{"begin":863,"end":865},"obj":"26855426"},{"id":"32604730-32150576-51944066","span":{"begin":1024,"end":1027},"obj":"32150576"},{"id":"32604730-27578435-51944067","span":{"begin":1442,"end":1445},"obj":"27578435"},{"id":"32604730-11773370-51944068","span":{"begin":2014,"end":2017},"obj":"11773370"},{"id":"32604730-11994468-51944069","span":{"begin":2156,"end":2159},"obj":"11994468"},{"id":"32604730-12414924-51944070","span":{"begin":2408,"end":2411},"obj":"12414924"},{"id":"32604730-7520090-51944071","span":{"begin":2477,"end":2480},"obj":"7520090"},{"id":"32604730-11222703-51944072","span":{"begin":2526,"end":2529},"obj":"11222703"},{"id":"T11901","span":{"begin":491,"end":493},"obj":"14990688"},{"id":"T94239","span":{"begin":703,"end":705},"obj":"28923942"},{"id":"T60974","span":{"begin":860,"end":862},"obj":"21670291"},{"id":"T40239","span":{"begin":863,"end":865},"obj":"26855426"},{"id":"T95315","span":{"begin":1024,"end":1027},"obj":"32150576"},{"id":"T82445","span":{"begin":1442,"end":1445},"obj":"27578435"},{"id":"T65492","span":{"begin":2014,"end":2017},"obj":"11773370"},{"id":"T46798","span":{"begin":2156,"end":2159},"obj":"11994468"},{"id":"T91956","span":{"begin":2408,"end":2411},"obj":"12414924"},{"id":"T88769","span":{"begin":2477,"end":2480},"obj":"7520090"},{"id":"T88164","span":{"begin":2526,"end":2529},"obj":"11222703"}],"text":"6.3.3. CEACAM Receptor\nEntry of host cells needs binding of S glycoproteins to the CEACAM receptor, forming S-protein-mediated membrane fusion. The trimeric S glycoprotein bears three S1 receptor heads. The three S1 heads of the virus bind to three receptor molecules on the host cell. Cholesterol is indirectly involved in membrane fusion through CEACAM engagement into “lipid raft” microdomains, increasing multiple S protein interaction with the receptors and triggering membrane fusion [97]. The enveloped CoV, MHV, binds to CEACAMs on cholesterol-depleted cells in BHK cell cultures. The NTD of S1 recognizes CEACAM1. For MERS-CoV, another CEACAM5 isoform is the attachment factor for virus entry [75]. The CoV S1 NTD has a similar tertiary structure to human galactose-recognizing galectins. MHV S1 NTD binds murine CEACAM1a and BCoV S1 NTD binds sugar [98,99,100]. CEACAM1a is a cell adhesion protein (CAM) and its mRNA is alternatively spliced. The cryo-EM structure of MHV S complexed with CEACAM1a was elucidated [101]. Thus, HCoVs evolutionarily combined the galectin gene of hosts into their S1 glycoprotein gene, while BCoV S1 protein is present without such gene recombination but contains the sugar-recognizing lectin capacity. MHV S1 protein also evolutionarily acquired murine CEACAM1a-recognizing activity [102]. Therefore, CoVs are under evolution to adapt their host receptor interaction to infect cross-species hosts [80,103]. On the host side, to escape the lethal pressure from CoV infections, hosts have also evolved to acquire SA-binding proteins such as siglecs to inhibit or activate the innate immune cells.\nBoth raft and non-raft CEACAMs are involved in the virus–cell membrane fusion event. Formation of CEACAM-associated MHV particles or CEACAM-induced MHV fusion is possible by GPI-anchored CEACAMs through the binding between CEACAM and S proteins. However, MHV can bind to both GPI- and TM-anchored CEACAMs. In addition, soluble CEACAMs also mediate S glycoprotein-driven fusion [104]. This implies that membrane anchors are not intrinsically necessary. In fact, CEACAMs are present in different tissue-specific isoforms [105]. Nevertheless, GPI-anchored CEACAMs are more effective for MHV infection than TM-anchored CEACAMs. Soluble CEACAM receptors can bind to viral S glycoproteins and induce conformational shifts to acceptable S glycoprotein-involved membrane fusions [106]. For example, soluble CEACAM forms interacts with S1 fragments [107] and alters the S1–S2 association stability [108] and S1 oxidation confirmation [109]. S proteins are structurally shifted prior to membrane fusion. For the cross-linking of viruses and cells, integral hydrophobic peptides of the S2 chain are embedded into membranes via membrane hydrophobic cholesterols."}