PMC:7464876 / 35297-36858
Annnotations
{"target":"http://pubannotation.org/docs/sourcedb/PMC/sourceid/7464876","sourcedb":"PMC","sourceid":"7464876","source_url":"https://www.ncbi.nlm.nih.gov/pmc/7464876","text":"Given the important role of Sec24A in guiding ERGIC-53 ER export and its involvement in HBV subviral and viral envelope trafficking, we next investigated whether ERGIC-53 may likewise contribute to HBV spherical SVP secretion. For this, we employed an SVP release assay and transiently transfected HuH-7 cells with an expression construct encoding only the S envelope gene (HBV.S) with a C-terminally fused HA-tag and examined the intra- and extracellular HBV.S levels by HA-specific WB. For RNAi, cells were treated with control or ERGIC-53-specific RNA duplexes (72 h) prior to transfection with HBV.S (48 h). To control the accuracy of the SVP release assay, cells were depleted for Sec24A, an intervention known to block SVP secretion [29]. Lysates and supernatants were harvested, and SVPs present in the supernatants were collected by ultracentrifugation through sucrose cushions. Immunoblotting of lysates with anti-ERGIC-53 and anti-Sec24A antibodies demonstrated efficient depletions without any signs of codepletions (Figure 5C). Consistent with our previous results [29], Sec24A silencing strongly inhibited the secretion of HBV.S as compared to the control cells and concomitantly increased the intracellular S.HA levels (Figure 5C). In contrast, the KD of ERGIC-53 neither interfered with the synthesis of the nonglycosylated and glycosylated HBV.S forms nor with their secretion (Figure 5C). Together, these data indicate that the export routes for HBV viral and spherical subviral particles dramatically differ in their requirements for ERGIC-53.","tracks":[{"project":"2_test","denotations":[{"id":"32806600-32017353-20296222","span":{"begin":740,"end":742},"obj":"32017353"},{"id":"32806600-32017353-20296223","span":{"begin":1078,"end":1080},"obj":"32017353"}],"attributes":[{"subj":"32806600-32017353-20296222","pred":"source","obj":"2_test"},{"subj":"32806600-32017353-20296223","pred":"source","obj":"2_test"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"2_test","color":"#aa93ec","default":true}]}]}}