PMC:4504005 / 23890-25018 JSONTXT

{"project":"TEST0","denotations":[{"id":"25982113-149-157-8319028","span":{"begin":149,"end":153},"obj":"[\"17785463\", \"17785463\", \"17785463\"]"},{"id":"25982113-173-181-8319029","span":{"begin":173,"end":177},"obj":"[\"23247088\", \"23247088\", \"23247088\"]"},{"id":"25982113-194-202-8319030","span":{"begin":194,"end":198},"obj":"[\"22102369\", \"22102369\", \"22102369\"]"},{"id":"25982113-218-226-8319031","span":{"begin":218,"end":222},"obj":"[\"24115156\", \"24115156\", \"24115156\"]"},{"id":"25982113-230-238-8319033","span":{"begin":807,"end":811},"obj":"[\"24115156\", \"24115156\", \"24115156\"]"},{"id":"25982113-15-23-8319034","span":{"begin":829,"end":833},"obj":"[\"17785463\", \"17785463\", \"17785463\"]"}],"text":"The oligomeric states of CLR:RAMP complexes has been a source of debate with evidence for 1:1, 2:1, and 2:2 CLR:RAMP stoichiometries (Héroux et al., 2007; Hill and Pioszak, 2013; Kusano et al., 2012; Moad and Pioszak, 2013; Watkins et al., 2013a). Dimerization of the purified CLR:RAMP2 ECD heterodimer to form a 2:2 complex may be an artifact because the RAMP2 L106R mutation prevented oligomerization yet did not affect AM1 receptor function (Figure S1). Occlusion of the AM-binding site by dimerization explains our inability to measure AM binding to the tethered RAMP2-CLR ECD fusion protein in an assay using μM receptor concentration, whereas AM binding was readily measured in an assay using nM receptor concentration where the dimeric species was likely not significantly present (Moad and Pioszak, 2013). Héroux et al. (2007) provided evidence for a homo-oligomer of CLR with a single RAMP1 as the functional CGRP receptor in cells. We cannot rule out a role for higher-order oligomerization in the function of the intact receptors, but the structures indicate that the 1:1 heterodimers are sufficient to bind peptides."}

{"project":"2_test","denotations":[{"id":"25982113-17785463-118216129","span":{"begin":149,"end":153},"obj":"17785463"},{"id":"25982113-17785463-118216129","span":{"begin":149,"end":153},"obj":"17785463"},{"id":"25982113-23247088-118216130","span":{"begin":173,"end":177},"obj":"23247088"},{"id":"25982113-23247088-118216130","span":{"begin":173,"end":177},"obj":"23247088"},{"id":"25982113-22102369-118216131","span":{"begin":194,"end":198},"obj":"22102369"},{"id":"25982113-22102369-118216131","span":{"begin":194,"end":198},"obj":"22102369"},{"id":"25982113-24115156-118216132","span":{"begin":218,"end":222},"obj":"24115156"},{"id":"25982113-24115156-118216132","span":{"begin":218,"end":222},"obj":"24115156"},{"id":"25982113-24115156-118216134","span":{"begin":807,"end":811},"obj":"24115156"},{"id":"25982113-24115156-118216134","span":{"begin":807,"end":811},"obj":"24115156"},{"id":"25982113-17785463-118216135","span":{"begin":829,"end":833},"obj":"17785463"},{"id":"25982113-17785463-118216135","span":{"begin":829,"end":833},"obj":"17785463"},{"id":"25982113-24115156-71076124","span":{"begin":807,"end":811},"obj":"24115156"},{"id":"25982113-24115156-71076124","span":{"begin":807,"end":811},"obj":"24115156"},{"id":"25982113-17785463-71076125","span":{"begin":829,"end":833},"obj":"17785463"},{"id":"25982113-17785463-71076125","span":{"begin":829,"end":833},"obj":"17785463"}],"text":"The oligomeric states of CLR:RAMP complexes has been a source of debate with evidence for 1:1, 2:1, and 2:2 CLR:RAMP stoichiometries (Héroux et al., 2007; Hill and Pioszak, 2013; Kusano et al., 2012; Moad and Pioszak, 2013; Watkins et al., 2013a). Dimerization of the purified CLR:RAMP2 ECD heterodimer to form a 2:2 complex may be an artifact because the RAMP2 L106R mutation prevented oligomerization yet did not affect AM1 receptor function (Figure S1). Occlusion of the AM-binding site by dimerization explains our inability to measure AM binding to the tethered RAMP2-CLR ECD fusion protein in an assay using μM receptor concentration, whereas AM binding was readily measured in an assay using nM receptor concentration where the dimeric species was likely not significantly present (Moad and Pioszak, 2013). Héroux et al. (2007) provided evidence for a homo-oligomer of CLR with a single RAMP1 as the functional CGRP receptor in cells. We cannot rule out a role for higher-order oligomerization in the function of the intact receptors, but the structures indicate that the 1:1 heterodimers are sufficient to bind peptides."}