Doc2b serves as a scaffolding platform for concurrent binding of multiple Munc18 isoforms in pancreatic islet β-cells
dc.contributor.author | Ramalingam, Latha | |
dc.contributor.author | Lu, Jingping | |
dc.contributor.author | Hudmon, Andy | |
dc.contributor.author | Thurmond, Debbie C. | |
dc.contributor.department | Department of Biochemistry & Molecular Biology, IU School of Medicine | en_US |
dc.date.accessioned | 2016-02-26T17:32:30Z | |
dc.date.available | 2016-02-26T17:32:30Z | |
dc.date.issued | 2014-12 | |
dc.description.abstract | Biphasic glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells involves soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor (SNARE) protein-regulated exocytosis. SNARE complex assembly further requires the regulatory proteins Munc18c, Munc18-1 and Doc2b. Munc18-1 and Munc18c are required for first- and second-phase GSIS respectively. These distinct Munc18-1 and Munc18c roles are related to their transient high-affinity binding with their cognate target (t-)SNAREs, Syntaxin 1A and Syntaxin 4 respectively. Doc2b is essential for both phases of GSIS, yet the molecular basis for this remains unresolved. Because Doc2b binds to Munc18-1 and Munc18c via its distinct C2A and C2B domains respectively, we hypothesized that Doc2b may provide a plasma membrane-localized scaffold/platform for transient docking of these Munc18 isoforms during GSIS. Towards this, macromolecular complexes composed of Munc18c, Doc2b and Munc18-1 were detected in β-cells. In vitro interaction assays indicated that Doc2b is required to bridge the interaction between Munc18c and Munc18-1 in the macromolecular complex; Munc18c and Munc18-1 failed to associate in the absence of Doc2b. Competition-based GST-Doc2b interaction assays revealed that Doc2b could simultaneously bind both Munc18-1 and Munc18c. Hence these data support a working model wherein Doc2b functions as a docking platform/scaffold for transient interactions with the multiple Munc18 isoforms operative in insulin release, promoting SNARE assembly. | en_US |
dc.eprint.version | Author's manuscript | en_US |
dc.identifier.citation | Ramalingam, L., Lu, J., Hudmon, A., & Thurmond, D. C. (2014). Doc2b Serves as a Scaffolding Platform for Concurrent Binding of Multiple Munc18 Isoforms in Pancreatic Islet Beta Cells. The Biochemical Journal, 464(2), 251–258. http://doi.org/10.1042/BJ20140845 | en_US |
dc.identifier.uri | https://hdl.handle.net/1805/8533 | |
dc.language.iso | en_US | en_US |
dc.publisher | Portland Press | en_US |
dc.relation.isversionof | 10.1042/BJ20140845 | en_US |
dc.relation.journal | Biochemical Journal | en_US |
dc.rights | Publisher Policy | en_US |
dc.source | PMC | en_US |
dc.subject | SNARE protein | en_US |
dc.subject | Munc18c | en_US |
dc.subject | Munc18-1 | en_US |
dc.subject | Insulin exocytosis | en_US |
dc.subject | Islet beta cells | en_US |
dc.subject | Doc2b | en_US |
dc.title | Doc2b serves as a scaffolding platform for concurrent binding of multiple Munc18 isoforms in pancreatic islet β-cells | en_US |
dc.type | Article | en_US |