Dual Role of BAR Domain-containing Proteins in Regulating Vesicle Release Catalyzed by the GTPase, Dynamin-2

• Published in: The Journal of biological chemistry Vol. 288; no. 35; pp. 25119 - 25128
• Main Authors: Neumann, Sylvia, Schmid, Sandra L.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30.08.2013; American Society for Biochemistry and Molecular Biology
• Subjects: BAR Domain; Catalysis; Cell Membrane - chemistry; Cell Membrane - genetics; Cell Membrane - metabolism; Dynamin; Dynamin II - chemistry; Dynamin II - genetics; Dynamin II - metabolism; Endocytosis; Endocytosis - physiology; ENTH Domain; Humans; Membrane Biology; Membrane Curvature; Membrane Fission; Membrane Trafficking; Membrane Transport; Molecular Cell Biology; Nerve Tissue Proteins - chemistry; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; src Homology Domains; Vesicles; Membrane Trafficking; Endocytosis; Vesicles; Membrane Fission; Molecular Cell Biology; Membrane Transport; Dynamin; ENTH Domain; Membrane Curvature; BAR Domain
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M113.490474

Dynamin-2 (Dyn2) is ubiquitously expressed and catalyzes membrane fission during clathrin-mediated endocytosis in nonneuronal cells. We have previously shown that Dyn2 inefficiently generates membrane curvature and only mediates fission of highly curved membranes. This led to the hypothesis that other endocytic accessory proteins (EAPs) generate curvature needed to sculpt a sufficiently narrow neck to trigger Dyn2 assembly and fission. Candidates for this activity are EAPs that bind to the dynamin proline/arginine-rich domain (PRD) through their SH3 (src homology-3) domains and also encode curvature-generating BAR (Bin/Amphiphysin/Rvs) domains. We show that at low concentrations, amphiphysin and endophilin, but not SNX9 or the curvature-generating epsin N-terminal homology (ENTH) domain, are able to generate tubules from planar membrane templates and to synergize with Dyn2ΔPRD to catalyze vesicle release. Unexpectedly, SH3-PRD interactions were inhibitory and reciprocally regulate scaffold assembly. Of the three proteins studied, only full-length amphiphysin functions synergistically with full-length Dyn2 to catalyze vesicle release. The differential activity of these proteins correlates with the relative potency of their positive, curvature-generating activity, and the negative regulatory effects mediated by SH3 domain interactions. Our findings reveal opportunities for the spatio-temporal coordination of membrane curvature generation, dynamin assembly, and fission during clathrin-mediated endocytosis. Background: Membrane curvature generation is essential for dynamin-2-catalyzed membrane fission and vesicle release. Results: Dynamin-2 binding partners with curvature generating activity differentially regulate the assembly, GTPase, and fission activities of dynamin-2. Conclusion: Dynamin-2 partners display complex patterns of regulation. Significance: The distinct functional interactions between dynamin-2 and its binding partners position them to contribute to the spatio-temporal regulation of clathrin-mediated endocytosis.