| First Author | Kimura T | Year | 2008 |
| Journal | J Cell Sci | Volume | 121 |
| Issue | Pt 18 | Pages | 3092-8 |
| PubMed ID | 18768935 | Mgi Jnum | J:139663 |
| Mgi Id | MGI:3809343 | Doi | 10.1242/jcs.030544 |
| Citation | Kimura T, et al. (2008) The GDP-dependent Rab27a effector coronin 3 controls endocytosis of secretory membrane in insulin-secreting cell lines. J Cell Sci 121(Pt 18):3092-8 |
| abstractText | Rab27a is involved in the control of membrane traffic, a crucial step in the regulated secretion. Typically, the guanosine triphosphate (GTP)-bound form has been considered to be active and, therefore, searching for proteins binding to the GTP-form has been attempted to look for their effectors. Here, we have identified the actin-bundling protein coronin 3 as a novel Rab27a effector that paradoxically bound guanosine diphosphate (GDP)-Rab27a in the pancreatic beta-cell line MIN6. Coronin 3 directly bound GDP-Rab27a through its beta-propeller structure. The most important insulin secretagogue glucose promptly shifted Rab27a from the GTP- to GDP-bound form. Knockdown of coronin 3 by RNAi resulted in the inhibition of phogrin (an insulin-granule-associated protein) internalization and the uptake of FM4-64 (a marker of endocytosis). Similar results were reproduced by disruption of the coronin-3-GDP-Rab27a interaction with the dominant-negative coronin 3, and coexpression of the GDP-Rab27a mutant rescued these changes. Taken together, our results indicate that interaction of GDP-Rab27a and coronin 3 is important in stimulus-endocytosis coupling, and that GTP- and GDP-Rab27a regulates insulin membrane recycling at the distinct stages. |
