RRC ID 48874
Author Tsuboi T, Fukuda M.
Title The Slp4-a linker domain controls exocytosis through interaction with Munc18-1.syntaxin-1a complex.
Journal Mol Biol Cell
Abstract Synaptotagmin-like protein 4-a (Slp4-a)/granuphilin-a is specifically localized on dense-core vesicles in certain neuroendocrine cells and negatively controls dense-core vesicle exocytosis through specific interaction with Rab27A. However, the precise molecular mechanism of its inhibitory effect on exocytosis has never been elucidated and is still a matter of controversy. Here we show by deletion and chimeric analyses that the linker domain of Slp4-a interacts with the Munc18-1.syntaxin-1a complex by directly binding to Munc18-1 and that this interaction promotes docking of dense-core vesicles to the plasma membrane in PC12 cells. Despite increasing the number of plasma membrane docked vesicles, expression of Slp4-a strongly inhibited high-KCl-induced dense-core vesicle exocytosis. The inhibitory effect by Slp4-a is absolutely dependent on the linker domain of Slp4-a, because substitution of the linker domain of Slp4-a by that of Slp5 (the closest isoform of Slp4-a that cannot bind the Munc18-1.syntaxin-1a complex) completely abrogated the inhibitory effect. Our findings reveal a novel docking machinery for dense-core vesicle exocytosis: Slp4-a simultaneously interacts with Rab27A and Munc18-1 on the dense-core vesicle and with syntaxin-1a in the plasma membrane.
Volume 17(5)
Pages 2101-12
Published 2006-5-1
DOI 10.1091/mbc.e05-11-1047
PII E05-11-1047
PMID 16481396
PMC PMC1446092
MeSH Animals Carrier Proteins / metabolism Cell Membrane / metabolism Exocytosis* Humans Membrane Fusion Membrane Proteins / metabolism Munc18 Proteins / metabolism* PC12 Cells Protein Interaction Mapping Protein Structure, Tertiary RNA, Small Interfering / genetics RNA, Small Interfering / pharmacology Rats Syntaxin 1 / metabolism* Transport Vesicles / metabolism* Vesicular Transport Proteins / antagonists & inhibitors Vesicular Transport Proteins / chemistry* Vesicular Transport Proteins / metabolism*
IF 3.791
Times Cited 53
DNA material pmRFP-C1-mouse Slp1 (RDB15089) pmRFP-C1-mouse Slp2-a (RDB15090) pmRFP-C1-mouse Slp3-a (RDB15091) pmRFP-C1-mouse Slp4-a (RDB15092) pmRFP-C1-mouse Slp5 (RDB15093).