Molecular mechanism of secretory vesicle docking.
Docking, the stable association of secretory vesicles with the plasma membrane, is considered to be the necessary first step before vesicles gain fusion-competence, but it is unclear how vesicles dock. In adrenal medullary chromaffin cells, access of secretory vesicles to docking sites is controlled by dense F-actin (filamentous actin) beneath the plasma membrane. Recently, we found that, in the absence of Munc18-1, the number of docked vesicles and the thickness of cortical F-actin are affected. In the present paper, I discuss the possible mechanism by which Munc18-1 modulates cortical F-actin and how it orchestrates the docking machinery via an interaction with syntaxin-1. Finally, a comparison of Munc18's role in embryonic mouse and adult bovine chromaffin cell model systems will be made to clarify observed differences in cortical F-actin as well as docking phenotypes.
de Wit
Heidi
H
Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands. heidi.de.wit@cncr.vu.nl
D000199:Actins / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D019439:Chromaffin Cells / Q000166:cytology / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D051938:Munc18 Proteins / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D013569:Synapses / Q000378:metabolism; D050827:Syntaxin 1 / Q000378:metabolism
D000199:Actins; D051938:Munc18 Proteins; D050827:Syntaxin 1