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Complexes of syndapin II with dynamin II promote vesicle formation at the trans-Golgi network

Item Type:Article
Title:Complexes of syndapin II with dynamin II promote vesicle formation at the trans-Golgi network
Creators Name:Kessels, M.M. and Dong, J. and Leibig, W. and Westermann, P. and Qualmann, B.
Abstract:The role of dynamin and so-called accessory proteins in endocytosis is well established. However, molecular details of the function(s) of dynamin II at the Golgi are largely unclear. We demonstrate that the ubiquitously expressed syndapin II isoform interacts with the proline-rich domain (PRD) of dynamin II through its Src-homology 3 (SH3) domain. Co-immunoprecipitation of endogenous syndapin II and dynamin II, and successful reconstitutions of such complexes at membranes in COS-7 cells, show the in vivo relevance of the interaction. Syndapin II can associate with Golgi membranes and this association increases upon Golgi exit block. Brefeldin A treatment clearly shows that the observed perinuclear localization of syndapin II co-localizing with syntaxin 6 reflects the Golgi complex and that it requires functional integrity of the Golgi. Syndapins are crucial for Golgi vesicle formation because antisyndapin antibodies, used either in in vitro reconstitutions or in living cells, inhibited this process. Both types of assays additionally revealed the essential role of syndapin II SH3 interactions with the dynamin II PRD in vesicle formation. An excess of the syndapin SH3 domain strongly inhibited budding from Golgi membranes in vitro. Likewise, overexpression of the syndapin SH3 domain or of a dynamin II variant incapable of associating with syndapin II (dynamin IIΔPRD) impaired trafficking of vesicular stomatitis virus glycoprotein (VSVG)-GFP in vivo. By contrast, full-length syndapin II-I had no negative effect, and instead promoted VSVG-GFP export from the Golgi. Importantly, a cytosolic fraction containing endogenous syndapin-dynamin complexes was sufficient to promote vesicle formation from Golgi membranes in a syndapin-dependent manner. Thus, syndapin-dynamin complexes are crucial and sufficient to promote vesicle formation from the trans-Golgi network.
Keywords:Biological Transport, COS Cells, Carrier Proteins, Cell Line, Cercopithecus aethiops, Dynamin II, Golgi Apparatus, Intracellular Membranes, Protein Binding, Protein Isoforms, Synaptic Vesicles, src Homology Domains, Animals
Source:Journal of Cell Science
Publisher:Company of Biologists
Page Range:1504-1516
Date:15 April 2006
Official Publication:https://doi.org/10.1242/jcs.02877
PubMed:View item in PubMed

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