The docking/fusion of transport vesicles mediated by the soluble NSF attachment protein receptors (SNAREs) is thought to be regulated by Sec1-related proteins. Munc-18-2, a member of this family, is predominantly expressed in the epithelial cells of several tissues. We demonstrate here that Munc-18-2 colocalizes with syntaxin 3 at the apical plasma membrane of intestinal epithelium and Caco-2 cells. The presence of a physical complex of the two proteins is verified by 2-way coimmunoprecipitation. The quantity of the complex is reduced by treatment of Caco-2 cells with the alkylating agent N-ethylmaleimide which also has an inhibitory effect on the ability of Munc-18-2 to associate with syntaxin 3 in vitro. The amount of Munc-18-2 in the complex increases upon treatment of the cells with the protein kinase C activator phorbol myristate acetate, indicating a functional connection between the complex and cell signalling. Increasing the amount of Munc-18-2 bound to syntaxin 3 by overexpression results in a marked decrease in the SNARE proteins SNAP-23 and cellubrevin bound to the syntaxin. These results define a novel functional complex of Munc-18-2 and syntaxin 3 involved in the regulation of apical membrane transport.
Interaction of Munc-18-2 with syntaxin 3 controls the association of apical SNAREs in epithelial cells
- Views Icon Views
- PDF LinkPDF
- Share Icon Share
- Search Site
K. Riento, T. Galli, S. Jansson, C. Ehnholm, E. Lehtonen, V.M. Olkkonen; Interaction of Munc-18-2 with syntaxin 3 controls the association of apical SNAREs in epithelial cells. J Cell Sci 1 September 1998; 111 (17): 2681–2688. doi: https://doi.org/10.1242/jcs.111.17.2681
Download citation file: