The interaction with caveolae-associated proteins regulates enolase-1 subcellular localization

Cell surface-associated proteolysis plays a crucial role in embryonic development, monocyte/macrophage recruitment and tumor cell invasion. The glycolytic enzyme enolase-1 (ENO-1) is translocated from the cytoplasm to the cell surface, where it binds plasminogen (PLG) to enhance pericellular plasmin production and cell motility. In our study, ENO-1 was found to localize to a specialized subset of lipid rafts called caveolae as demonstrated by fluorescence confocal microscopy and sucrose gradient ultracentrifugation. Co-immunoprecipitation studies revealed that ENO-1 interacts with caveolin (Cav)-1, but not with Cav-2, via caveolin scaffolding domain (CSD). Moreover, an evolutionary conserved caveolin-binding motif (CBM) 296FDQDDWGAW304 was identified within ENO-1. Point mutation W301A within ENO-1 CBM was, however, not sufficient to disrupt ENO-1-Cav-1 interaction, whereas mutations F296A and W304A markedly affected ENO-1 protein expression. Furthermore, ENO-1 was found associated with annexin 2 (Annx2), representing another caveolar protein, and this interaction was dependent on Cav-1 expression. Knockdown of Cav-1 and Annx2 markedly decreased cell surface expression of ENO-1. ENO-1 overexpression increased cell migration and invasion in a Cav-1-dependent manner. Thus, the differential association of ENO-1 with caveolar proteins regulates ENO-1 subcellular localization and consequently, ENO-1-dependent cell migration and invasion.

Source: BJ Cell - March 14, 2014 Category: Biochemistry Authors: D Zakrzewicz, M Didiasova, A Zakrzewicz, A C. Hocke, F Uhle, P Markart, K T. Preissner, M Wygrecka Tags: BJ Cell Source Type: research