Endothelial cell migration on fibronectin is regulated by syntaxin 6-mediated alpha5beta1 integrin recycling.

ABSTRACT: The ?5?1 integrin heterodimer regulates many processes that contribute to embryonic development and angiogenesis, in both physiological and pathological contexts. As one of the major adhesion complexes on endothelial cells, it plays a vital role in adhesion and migration along the extracellular matrix. We recently showed that angiogenesis is modulated by syntaxin 6, a Golgi- and endosome-localized t-SNARE, and that it does so by regulating the post-Golgi trafficking of VEGFR2. Here we show that syntaxin 6 is also required for ?5?1 integrin-mediated adhesion of endothelial cells to, and migration along, fibronectin. We demonstrate that syntaxin 6 and ?5?1 integrin colocalize in EEA1-containing early endosomes, and that functional inhibition of syntaxin 6 leads to misrouting of ?1 integrin to the degradation pathway (late endosomes and lysosomes) rather transport along recycling pathway from early endosomes; an increase in the pool of ubiquitinylated ?5 integrin and its lysosome-dependent degradation; reduced cell spreading on fibronectin; decreased Rac1 activation; and altered Rac1 localization. Collectively, our data show that functional syntaxin 6 is required for the regulation of ?5?1-mediated endothelial cell movement on fibronectin. These syntaxin 6-regulated membrane trafficking events control outside-in signaling via haptotactic and chemotactic mechanisms.

SUBMITTER: Tiwari A 

PROVIDER: S-EPMC3196105 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature