Bradykinin induces vinculin– stained focal adhesions (FA) dissipation by vesicles internalization

MARQUEZ MG; FERNANDEZ TOME MC; FAVALE NO; STERIN SPEZIALE NB

Mar del Plata-Argentina

Congreso; XLIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2007

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

FA are structures of cell attachment to the extracellular matrix. Previously, we showed that bradykinin (BK) induces dissipation of vinculin-, but not talin-, staining FA by a mechanism that involves activation of PLC, suggesting that BK could be inducing a restructuring of FA. Now, we investigated the mechanism of vinculin - containing FA dissipation. We treated cultured rat renal papillary collecting duct cells with BK (1, 5 and 10 minutes) and analyzed the cells by confocal microscopy to study the route of vinculin internalization. After BK stimulation, the number of FA per cell decrease concomitant with the appearance of vesicles containing vinculin and PIP2, in the citosol. To ascertain whether these vesicles are formed via caveolin – coated intermediates, we analyzed the distribution of caveolin and vinculin by double immunofluorescence. Caveolin is detected in punctuate arrays but is not present in vinculin-containing vesicles in BK treated cells. To test another endocytic rout, we pre-incubated cultured cells with the fluid-phase endocytosis marker fluorescent dextran (F-Dex) (5 min) before BK stimulation. Vinculin-containing vesicles do not internalized F-Dex after BK treatment. Taken together, BK induces vinculin – stained FA dissipation by the internalization of vesicles containing vinculin and PIP2, by a caveolae -, and fluid phase- independent endocytic pathway.