Bradykinin induces the formation of vesicle-like structures containing vinculin and PtdIns(4,5)P2 in renal papillary collecting duct cells

MARÍA GABRIELA MARQUEZ; MARIA C. FERNÁNDEZ TOME; NICOLAS O. FAVALE; LUCILA G PESCIO; NORMA B. STERIN SPEZIALE

AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY - (Print)

APS

Año: 2009 vol. 294 p. 603 - 613

0363-6127

Focal adhesions (FAs) are structures of cell attachment to the extracellular matrix. We have previously demonstrated that the intrarenal hormone bradykinin (BK) induces FAs restructuring in papillary collecting duct cells by dissipation of vinculin, but not talin, from FAs, through a mechanism that involves PLC activation, and that it also induces actin cytoskeleton reorganization. In the present study we investigated the mechanism by which BK induces the dissipation of vinculin-stained FAs in collecting duct cells. We found that BK induces the internalization of vinculin by a noncaveolar, and independent pinocytic pathway, and that at least a fraction of this protein is delivered to the recycling endosomal compartment, where it colocalizes with the transferrin receptor. As regards the reassembly of vinculin-stained FAs, we found that BK induces the formation of PtdIns(4,5)P2-enriched vinculin-containing vesicles, which, by following a polarized exocytic route, transport vinculin to the site of FA assembly, an action that depends on actin filaments. The present study, which was carried out under physiological conditions with cells that were not genetically manipulated, show for the first time that BK induces the formation of vesicle-like structures containing vinculin and PtdIns(4,5)P2, which transport vinculin to the site of FA assembly. Therefore, the modulation of the formation of these vesicle-like structures could be a physiological mechanism through which the cell can reuse the BK-induced internalized vinculin to be delivered for newly forming FAs in renal papillary collecting duct cells.