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

MARÍA G MÁRQUEZ; FERNANDEZ TOME, MARIA DEL CARMEN; N.O. FAVALE,; LUCILA G. PESCIO; NORMA B. STERIN-SPEZIALE

AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY - (Print)

APS

Año: 2009 vol. 297 p. 1181 - 1191

0363-6127

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