Cdc42-driven podosome formation in endothelial cells.
Ectopic expression of a constitutive active mutant of the GTPase Cdc42 (V12Cdc42) in vascular endothelial cells triggers the dissolution of stress fibres and focal adhesion contacts and causes the repolymerisation of actin into dots. Each punctate structure consists of an F-actin core surrounded by a vinculin ring, consistent with the definition of podosomes. We now report further analysis of these complexes and show the presence of established podosomal markers such as cortactin, gelsolin, dynamin, N-WASP, and Arp2/3 which are absent in focal adhesions. Endothelial podosomes appear as randomly distributed conical structures, distributed on, but restricted to, the ventral membrane and confined to contact sites between cells and their substratum. The nature of the extracellular matrix does not influence podosome formation nor their spatial organisation. Induction of podosomes in response to V12Cdc42 is not associated with a migratory nor with a proliferative phenotype. These results add endothelial cells to the list of cell types endowed with the ability to form podosomes in vitro and raise the possibility that endothelial cells could form such structures under certain physiological or pathological conditions.
Institut Européen de Chimie-Biologie, Université Bordeaux 1, Pessac, and INSERM Unité 441, Université Bordeaux Victor Segalen Bordeaux 2, Bordeaux, France.
Violaine
V
Moreau
Florence
F
Tatin
Christine
C
Varon
Guerric
G
Anies
Catherine
C
Savona-Baron
Elisabeth
E
Génot
D000818:Animals; D015815:Cell Adhesion Molecules / Q000502:physiology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism / Q000648:ultrastructure*; D004730:Endothelium, Vascular / Q000166:cytology / Q000648:ultrastructure*; D005109:Extracellular Matrix / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D009154:Mutation; D013552:Swine; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
D015815:Cell Adhesion Molecules; D020764:cdc42 GTP-Binding Protein