Rho GTPases in osteoclasts: Orchestrators of podosome arrangement

Stéphane Ory (1) , Hélène Brazier (2) , Géraldine Pawlak (3, 2) , Anne Blangy (2)

1 INCI - Institut des Neurosciences Cellulaires et Intégratives
2 CRBM - Centre de recherche en Biologie Cellulaire
3 INSERM U823 - Institut d'oncologie/développement Albert Bonniot de Grenoble

Cells from the myeloid lineage, namely macrophages, dendritic cells and osteoclasts, develop podosomes instead of stress fibers and focal adhesions to adhere and migrate. Podosomes share many components with focal adhesions but differ in their molecular organization, with a dense core of polymerized actin surrounded by scaffolding proteins, kinases and integrins. Podosomes are found either isolated both in macrophages and dendritic cells or arranged into superstructures in osteoclasts. When osteoclasts resorb bone, they form an F-actin rich sealing zone, which is a dense array of connected podosomes that firmly anchors osteoclasts to bone. It delineates a compartment in which protons and proteases are secreted to dissolve and degrade the mineralized matrix. Since Rho GTPases have been shown to control F-actin stress fibers and focal adhesions in mesenchymal cells, the question of whether they could also control podosome formation and arrangement in cells from the myeloid lineage, and particularly in osteoclasts, rapidly emerged. This article considers recent advances made in our understanding of podosome arrangements in osteoclasts and how Rho GTPases may control it.

Mots clés: Wrch-1; RhoU; Rho GTPases; Sealing zone; Osteoclast; Podosome; WASP

Domaines: Biologie cellulaire; Biochimie, Biologie Moléculaire

Stéphane Ory, Hélène Brazier, Géraldine Pawlak, Anne Blangy. Rho GTPases in osteoclasts: Orchestrators of podosome arrangement. European Journal of Cell Biology, 2008, 87 (8-9), pp.469-477. ⟨10.1016/j.ejcb.2008.03.002⟩. ⟨hal-02323478v2⟩