Rho-A is critical for osteoclast podosome organization, motility, and bone resorption

Meenakshi A. Chellaiah, Norihito Soga, Suzanne Swanson, Sandy McAllister, Ulises Alvarez, Dongmei Wang, Steven F. Dowdy, Keith A. Hruska

Research output: Contribution to journalArticlepeer-review

224 Scopus citations

Abstract

Rho plays a regulatory role in the formation of actin stress fibers and focal adhesions, and it is also involved in integrin-mediated signaling events. To study the role of Rho in α(v)β3/gelsolin-dependent signaling, the HIV-Tat peptide, hemagglutinin (HA)-tagged Rho(Val-14) (constitutively active) and Rho(Asn-19) (dominant negative) were transduced into avian osteoclasts. Protein transduction by HA-Tat was highly efficient, and 90-100% of the cells were transduced with HA-tagged proteins. We demonstrate here that Rho(Val-14) transduction (100 nM) stimulated gelsolin-associated phosphatidylinositol 3-kinase activity, podosome assembly, stress fiber formation, osteoclast motility, and bone resorption, mimicking osteoclast stimulation by osteopontin/α(v)β3. The effects of Rho(Val-14) transduction stimulation was time-dependent. C3 exoenzyme blocked the effects of Rho(Val- 14) and induced podosome disassembly, loss of motility, and inhibition of bone resorption. Transduction of Rho(Asn-19) produced podosome disassembly, and blocked osteopontin stimulation. These data demonstrate that integrin- dependent activation of phosphoinositide synthesis, actin stress fiber formation, podosome reorganization for osteoclast motility, and bone resorption require Rho stimulation.

Original languageEnglish
Pages (from-to)11993-12002
Number of pages10
JournalJournal of Biological Chemistry
Volume275
Issue number16
DOIs
StatePublished - Apr 21 2000

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