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RhoC GTPase Activation Assay
09:58

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Published on: August 22, 2010

HLA class I signal transduction is dependent on Rho GTPase and ROK

Eric J Lepin1, Yi-Ping Jin, Sonali P Barwe

  • 1UCLA Immunogenetics Center, David Geffen School of Medicine, University of California, Los Angeles, 1000 Veteran Avenue, Los Angeles, CA 90095, USA.

Biochemical and Biophysical Research Communications
|September 8, 2004
PubMed

Chronic rejection is the major limitation to long-term allograft survival. HLA class I signaling pathways have been implicated in this process because ligation of class I molecules by anti-HLA antibodies (Ab) initiates intracellular signals in smooth muscle cells (SMC) and endothelial cells (EC) that synergize with growth factor receptors to elicit cell survival and proliferation. Anti-HLA Ab mediate cell proliferation and survival through a focal adhesion kinase dependent pathway that requires the integrity of the actin cytoskeleton. In this study, we investigated the role of Rho and Rho-kinase (ROK) in class I signal transduction. We show that class I ligation results in activation of Rho and increased stress fiber formation. In addition, inhibitors of Rho GTPase and ROK block HLA class I-mediated tyrosyl phosphorylation of paxillin and FAK, central elements of the focal adhesion signaling complex. These results suggest that HLA class I-induced signaling in EC is dependent on Rho GTPase and ROK.

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