Requirements for Vav guanine nucleotide exchange factors and Rho GTPases in FcγR- and complement-mediated phagocytosis

Amy B. Hall, M. Angelica Martinez Gakidis, Michael Glogauer, Julie L. Wilsbacher, Sizhen Gao, Wojciech Swat, Joan S. Brugge

Research output: Contribution to journalArticle

127 Scopus citations

Abstract

Vav guanine nucleotide exchange factors (GEFs) have been implicated in cell adhesion by integrin and immune response receptors through the regulation of Rho GTPases. Here, we examine the role of Vav and Rho GTPases in phagocytosis by using primary murine macrophages. The genetic deletion of Rac1 and Rac2 prevents phagocytosis mediated by integrin and Fcγ receptors (FcγR), whereas the genetic deletion of Vav1 and Vav3 only prevents integrin-mediated phagocytosis through the complement receptor αMβ 2. In addition, a Rac1/2 or Vav1/3 deficiency blocks Arp2/3 recruitment and actin polymerization at the complement-induced phagosome, indicating that these proteins regulate early steps in phagocytosis. Moreover, constitutively active Rac is able to rescue actin polymerization and complement-mediated phagocytosis in Vav-deficient macrophages. These studies indicate that Rac is critical for complement- and FcγR-mediated phagocytosis. In contrast, Vav is specifically required for complement-mediated phagocytosis, suggesting that Rac is regulated by GEFs other than Vav downstream of the FcγR.

Original languageEnglish
Pages (from-to)305-316
Number of pages12
JournalImmunity
Volume24
Issue number3
DOIs
StatePublished - Mar 1 2006

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