Rab35 regulates phagosome formation through recruitment of ACAP2 in macrophages during FcγR-mediated phagocytosis.

Abstract

Phagosome formation and subsequent maturation are complex sequences of events that involve actin cytoskeleton remodeling and membrane trafficking. Here, we demonstrate that the Ras-related protein Rab35 is involved in the early stage of FcγR-mediated phagocytosis in macrophages. Live-cell image analysis revealed that Rab35 was markedly concentrated at the membrane where IgG-opsonized erythrocytes (IgG-Es) are bound. Rab35 silencing by RNA interference (RNAi) or the expression of GDP- or GTP-locked Rab35 mutant drastically reduced the rate of phagocytosis of IgG-Es. Actin-mediated pseudopod extension to form phagocytic cups was disturbed by the Rab35 silencing or the expression of GDP-Rab35, although initial actin assembly at the IgG-E binding sites was not inhibited. Furthermore, GTP-Rab35-dependent recruitment of ACAP2, an ARF6 GTPase-activating protein, was shown in the phagocytic cup formation. Concomitantly, overexpression of ACAP2 along with GTP-locked Rab35 showed a synergistic inhibitory effect on phagocytosis. It is likely that Rab35 regulates actin-dependent phagosome formation by recruiting ACAP2, which might control actin remodeling and membrane traffic through ARF6.

DOI: 10.1242/jcs.083881

Cite this paper

@article{Egami2011Rab35RP, title={Rab35 regulates phagosome formation through recruitment of ACAP2 in macrophages during FcγR-mediated phagocytosis.}, author={Youhei Egami and Mitsunori Fukuda and Nobukazu Araki}, journal={Journal of cell science}, year={2011}, volume={124 Pt 21}, pages={3557-67} }