αvβ5 integrin recruits the CrkII–Dock180–Rac1 complex for phagocytosis of apoptotic cells

ML Albert, JI Kim, RB Birge - Nature cell biology, 2000 - nature.com
ML Albert, JI Kim, RB Birge
Nature cell biology, 2000nature.com
Integrin receptors are important for the phagocytosis of apoptotic cells. However, little is
known about their function in mediating internalization, as previous studies used blocking
antibodies for the inhibition of binding. Here we show that the α v β 5 receptor mediates both
binding and internalization of apoptotic cells. Internalization is dependent upon signalling
through the β 5 cytoplasmic tail, and engagement of the α v β 5 heterodimer results in
recruitment of the p130 cas–CrkII–Dock180 molecular complex, which in turn triggers Rac1 …
Abstract
Integrin receptors are important for the phagocytosis of apoptotic cells. However, little is known about their function in mediating internalization, as previous studies used blocking antibodies for the inhibition of binding. Here we show that the α v β 5 receptor mediates both binding and internalization of apoptotic cells. Internalization is dependent upon signalling through the β 5 cytoplasmic tail, and engagement of the α v β 5 heterodimer results in recruitment of the p130 cas–CrkII–Dock180 molecular complex, which in turn triggers Rac1 activation and phagosome formation. In addition to defining integrin-receptor signalling as critical for the internalization of apoptotic material, our results also constitute the first evidence in human cells that the CED-2–CED-5–CED-10 complex defined in Caenorhabditis elegans is functionally analagous to the CrkII–Dock180–Rac1 molecular complex in mammalian cells. By linking the α v β 5 receptor to this molecular switch, we reveal an evolutionarily conserved signalling pathway that is responsible for the recognition and internalization of apoptotic cells by both professional and non-professional phagocytes.
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