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Citation

Lim J, Hotchin NA & Caron E (2011) Ser(756) of β2 integrin controls Rap1 activity during inside-out activation of αMβ2. Biochemical Journal, 437 (3), pp. 461-467. https://doi.org/10.1042/BJ20101666

Abstract
During αMβ2-mediated phagocytosis, the small GTPase Rap1 activates the β2 integrin by binding to a region between residues 732 and 761. Using COS-7 cells transfected with αMβ2, we show that αMβ2 activation by the phorbol ester PMA involves Ser756 of β2. This residue is critical for the local positioning of talin and biochemically interacts with Rap1. Using the CaM (calmodulin) antagonist W7, we found Rap1 recruitment and the inside-out activation of αMβ2 to be affected. We also report a role for CaMKII (calcium/CaM-dependent kinase II) in the activation of Rap1 during integrin activation. These results demonstrate a distinct physiological role for Ser756 of β2 integrin, in conjunction with the actions of talin and Rap1, during αMβ2 activation in macrophages.

Keywords
αMβ2; calcium/calmodulin-dependent kinase II (CaMKII); integrin; phagocytosis; Rap1; talin

Journal
Biochemical Journal: Volume 437, Issue 3