References
Query Results -- Details
MGI Accession ID: MGI:3773085
J Number: J:131150
Other Accession IDs:
Title: Activation of the small GTPase Rac2 via the B cell receptor regulates B cell adhesion and immunological-synapse formation.
Authors: Arana E; Vehlow A; Harwood NE; Vigorito E; Henderson R; Turner M; Tybulewicz VL; Batista FD
Journal: Immunity
Volume: 28
Issue: 1
Date: 2008 Jan
Year: 2008
Pages: 88-99
Review Status: Peer Reviewed
Abstract:
The integrin leukocyte function-associated antigen-1 (LFA-1) is important in the promotion of B cell adhesion, thereby facilitating immunological synapse (IS) formation and B cell activation. Despite this significance, the associated signaling mechanisms regulating LFA-1 activation remain elusive. Here, we show that both isoforms of the small GTPase Rac expressed by primary B cells, Rac1 and Rac2, were activated rapidly downstream of Src-family kinases, guanine-nucleotide exchange factors Vav1 and Vav2, and phosphoinositide-3 kinase (PI3K) after BCR engagement. We identify Rac2, but not Rac1, as critical for B cell adhesion to intercellular adhesion molecule-1 (ICAM-1) and IS formation. Furthermore, B cells expressing constitutively active Rac2 are highly adhesive. We observe that Rac2-deficient B cells exhibit lower amounts of Rap1-GTP and severe actin polymerization defects, identifying a potential mechanism underlying their behavior. We postulate that this critical role for Rac2 in mediating B cell adhesion and IS formation might apply in all lymphocytes.
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