Bcl10 Controls TCR- and FcR-Induced Actin Polymerization

Rueda D, Gaide O, Ho L, Lewkowicz E, Niedergang F, Hailfinger S, Rebeaud F, Guzzardi M, Conne B, Thelen M, Delon J, Ferch U, Mak TW, Ruland J, Schwaller J, Thome M
Source: J Immunol
Publication Date: (2007)
Issue: 178(7): 4373-84
Research Area:
Immunotherapy / Hematology
Cells used in publication:
Species: human
Tissue Origin: blood
Nucleofectorâ„¢ I/II/2b
Bcl10 plays an essential role in the adaptive immune response, because Bcl10-deficient lymphocytes show impaired Ag receptor-induced NF-kappaB activation and cytokine production. Bcl10 is a phosphoprotein, but the physiological relevance of this posttranslational modification remains poorly defined. In this study, we report that Bcl10 is rapidly phosphorylated upon activation of human T cells by PMA/ionomycin- or anti-CD3 treatment, and identify Ser(138) as a key residue necessary for Bcl10 phosphorylation. We also show that a phosphorylation-deficient Ser(138)/Ala mutant specifically inhibits TCR-induced actin polymerization yet does not affect NF-kappaB activation. Moreover, silencing of Bcl10, but not of caspase recruitment domain-containing MAGUK protein-1 (Carma1) induces a clear defect in TCR-induced F-actin formation, cell spreading, and conjugate formation. Remarkably, Bcl10 silencing also impairs FcgammaR-induced actin polymerization and phagocytosis in human monocytes. These results point to a key role of Bcl10 in F-actin-dependent immune responses of T cells and monocytes/macrophages.