- Chan, Vivien WF;
- Mecklenbräuker, Ingrid;
- Su, I-hsin;
- Texido, Gemma;
- Leitges, Michael;
- Carsetti, Rita;
- Lowell, Clifford A;
- Rajewsky, Klaus;
- Miyake, Kensuke;
- Tarakhovsky, Alexander
The B cell-specific transmembrane protein RP-105 belongs to the family of Drosophila toll-like proteins which are likely to trigger innate immune responses in mice and man. Here we demonstrate that the Src-family protein tyrosine kinase Lyn, protein kinase C beta I/II (PKCbetaI/II), and Erk2-specific mitogen-activated protein (MAP) kinase kinase (MEK) are essential and probably functionally connected elements of the RP-105-mediated signaling cascade in B cells. We also find that negative regulation of RP-105-mediated activation of MAP kinases by membrane immunoglobulin may account for the phenomenon of antigen receptor-mediated arrest of RP-105-mediated B cell proliferation.