B-cell antigen receptor complex-associated protein alpha chain (Ig-alpha) (MB-1 membrane glycoprotein) (Membrane-bound immunoglobulin-associated protein) (Surface IgM-associated protein) (CD antigen CD79a)
1_MPGGP 6_ GVLQA 11_ LPATI 16_ FLLFL 21_ LSAVY 26_ LGPGC 31_ QALWM 36_ HKVPA 41_ SLMVS 46_ LGEDA 51_ HFQCP 56_ HNSSN 61_ NANVT 66_ WWRVL 71_ HGNYT 76_ WPPEF 81_ LGPGE 86_ DPNGT 91_ LIIQN 96_ VNKSH 101_ GGIYV 106_ CRVQE 111_ GNESY 116_ QQSCG 121_ TYLRV 126_ RQPPP 131_ RPFLD 136_ MGEGT 141_ KNRII 146_ TAEGI 151_ ILLFC 156_ AVVPG 161_ TLLLF 166_ RKRWQ 171_ NEKLG 176_ LDAGD 181_ EYEDE 186_ NLYEG 191_ LNLDD 196_ CSMYE 201_ DISRG 206_ LQGTY 211_ QDVGS 216_ LNIGD 221_VQLEK
1: Required in cooperation with CD79B for initiation of the signal transduction cascade activated by binding of antigen to the B-cell antigen receptor complex (BCR) which leads to internalization of the complex, trafficking to late endosomes and antigen presentation. Also required for BCR surface expression and for efficient differentiation of pro- and pre-B-cells. Stimulates SYK autophosphorylation and activation. Binds to BLNK, bringing BLNK into proximity with SYK and allowing SYK to phosphorylate BLNK. Also interacts with and increases activity of some Src-family tyrosine kinases. Represses BCR signaling during development of immature B-cells