B-lymphocyte antigen CD19 (B-lymphocyte surface antigen B4) (Differentiation antigen CD19) (T-cell surface antigen Leu-12) (CD antigen CD19)
1_MPPPR 6_ LLFFL 11_ LFLTP 16_ MEVRP 21_ EEPLV 26_ VKVEE 31_ GDNAV 36_ LQCLK 41_ GTSDG 46_ PTQQL 51_ TWSRE 56_ SPLKP 61_ FLKLS 66_ LGLPG 71_ LGIHM 76_ RPLAI 81_ WLFIF 86_ NVSQQ 91_ MGGFY 96_ LCQPG 101_ PPSEK 106_ AWQPG 111_ WTVNV 116_ EGSGE 121_ LFRWN 126_ VSDLG 131_ GLGCG 136_ LKNRS 141_ SEGPS 146_ SPSGK 151_ LMSPK 156_ LYVWA 161_ KDRPE 166_ IWEGE 171_ PPCLP 176_ PRDSL 181_ NQSLS 186_ QDLTM 191_ APGST 196_ LWLSC 201_ GVPPD 206_ SVSRG 211_ PLSWT 216_ HVHPK 221_ GPKSL 226_ LSLEL 231_ KDDRP 236_ ARDMW 241_ VMETG 246_ LLLPR 251_ ATAQD 256_ AGKYY 261_ CHRGN 266_ LTMSF 271_ HLEIT 276_ ARPVL 281_ WHWLL 286_ RTGGW 291_ KVSAV 296_ TLAYL 301_ IFCLC 306_ SLVGI 311_ LHLQR 316_ ALVLR 321_ RKRKR 326_ MTDPT 331_ RRFFK 336_ VTPPP 341_ GSGPQ 346_ NQYGN 351_ VLSLP 356_ TPTSG 361_ LGRAQ 366_ RWAAG 371_ LGGTA 376_ PSYGN 381_ PSSDV 386_ QADGA 391_ LGSRS 396_ PPGVG 401_ PEEEE 406_ GEGYE 411_ EPDSE 416_ EDSEF 421_ YENDS 426_ NLGQD 431_ QLSQD 436_ GSGYE 441_ NPEDE 446_ PLGPE 451_ DEDSF 456_ SNAES 461_ YENED 466_ EELTQ 471_ PVART 476_ MDFLS 481_ PHGSA 486_ WDPSR 491_ EATSL 496_ GSQSY 501_ EDMRG 506_ ILYAA 511_ PQLRS 516_ IRGQP 521_ GPNHE 526_ EDADS 531_ YENMD 536_ NPDGP 541_ DPAWG 546_ GGGRM 551_GTWST
1: Functions as a coreceptor for the B-cell antigen receptor complex (BCR) on B-lymphocytes (PubMed:29523808). Decreases the threshold for activation of downstream signaling pathways and for triggering B-cell responses to antigens (PubMed:1373518, PubMed:16672701, PubMed:2463100). Activates signaling pathways that lead to the activation of phosphatidylinositol 3-kinase and the mobilization of intracellular Ca(2+) stores (PubMed:12387743, PubMed:16672701, PubMed:9317126, PubMed:9382888). Is not required for early steps during B cell differentiation in the blood marrow (PubMed:9317126). Required for normal differentiation of B-1 cells (By similarity). Required for normal B cell differentiation and proliferation in response to antigen challenges (PubMed:1373518, PubMed:2463100). Required for normal levels of serum immunoglobulins, and for production of high-affinity antibodies in response to antigen challenge (PubMed:12387743, PubMed:16672701, PubMed:9317126)