B cell adaptor for phosphoinositide 3-kinase (BCAP) is a tyrosine kinase substrate that bridges B cell receptor (BCR) associated kinases to the PIK3 pathway. Syk, Btk or Lyn-dependent tyrosine phosphorylation of BCAP, provides binding sites for the p85 subunit of PIK3. BCAP mRNA is present in mouse spleen, thymus, liver, lung, macrophage and B cell lines. Human BCAP maps to chromosome 10q24.2.
Function:
Involved in the activation of phosphoinositide 3-kinase (PI3K) in B-cells and in natural killer (NK) cells. Couples B-cell antigen receptor (BCR) to PI3K activation by providing a docking site for the PI3K subunit PIK3R1, which contributes to B-cell development. Seems to have a complementary role with CD19 in PI3K activation (By similarity). May be involved in the survival of mature B cells via activation of REL.
Subunit:
Homooligomer (By similarity). Interacts (phosphorylated on tyrosine residues within YXXM motifs) with PIK3R1 (via SH2 domain); required for BCR- and TLR-mediated activation of phosphoinositide 3-kinase. Interacts (via polyproline SLCterminal region) with ABI1 (via SH3 domain); the interaction promotes phosphorylation of PIK3AP1 by ABL1. May interact with MYD88 and TIRAP (By similarity).
Subcellular Location:
Cytoplasm. Cell membrane.
Tissue Specificity:
Expressed in natural killer (NK) cells.
Post-translational modifications:
Phosphorylated on tyrosine residues within the YXXM motifs by BTK and SYK (By similarity). Isoform 1 and isoform 2 are phosphorylated on tyrosine residues, most likely within the YXXM motifs, via CD19 activation (By similarity).
Phosphorylated on tyrosine residues in SLCterminus region by ABL1 and SLVabl.
Similarity:
Contains 1 DBB domain.
SWISS:
Q6ZUJ8
Gene ID:
118788
Database links:
Entrez Gene: 118788 Human
Entrez Gene: 83490 Mouse
Omim: 607942 Human
SwissProt: Q6ZUJ8 Human
SwissProt: Q9EQ32 Mouse
Unigene: 310456 Human
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