CD19

SECTIONS

1 - Function
2 - Post-translational modifications
3 - Tissue specificity
4 - Cellular localization
5 - Alternative names
6 - Database links
7 - Target type
8 - Primary research area
9 - Other research areas
10 - Molecular weight

Function

Functions as a coreceptor for the B-cell antigen receptor complex (BCR) on B-lymphocytes. Decreases the threshold for activation of downstream signaling pathways and for triggering B-cell responses to antigens (By similarity). Activates signaling pathways that lead to the activation of phosphatidylinositol 3-kinase and the mobilization of intracellular Ca(2+) stores (PubMed:12387743, PubMed:20101619, PubMed:9382888). Is not required for early steps during B cell differentiation in the blood marrow (PubMed:7542548, PubMed:7543183, PubMed:9317126). Required for normal differentiation of B-1 cells (PubMed:12387743, PubMed:7542548, PubMed:7543183). Required for normal B cell differentiation and proliferation in response to antigen challenges (PubMed:12387743, PubMed:7542548, PubMed:9317126). Required for normal levels of serum immunoglobulins, and for production of high-affinity antibodies in response to antigen challenge (PubMed:12387743, PubMed:7542548, PubMed:7543183).

Post-translational modifications

Phosphorylated on tyrosine following B-cell activation (PubMed:20101619). Phosphorylated on tyrosine residues by LYN (By similarity). Tyrosine residues are phosphorylated sequentially after activation of the B cell receptor. Phosphorylation of Tyr-522 is extremely rapid, followed by phosphorylation at Tyr-402. In contrast, phosphorylation of Tyr-493 appears more slowly and is more transient, returning rapidly to basal levels (PubMed:20101619).

Tissue specificity

Detected on B cells in spleen, bone marrow, thymus and lymph nodes (PubMed:12387743, PubMed:20101619, PubMed:7542548). Detected on peripheral blood lymphocytes (at protein level) (PubMed:7543183).