CD19

CD19 (CD19 Molecule) is a Protein Coding gene. Diseases associated with CD19 include Immunodeficiency, Common Variable, 3 and Common Variable Immunodeficiency. Among its related pathways are RET signaling and Hematopoietic Stem Cell Differentiation Pathways and Lineage-specific Markers. Gene Ontology (GO) annotations related to this gene include signal transducer activity, downstream of receptor.

CD19 Molecule

CD19 Molecule; B-Lymphocyte Surface Antigen B4; T-Cell Surface Antigen Leu-12; Differentiation Antigen CD19; CD19 Antigen; B-Lymphocyte Antigen CD19; CVID3; B4;

Functions as 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 (PubMed:2463100, PubMed:1373518, PubMed:16672701).
Activates signaling pathways that lead to the activation of phosphatidylinositol 3-kinase and the mobilization of intracellular Ca2+ stores (PubMed:9382888, PubMed:9317126, PubMed:12387743, PubMed:16672701).
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:2463100, PubMed:1373518).
Required for normal levels of serum immunoglobulins, and for production of high-affinity antibodies in response to antigen challenge (PubMed:9317126, PubMed:12387743, PubMed:16672701).

Antigen receptor-mediated signaling pathway Source: UniProtKB
B-1 B cell differentiation Source: Ensembl
B cell proliferation involved in immune response Source: UniProtKB
B cell receptor signaling pathway Source: UniProtKB
Immunoglobulin mediated immune response Source: UniProtKB
Positive regulation of phosphatidylinositol 3-kinase activity Source: UniProtKB
Positive regulation of protein kinase B signaling Source: Reactome
Positive regulation of release of sequestered calcium ion into cytosol Source: UniProtKB
Regulation of B cell activation Source: UniProtKB
Regulation of B cell receptor signaling pathway Source: UniProtKB
Regulation of complement activation Source: Reactome
Regulation of immune response Source: Reactome

Cell membrane; Membrane raft

Immunodeficiency, common variable, 3 (CVID3): A primary immunodeficiency characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen. The defect results from a failure of B-cell differentiation and impaired secretion of immunoglobulins; the numbers of circulating B-cells is usually in the normal range, but can be low.

Extracellular: 20-291
Helical: 292-313
Cytoplasmic: 314-556

Phosphorylated on tyrosine following B-cell activation (PubMed:7684160, PubMed:7687539, PubMed:10706702, PubMed:12387743). Phosphorylated on tyrosine residues by LYN (PubMed:7687428). Tyrosine residues are phosphorylated sequentially after activation of the B cell receptor. Phosphorylation of Tyr-531 is extremely rapid, followed by phosphorylation at Tyr-409. In contrast, phosphorylation of Tyr-500 appears more slowly and is more transient, returning rapidly to basal levels (By similarity).