a cell surface molecule which assembles with the antigen receptor of B lymphocytes. A critical signal transduction molecule that regulates B lymphocyte development, activation, and differentiation. Ligation increases intracellular calcium levels and decreases the threshold for antigen receptor signaling. Germinal center formation is significantly reduced in CD19-deficient mice. Note: This description may include information from UniProtKB.
Protein type: Cell surface; Membrane protein, integral