This gene encodes a cytoplasmic linker or adaptor protein
that plays a critical role in B cell development. This protein
bridges B cell receptor-associated kinase activation with
downstream signaling pathways, thereby affecting various biological
functions. The phosphorylation of five tyrosine residues is
necessary for this protein to nucleate distinct signaling effectors
following B cell receptor activation. Mutations in this gene cause
hypoglobulinemia and absent B cells, a disease in which the pro- to
pre-B-cell transition is developmentally blocked. Deficiency in
this protein has also been shown in some cases of pre-B acute
lymphoblastic leukemia. Alternatively spliced transcript variants
encoding different isoforms have been found for this gene.
