Enables several functions, including CD4 receptor binding activity; protein antigen binding activity; and protein phosphatase binding activity. Involved in release of sequestered calcium ion into cytosol. Acts upstream of or within several processes, including positive regulation of macromolecule metabolic process; protein phosphorylation; and regulation of T cell differentiation. Located in cell-cell junction. Colocalizes with plasma membrane. Is expressed in several structures, including 2-cell stage embryo; nervous system; neural ectoderm; sensory organ; and thymus primordium. Human ortholog(s) of this gene implicated in immunodeficiency 22. Orthologous to human LCK (LCK proto-oncogene, Src family tyrosine kinase).
MGI Description
PHENOTYPE: Mice homozygous for mutations of this gene exhibit thymic atrophy with reduced numbers of peripheral T cells. Null mutants have few double positive and no mature single positive (SP) thymocytes. A hypomorph has decreased expression of CD3epsilon chain on SP thymocytes, whose numbers are reduced. [provided by MGI curators]