Lck Non-receptor tyrosine-protein kinase that plays an essential role in the selection and maturation of developing T-cells in the thymus and in the function of mature T-cells. Plays a key role in T-cell antigen receptor (TCR)-linked signal transduction pathways. Constitutively associated with the cytoplasmic portions of the CD4 and CD8 surface receptors. Association of the TCR with a peptide antigen-bound MHC complex facilitates the interaction of CD4 and CD8 with MHC class II and class I molecules, respectively, thereby recruiting the associated LCK protein to the vicinity of the TCR/CD3 complex. LCK then phosphorylates tyrosine residues within the immunoreceptor tyrosine-based activation motifs (ITAM) of the cytoplasmic tails of the TCR-gamma chains and CD3 subunits, initiating the TCR/CD3 signaling pathway. Once stimulated, the TCR recruits the tyrosine kinase ZAP70, that becomes phosphorylated and activated by LCK. Following this, a large number of signaling molecules are recruited, ultimately leading to lymphokine production. LCK also contributes to signaling by other receptor molecules. Associates directly with the cytoplasmic tail of CD2, which leads to hyperphosphorylation and activation of LCK. Also plays a role in the IL2 receptor-linked signaling pathway that controls the T-cell proliferative response. Binding of IL2 to its receptor results in increased activity of LCK. Is expressed at all stages of thymocyte development and is required for the regulation of maturation events that are governed by both pre-TCR and mature alpha beta TCR. Phosphorylates other substrates including RUNX3, PTK2B/PYK2, the microtubule-associated protein MAPT, RHOH or TYROBP. Interacts with FYB2. Belongs to the protein kinase superfamily. Tyr protein kinase family. SRC subfamily. Expressed specifically in lymphoid cells. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: EC; Kinase, protein; Oncoprotein; Protein kinase, TK; Protein kinase, tyrosine (non-receptor); Src family; TK group
Chromosomal Location of Human Ortholog: 4 D2.2|4 63.26 cM
Cellular Component:  cell-cell junction; cytoplasm; endocytic vesicle; extrinsic component of cytoplasmic side of plasma membrane; glutamatergic synapse; immunological synapse; membrane; membrane raft; pericentriolar material; plasma membrane; postsynaptic specialization, intracellular component
Molecular Function:  antigen binding; ATP binding; ATPase binding; CD4 receptor binding; CD8 receptor binding; identical protein binding; kinase activity; non-membrane spanning protein tyrosine kinase activity; nucleotide binding; phosphatidylinositol 3-kinase binding; phosphotyrosine residue binding; protein antigen binding; protein binding; protein C-terminus binding; protein kinase activity; protein kinase binding; protein phosphatase binding; protein serine/threonine phosphatase activity; protein tyrosine kinase activity; protein-containing complex binding; SH2 domain binding; signaling receptor binding; T cell receptor binding; transferase activity
Biological Process:  activation of cysteine-type endopeptidase activity involved in apoptotic process; B cell receptor signaling pathway; cell differentiation; cell surface receptor signaling pathway; peptidyl-tyrosine autophosphorylation; peptidyl-tyrosine phosphorylation; phosphorylation; positive regulation of gamma-delta T cell differentiation; positive regulation of gene expression; positive regulation of heterotypic cell-cell adhesion; positive regulation of intrinsic apoptotic signaling pathway; positive regulation of leukocyte cell-cell adhesion; positive regulation of T cell activation; positive regulation of tyrosine phosphorylation of STAT protein; positive regulation of uterine smooth muscle contraction; protein autophosphorylation; protein phosphorylation; regulation of regulatory T cell differentiation; regulation of T cell receptor signaling pathway; release of sequestered calcium ion into cytosol; response to drug; response to hydrogen peroxide; response to mechanical stimulus; response to metal ion; T cell differentiation; transmembrane receptor protein tyrosine kinase signaling pathway
Reference #:  P06240 (UniProtKB)
Alt. Names/Synonyms: Hck-3; Lck; Leukocyte C-terminal Src kinase; LSK; Lsk-t; Lskt; Lymphocyte cell-specific protein-tyrosine kinase; lymphocyte protein tyrosine kinase; OTTMUSP00000010178; OTTMUSP00000010179; p56-LCK; p56<lc; p56<lck>; p56Lck; Proto-oncogene tyrosine-protein kinase LCK; RP23-209C6.8
Gene Symbols: Lck
Molecular weight: 57,943 Da
Basal Isoelectric point: 5.13  Predict pI for various phosphorylation states
CST Pathways:  GPCR Signaling to MAPKs  |  T Cell Receptor Signaling  |  Tyrosine Kinases & Substrates
Protein-Specific Antibodies, siRNAs or Recombinant Proteins from Cell Signaling Technology® Total Proteins
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Cross-references to other databases:  STRING  |  Reactome  |  BioGPS  |  KinBase  |  Pfam  |  ENZYME  |  Phospho.ELM  |  NetworKIN  |  GeneCards  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene  |  Ensembl Protein