Tyrosin-protein kinase Lck

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LCK
Available structures PDB Ortholog search: E9PI33 PDBe E9PI33 RCSB List of PDB id codes 1BHF, 1BHH, 1CWD, 1CWE, 1FBZ, 1H92, 1IJR, 1KIK, 1LCJ, 1LCK, 1LKK, 1LKL, 1Q68, 1Q69, 1QPC, 1QPD, 1QPE, 1QPJ, 1X27, 2IIM, 2OF2, 2OF4, 2OFU, 2OFV, 2OG8, 2PL0, 2ZM1, 2ZM4, 2ZYB, 3AC1, 3AC2, 3AC3, 3AC4, 3AC5, 3AC8, 3ACJ, 3ACK, 3AD4, 3AD5, 3AD6, 3B2W, 3BRH, 3BYM, 3BYO, 3BYS, 3BYU, 3KMM, 3KXZ, 3LCK, 3MPM, 4D8K, 4C3F
Identifiers
Aliases	LCK, LCK proto-oncogene, Src family tyrosine kinase, IMD22, LSK, YT16, p56lck, pp58lck
External IDs	OMIM: 153390; MGI: 96756; HomoloGene: 3911; GeneCards: LCK; OMA:LCK - orthologs
Gene location (Human) Chr. Chromosome 1 (human)[1] Band 1p35.2 Start 32,251,239 bp[1] End 32,286,165 bp[1]
Gene location (Mouse) Chr. Chromosome 4 (mouse)[2] Band 4 D2.2|4 63.26 cM Start 129,442,137 bp[2] End 129,467,434 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in thymus granulocyte lymph node blood appendix spleen epithelium of nasopharynx mucosa of ileum superficial temporal artery tonsil Top expressed in thymus mesenteric lymph nodes spleen blood otic placode submandibular gland otic vesicle subcutaneous adipose tissue ankle joint epiblast More reference expression data BioGPS More reference expression data
Gene ontology Molecular function transferase activity nucleotide binding protein kinase activity CD4 receptor binding ATPase binding SH2 domain binding CD8 receptor binding phosphatidylinositol 3-kinase binding protein C-terminus binding protein binding identical protein binding protein phosphatase binding ATP binding protein kinase binding phosphatidylinositol-4,5-bisphosphate 3-kinase activity kinase activity protein serine/threonine phosphatase activity non-membrane spanning protein tyrosine kinase activity phosphotyrosine residue binding protein tyrosine kinase activity T cell receptor binding signaling receptor binding Cellular component cytoplasm cytosol membrane extrinsic component of cytoplasmic side of plasma membrane immunological synapse extracellular exosome pericentriolar material membrane raft plasma membrane Biological process B cell receptor signaling pathway release of sequestered calcium ion into cytosol hemopoiesis phosphorylation transmembrane receptor protein tyrosine kinase signaling pathway positive regulation of T cell receptor signaling pathway T cell costimulation mitigation of host defenses by virus platelet activation T cell differentiation regulation of cell population proliferation cellular zinc ion homeostasis regulation of lymphocyte activation peptidyl-tyrosine autophosphorylation T cell receptor signaling pathway positive regulation of intrinsic apoptotic signaling pathway leukocyte migration positive regulation of T cell activation protein dephosphorylation innate immune response phosphatidylinositol phosphate biosynthetic process viral process protein phosphorylation activation of cysteine-type endopeptidase activity involved in apoptotic process cell migration peptidyl-tyrosine phosphorylation interleukin-7-mediated signaling pathway positive regulation of protein kinase B signaling cell differentiation positive regulation of heterotypic cell-cell adhesion positive regulation of leukocyte cell-cell adhesion Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 3932 16818 Ensembl ENSG00000182866 ENSMUSG00000000409 UniProt P06239 P06240 RefSeq (mRNA) NM_001042771 NM_005356 NM_001330468 NM_001162432 NM_001162433 NM_010693 RefSeq (protein) NP_001036236 NP_001317397 NP_005347 NP_001155904 NP_001155905 NP_034823 Location (UCSC) Chr 1: 32.25 – 32.29 Mb Chr 4: 129.44 – 129.47 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Tyrosin-protein kinase Lck (or lymphocyte-specific protein tyrosine kinase) is a 56 kDa protein that is found inside lymphocytes and encoded in the human by the LCK gene.^[5] The Lck is a member of Src kinase family (SFK) and is important for the activation of T-cell receptor (TCR) signaling in both naive T cells and effector T cells. The role of Lck is less prominent in the activation or in the maintenance of memory CD8 T cells in comparison to CD4 T cells. In addition, the constitutive activity of the mouse Lck homolog varies among memory T cell subsets. It seems that in mice, in the effector memory T cell (TEM) population, more than 50% of Lck is present in a constitutively active conformation, whereas less than 20% of Lck is present as active form in central memory T cells. These differences are due to differential regulation by SH2 domain–containing phosphatase-1 (Shp-1) and C-terminal Src kinase.^[6]

Lck is responsible for the initiation of the TCR signaling cascade inside the cell by phosphorylating immunoreceptor tyrosine-based activation motifs (ITAM) within the TCR-associated chains.

Lck can be found in different forms in immune cells: free in the cytosol or bound to the plasma membrane (PM) through myristoylation and palmitoylation. Due to the presence of the conserved CxxC motif (C20 and C23) in the zinc clasp structure, Lck is able to bind the cell surface coreceptors CD8 and\or CD4.

Bound and free Lck have different properties: free Lck has more pronounced kinase activity in comparison to bound Lck, and moreover, the free form produces a higher level of T cell activation.^[7] The reasons for these differences are not well understood yet.