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Lck  Protein, Antibody, ELISA Kit, cDNA Clone

Description: Active  
Expression host: Baculovirus-Insect Cells  
10043-H09B-50
10043-H09B-20
50 µg 
20 µg 
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Lck Related Area

Lck Related Pathways

Lck Summary & Protein Information

Lck Background

Gene Summary: This LCK gene is a member of the Src family of protein tyrosine kinases (PTKs). Lck is a key signaling molecule in the selection and maturation of developing T-cells. Lck contains N-terminal sites for myristylation and palmitylation, a PTK domain, and SH2 and SH3 domains which are involved in mediating protein-protein interactions with phosphotyrosine-containing and proline-rich motifs, respectively. The lck protein localizes to the plasma membrane and pericentrosomal vesicles, and binds to cell surface receptors, including CD4 and CD8, and other signaling molecules. Multiple alternatively spliced variants, encoding the same protein, have been described. [provided by RefSeq, Jul 2008]
General information above from NCBI
Catalytic activity: ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate. {ECO:0000255|PROSITE-ProRule:PRU10028}.
Enzyme regulation: ENZYME REGULATION: The relative activities of the inhibitory tyrosine-protein kinase CSK and the activating tyrosine-protein phosphatase PTPRC/CD45 determine the level of LCK activity. These interactions allow rapid and efficient activation of LCK in response to TCR stimulation. {ECO:0000269|PubMed:21917715}.
Subunit structure: Binds to the cytoplasmic domain of cell surface receptors, such as AXL, CD2, CD4, CD5, CD8, CD44, CD45 and CD122. Also binds to effector molecules, such as PI4K, VAV1, RASA1, FYB and to other protein kinases including CDK1, RAF1, ZAP70 and SYK. Binds to phosphatidylinositol 3'-kinase (PI3K) from T-lymphocytes through its SH3 domain and to the tyrosine phosphorylated form of KHDRBS1/p70 through its SH2 domain. Binds to HIV-1 Nef through its SH3 domain. This interaction inhibits its tyrosine-kinase activity. Interacts with herpes simplex virus 1 UL46; this interaction acitivates LCK. Interacts with SQSTM1. Interacts with phosphorylated LIME1. Interacts with CBLB and PTPRH. Interacts with RUNX3. Forms a signaling complex with EPHA1, PTK2B AND PI3-KINASE; upon activation by EFNA1 which may regulate T-lymphocyte migration. Associates with ZAP70 and RHOH; these interactions allow LCK-mediated RHOH and CD3 subunit phosphorylation in the presence of functional ZAP70. Interacts with UNC119; this interaction plays a crucial role in activation of LCK. {ECO:0000269|PubMed:12837766, ECO:0000269|PubMed:14610044, ECO:0000269|PubMed:14610046, ECO:0000269|PubMed:14757743, ECO:0000269|PubMed:17634955, ECO:0000269|PubMed:23946459, ECO:0000269|PubMed:7504174, ECO:0000269|PubMed:7852312, ECO:0000269|PubMed:8618896, ECO:0000269|PubMed:8794306, ECO:0000269|PubMed:9178760}.
Domain: The SH2 domain mediates interaction with SQSTM1. Interaction is regulated by Ser-59 phosphorylation.
Subcellular location: Cytoplasm {ECO:0000269|PubMed:12218089}. Cell membrane {ECO:0000269|PubMed:12218089}; Lipid-anchor {ECO:0000269|PubMed:12218089}; Cytoplasmic side {ECO:0000269|PubMed:12218089}. Note=Present in lipid rafts in an inactive form.
Tissue specificity: Expressed specifically in lymphoid cells.
Post-translational: Autophosphorylated on Tyr-394, increasing enzymatic activity, this site is dephosphorylated by PTN22. Phosphorylated on Tyr-505 by CSK, decreasing activity. Dephosphorylated by PTPRC/CD45. Dephosphorylation at Tyr-394 by PTPN2 negatively regulates T-cell receptor signaling. {ECO:0000269|PubMed:1639064, ECO:0000269|PubMed:22080863, ECO:0000269|PubMed:8139546, ECO:0000269|PubMed:8631775}.; Myristoylation is required prior to palmitoylation. {ECO:0000250}.; Palmitoylation regulates subcellular location. {ECO:0000250}.
Involvement in disease: DISEASE: Note=A chromosomal aberration involving LCK is found in leukemias. Translocation t(1;7)(p34;q34) with TCRB.; DISEASE: Immunodeficiency 22 (IMD22) [MIM:615758]: A primary immunodeficiency characterized by T-cell dysfunction. Affected individuals present with lymphopenia, recurrent infections, severe diarrhea, and failure to thrive. {ECO:0000269|PubMed:22985903}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Sequence similarity: Belongs to the protein kinase superfamily. Tyr protein kinase family. SRC subfamily. {ECO:0000255|PROSITE-ProRule:PRU00159}.; Contains 1 protein kinase domain. {ECO:0000255|PROSITE-ProRule:PRU00159}.; Contains 1 SH2 domain. {ECO:0000255|PROSITE-ProRule:PRU00191}.; Contains 1 SH3 domain. {ECO:0000255|PROSITE-ProRule:PRU00192}.
General information above from UniProt

Protein kinases are critically involved in signaling pathways that regulate cell growth, differentiation, activation, and survival. Initially identified as a T-cell specific member of the Src family of protein tyrosine kinases, Lck has become the object of intensive investigations which have revealed a key role for this kinase in the central processes controlling T-cell development, activation, proliferation and survival. Lck is expressed specifically in lymphoid cells. It contains one protein kinase domain, one SH2 domain, and one SH3 domain. It is associated with a variety of cell surface receptors and is critical for signal transduction from the T-cell antigen receptor (TCR). Consequently, Lck is targeted by regulatory proteins of T-lymphotropic viruses, especially by the Herpesvirus saimiri (HVS) tyrosine kinase interacting protein (Tip). This oncoprotein physically interacts with Lck in HVS transformed T cells and has an impact on its catalytic activity. Together with the identification of defects in the regulation of Lck expression or activity in T-cell leukemias, suggests that dysregulation of Lck might play a role in neoplastic transformation. However, under certain conditions Lck is also involved in the induction of apoptosis. This chemosensitizing effect of Lck is independent of T-cell receptor signaling and does not require the kinase activity of Lck. The findings demonstrate that Lck might be part of two independent signaling pathways leading to either cell proliferation or apoptosis.

Lck Alternative Name

LSK,YT16,IMD22,p56lck,pp58lck, [homo-sapiens]
LCK,LSK,p56lck,pp58lck,RP4-675E8.4,YT16, [human]
Hck-3,Lck,lck>,Lsk,Lskt,p56<,p56Lck,RP23-209C6.8, [mouse]
Lsk,Lskt,Hck-3,p56Lck,p56<,lck>, [mus-musculus]

Lck Related Studies

  • Majolini MB, et al. (1999) Dysregulation of the protein tyrosine kinase LCK in lymphoproliferative disorders and in other neoplasias. Leuk Lymphoma. 35(3-4): 245-54.
  • Isakov N, et al. (2000) Lck protein tyrosine kinase is a key regulator of T-cell activation and a target for signal intervention by Herpesvirus saimiri and other viral gene products. Eur J Biochem. 267(12): 3413-21.
  • Heyninck K, et al. (2006) A novel link between Lck, Bak expression and chemosensitivity. Oncogene. 25(12): 1693-5.
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