| Structural highlights
Disease
[LCK_HUMAN] Severe combined immunodeficiency due to LCK deficiency. Note=A chromosomal aberration involving LCK is found in leukemias. Translocation t(1;7)(p34;q34) with TCRB.
Function
[LCK_HUMAN] 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 tyrosines 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.[1] [2] [3] [4] [5] [6]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
In cytosolic Src-type tyrosine kinases the Src-type homology 3 (SH3) domain binds to an internal proline-rich motif and the presence or the absence of this interaction modulates the kinase enzymatic activity. The Src-type kinase Lck plays an important role during T-cell activation and development, since it phosphorylates the T-cell antigen receptor in an early step of the activation pathway. We have determined the crystal structure of the SH3 domain from Lck kinase at a near-atomic resolution of 1.0 A. Unexpectedly, the Lck-SH3 domain forms a symmetrical homodimer in the crystal and the dimer comprises two identical zinc-binding sites in the interface. The atomic interactions formed across the dimer interface resemble strikingly those observed between SH3 domains and their canonical proline-rich ligands, since almost identical residues participate in both contacts. Ultracentrifugation experiments confirm that in the presence of zinc ions, the Lck-SH3 domain also forms dimers in solution. The Zn(2+) dissociation constant from the Lck-SH3 dimer is estimated to be lower than 100 nM. Moreover, upon addition of a proline-rich peptide with a sequence corresponding to the recognition segment of the herpesviral regulatory protein Tip, competition between zinc-induced homodimerization and binding of the peptide can be detected by both fluorescence spectroscopy and analytical ultracentrifugation. These results suggest that in vivo, too, competition between Lck-SH3 homodimerization and binding of regulatory proline-rich sequence motifs possibly represents a novel mechanism by which kinase activity is modulated. Because the residues that form the zinc-binding site are highly conserved among Lck orthologues but not in other Src-type kinases, the mechanism might be peculiar to Lck and to its role in the initial steps of T-cell activation.
Crystal structure analysis and solution studies of human Lck-SH3; zinc-induced homodimerization competes with the binding of proline-rich motifs.,Romir J, Lilie H, Egerer-Sieber C, Bauer F, Sticht H, Muller YA J Mol Biol. 2007 Feb 2;365(5):1417-28. Epub 2006 Oct 21. PMID:17118402[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Gelkop S, Gish GD, Babichev Y, Pawson T, Isakov N. T cell activation-induced CrkII binding to the Zap70 protein tyrosine kinase is mediated by Lck-dependent phosphorylation of Zap70 tyrosine 315. J Immunol. 2005 Dec 15;175(12):8123-32. PMID:16339550
- ↑ Mason LH, Willette-Brown J, Taylor LS, McVicar DW. Regulation of Ly49D/DAP12 signal transduction by Src-family kinases and CD45. J Immunol. 2006 Jun 1;176(11):6615-23. PMID:16709819
- ↑ Goh YM, Cinghu S, Hong ET, Lee YS, Kim JH, Jang JW, Li YH, Chi XZ, Lee KS, Wee H, Ito Y, Oh BC, Bae SC. Src kinase phosphorylates RUNX3 at tyrosine residues and localizes the protein in the cytoplasm. J Biol Chem. 2010 Mar 26;285(13):10122-9. doi: 10.1074/jbc.M109.071381. Epub 2010, Jan 25. PMID:20100835 doi:10.1074/jbc.M109.071381
- ↑ Collins M, Tremblay M, Chapman N, Curtiss M, Rothman PB, Houtman JC. The T cell receptor-mediated phosphorylation of Pyk2 tyrosines 402 and 580 occurs via a distinct mechanism than other receptor systems. J Leukoc Biol. 2009 Dec 22. PMID:20028775 doi:jlb.0409227
- ↑ Wang H, Zeng X, Fan Z, Lim B. RhoH modulates pre-TCR and TCR signalling by regulating LCK. Cell Signal. 2011 Jan;23(1):249-58. doi: 10.1016/j.cellsig.2010.09.009. Epub 2010, Sep 16. PMID:20851766 doi:10.1016/j.cellsig.2010.09.009
- ↑ Scales TM, Derkinderen P, Leung KY, Byers HL, Ward MA, Price C, Bird IN, Perera T, Kellie S, Williamson R, Anderton BH, Reynolds CH. Tyrosine phosphorylation of tau by the SRC family kinases lck and fyn. Mol Neurodegener. 2011 Jan 26;6:12. doi: 10.1186/1750-1326-6-12. PMID:21269457 doi:10.1186/1750-1326-6-12
- ↑ Romir J, Lilie H, Egerer-Sieber C, Bauer F, Sticht H, Muller YA. Crystal structure analysis and solution studies of human Lck-SH3; zinc-induced homodimerization competes with the binding of proline-rich motifs. J Mol Biol. 2007 Feb 2;365(5):1417-28. Epub 2006 Oct 21. PMID:17118402 doi:10.1016/j.jmb.2006.10.058
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