1lkk
HUMAN P56-LCK TYROSINE KINASE SH2 DOMAIN IN COMPLEX WITH THE PHOSPHOTYROSYL PEPTIDE AC-PTYR-GLU-GLU-ILE (PYEEI PEPTIDE)
Structural highlights
DiseaseLCK_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. FunctionLCK_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 PubMedsrc homology 2 (SH2) domains are modules of about 100 amino acid residues and bind to phosphotyrosine-containing motifs in a sequence-specific manner. They play important roles in intracellular signal transduction and represent potential targets for pharmacological intervention. The protein tyrosine kinase p56lck is a member of the src family and is involved in T-cell activation. The crystal structure of its SH2 domain with an 11-residue peptide showed that the phosphotyrosine and the Ile residue at the pY + 3 position are recognized by the SH2 domain. We present here the crystal structure of the SH2 domain of human p56lck in complex with the short phosphotyrosyl peptide Ac-pTyr-Glu-Glu-Ile (pYEEI peptide) at 1.0 A resolution. The structural analysis at atomic resolution reveals that residue Arg134 (alphaA2), which interacts with the phosphotyrosine side-chain, is present in two conformations in the complex. The structure at 1.8 A resolution of the complex with the phosphotyrosyl peptide Ac-pTyr-Glu-Glu-Gly (pYEEG peptide), which is 11 fold less potent, shows another binding mode for the pY + 3 residue as well as rearrangements of the side-chain of Arg196 (EF3) and one of the water molecules at the base of the pY + 3 pocket. The structure of the complex with the short pYEEI peptide at atomic resolution represents a good starting point for the design and optimization of new inhibitors. Comparative structural analysis of many different inhibitor complexes will be an important component of this drug discovery process. Crystal structures of the human p56lck SH2 domain in complex with two short phosphotyrosyl peptides at 1.0 A and 1.8 A resolution.,Tong L, Warren TC, King J, Betageri R, Rose J, Jakes S J Mol Biol. 1996 Mar 1;256(3):601-10. PMID:8604142[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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