7nx4
From Proteopedia
Crystal structure of the TG and EGF-like domains of ALK
Structural highlights
DiseaseALK_HUMAN Note=A chromosomal aberration involving ALK is found in a form of non-Hodgkin lymphoma. Translocation t(2;5)(p23;q35) with NPM1. The resulting chimeric NPM1-ALK protein homodimerize and the kinase becomes constitutively activated. The constitutively active fusion proteins are responsible for 5-10% of non-Hodgkin lymphomas. Note=A chromosomal aberration involving ALK is associated with inflammatory myofibroblastic tumors (IMTs). Translocation t(2;11)(p23;p15) with CARS; translocation t(2;4)(p23;q21) with SEC31A. Note=A chromosomal aberration involving ALK is associated with anaplastic large-cell lymphoma (ALCL). Translocation t(2;17)(p23;q25) with ALO17. Defects in ALK are the cause of susceptibility to neuroblastoma type 3 (NBLST3) [MIM:613014. Neuroblastoma is a common neoplasm of early childhood arising from embryonic cells that form the primitive neural crest and give rise to the adrenal medulla and the sympathetic nervous system.[1] [2] [3] Note=The ALK signaling pathway plays an important role in glioblastoma, the most common malignant brain tumor of adults and one of the most lethal cancers. It regulates both glioblastoma migration and growth. FunctionALK_HUMAN Neuronal orphan receptor tyrosine kinase that is essentially and transiently expressed in specific regions of the central and peripheral nervous systems and plays an important role in the genesis and differentiation of the nervous system. Transduces signals from ligands at the cell surface, through specific activation of the mitogen-activated protein kinase (MAPK) pathway. Phosphorylates almost exclusively at the first tyrosine of the Y-x-x-x-Y-Y motif. Following activation by ligand, ALK induces tyrosine phosphorylation of CBL, FRS2, IRS1 and SHC1, as well as of the MAP kinases MAPK1/ERK2 and MAPK3/ERK1. Acts as a receptor for ligands pleiotrophin (PTN), a secreted growth factor, and midkine (MDK), a PTN-related factor, thus participating in PTN and MDK signal transduction. PTN-binding induces MAPK pathway activation, which is important for the anti-apoptotic signaling of PTN and regulation of cell proliferation. MDK-binding induces phosphorylation of the ALK target insulin receptor substrate (IRS1), activates mitogen-activated protein kinases (MAPKs) and PI3-kinase, resulting also in cell proliferation induction. Drives NF-kappa-B activation, probably through IRS1 and the activation of the AKT serine/threonine kinase. Recruitment of IRS1 to activated ALK and the activation of NF-kappa-B are essential for the autocrine growth and survival signaling of MDK.[4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] Publication Abstract from PubMedAnaplastic lymphoma kinase (ALK)(1) and the related leukocyte tyrosine kinase (LTK)(2) are recently deorphanized receptor tyrosine kinases(3). Together with their activating cytokines, ALKAL1 and ALKAL2(4-6) (also called FAM150A and FAM150B or AUGbeta and AUGalpha, respectively), they are involved in neural development(7), cancer(7-9) and autoimmune diseases(10). Furthermore, mammalian ALK recently emerged as a key regulator of energy expenditure and weight gain(11), consistent with a metabolic role for Drosophila ALK(12). Despite such functional pleiotropy and growing therapeutic relevance(13,14), structural insights into ALK and LTK and their complexes with cognate cytokines have remained scarce. Here we show that the cytokine-binding segments of human ALK and LTK comprise a novel architectural chimera of a permuted TNF-like module that braces a glycine-rich subdomain featuring a hexagonal lattice of long polyglycine type II helices. The cognate cytokines ALKAL1 and ALKAL2 are monomeric three-helix bundles, yet their binding to ALK and LTK elicits similar dimeric assemblies with two-fold symmetry, that tent a single cytokine molecule proximal to the cell membrane. We show that the membrane-proximal EGF-like domain dictates the apparent cytokine preference of ALK. Assisted by these diverse structure-function findings, we propose a structural and mechanistic blueprint for complexes of ALK family receptors, and thereby extend the repertoire of ligand-mediated dimerization mechanisms adopted by receptor tyrosine kinases. Structural basis of cytokine-mediated activation of ALK family receptors.,De Munck S, Provost M, Kurikawa M, Omori I, Mukohyama J, Felix J, Bloch Y, Abdel-Wahab O, Bazan JF, Yoshimi A, Savvides SN Nature. 2021 Oct 13. pii: 10.1038/s41586-021-03959-5. doi:, 10.1038/s41586-021-03959-5. PMID:34646012[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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