7lrz | pdb_00007lrz
Structure of the Human ALK GRD
Structural highlights
Disease[ALK_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. Function[ALK_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 PubMedThe proto-oncogene ALK encodes anaplastic lymphoma kinase, a receptor tyrosine kinase that is expressed primarily in the developing nervous system. After development, ALK activity is associated with learning and memory(1) and controls energy expenditure, and inhibition of ALK can prevent diet-induced obesity(2). Aberrant ALK signalling causes numerous cancers(3). In particular, full-length ALK is an important driver in paediatric neuroblastoma(4,5), in which it is either mutated(6) or activated by ligand(7). Here we report crystal structures of the extracellular glycine-rich domain (GRD) of ALK, which regulates receptor activity by binding to activating peptides(8,9). Fusing the ALK GRD to its ligand enabled us to capture a dimeric receptor complex that reveals how ALK responds to its regulatory ligands. We show that repetitive glycines in the GRD form rigid helices that separate the major ligand-binding site from a distal polyglycine extension loop (PXL) that mediates ALK dimerization. The PXL of one receptor acts as a sensor for the complex by interacting with a ligand-bound second receptor. ALK activation can be abolished through PXL mutation or with PXL-targeting antibodies. Together, these results explain how ALK uses its atypical architecture for its regulation, and suggest new therapeutic opportunities for ALK-expressing cancers such as paediatric neuroblastoma. Structural basis for ligand reception by anaplastic lymphoma kinase.,Li T, Stayrook SE, Tsutsui Y, Zhang J, Wang Y, Li H, Proffitt A, Krimmer SG, Ahmed M, Belliveau O, Walker IX, Mudumbi KC, Suzuki Y, Lax I, Alvarado D, Lemmon MA, Schlessinger J, Klein DE Nature. 2021 Dec;600(7887):148-152. doi: 10.1038/s41586-021-04141-7. Epub 2021, Nov 24. PMID:34819665[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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