7mzw
From Proteopedia
Anaplastic lymphoma kinase (ALK) extracellular ligand binding region 673-1025
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 PubMedAnaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) that regulates important functions in the central nervous system(1,2). The ALK gene is a hotspot for chromosomal translocation events that result in several fusion proteins that cause a variety of human malignancies(3). Somatic and germline gain-of-function mutations in ALK were identified in paediatric neuroblastoma(4-7). ALK is composed of an extracellular region (ECR), a single transmembrane helix and an intracellular tyrosine kinase domain(8,9). ALK is activated by the binding of ALKAL1 and ALKAL2 ligands(10-14) to its ECR, but the lack of structural information for the ALK-ECR or for ALKAL ligands has limited our understanding of ALK activation. Here we used cryo-electron microscopy, nuclear magnetic resonance and X-ray crystallography to determine the atomic details of human ALK dimerization and activation by ALKAL1 and ALKAL2. Our data reveal a mechanism of RTK activation that allows dimerization by either dimeric (ALKAL2) or monomeric (ALKAL1) ligands. This mechanism is underpinned by an unusual architecture of the receptor-ligand complex. The ALK-ECR undergoes a pronounced ligand-induced rearrangement and adopts an orientation parallel to the membrane surface. This orientation is further stabilized by an interaction between the ligand and the membrane. Our findings highlight the diversity in RTK oligomerization and activation mechanisms. Mechanism for the activation of the anaplastic lymphoma kinase receptor.,Reshetnyak AV, Rossi P, Myasnikov AG, Sowaileh M, Mohanty J, Nourse A, Miller DJ, Lax I, Schlessinger J, Kalodimos CG Nature. 2021 Dec;600(7887):153-157. doi: 10.1038/s41586-021-04140-8. Epub 2021, Nov 24. PMID:34819673[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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