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(New page: ==Abl 1b Regulatory Module 'inhibiting state'== <StructureSection load='6amv' size='340' side='right' caption='6amv, 20 NMR models' scene=''> == Structur...)
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Revision as of 07:02, 11 October 2017
proteopedia linkproteopedia linkAbl 1b Regulatory Module 'inhibiting state'
Structural highlights
Disease[ABL1_HUMAN] Note=A chromosomal aberration involving ABL1 is a cause of chronic myeloid leukemia. Translocation t(9;22)(q34;q11) with BCR. The translocation produces a BCR-ABL found also in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Function[ABL1_HUMAN] Non-receptor tyrosine-protein kinase that plays a role in many key processes linked to cell growth and survival such as cytoskeleton remodeling in response to extracellular stimuli, cell motility and adhesion, receptor endocytosis, autophagy, DNA damage response and apoptosis. Coordinates actin remodeling through tyrosine phosphorylation of proteins controlling cytoskeleton dynamics like WASF3 (involved in branch formation); ANXA1 (involved in membrane anchoring); DBN1, DBNL, CTTN, RAPH1 and ENAH (involved in signaling); or MAPT and PXN (microtubule-binding proteins). Phosphorylation of WASF3 is critical for the stimulation of lamellipodia formation and cell migration. Involved in the regulation of cell adhesion and motility through phosphorylation of key regulators of these processes such as BCAR1, CRK, CRKL, DOK1, EFS or NEDD9. Phosphorylates multiple receptor tyrosine kinases and more particularly promotes endocytosis of EGFR, facilitates the formation of neuromuscular synapses through MUSK, inhibits PDGFRB-mediated chemotaxis and modulates the endocytosis of activated B-cell receptor complexes. Other substrates which are involved in endocytosis regulation are the caveolin (CAV1) and RIN1. Moreover, ABL1 regulates the CBL family of ubiquitin ligases that drive receptor down-regulation and actin remodeling. Phosphorylation of CBL leads to increased EGFR stability. Involved in late-stage autophagy by regulating positively the trafficking and function of lysosomal components. ABL1 targets to mitochondria in response to oxidative stress and thereby mediates mitochondrial dysfunction and cell death. ABL1 is also translocated in the nucleus where it has DNA-binding activity and is involved in DNA-damage response and apoptosis. Many substrates are known mediators of DNA repair: DDB1, DDB2, ERCC3, ERCC6, RAD9A, RAD51, RAD52 or WRN. Activates the proapoptotic pathway when the DNA damage is too severe to be repaired. Phosphorylates TP73, a primary regulator for this type of damage-induced apoptosis. Phosphorylates the caspase CASP9 on 'Tyr-153' and regulates its processing in the apoptotic response to DNA damage. Phosphorylates PSMA7 that leads to an inhibition of proteasomal activity and cell cycle transition blocks. ABL1 acts also as a regulator of multiple pathological signaling cascades during infection. Several known tyrosine-phosphorylated microbial proteins have been identified as ABL1 substrates. This is the case of A36R of Vaccinia virus, Tir (translocated intimin receptor) of pathogenic E.coli and possibly Citrobacter, CagA (cytotoxin-associated gene A) of H.pylori, or AnkA (ankyrin repeat-containing protein A) of A.phagocytophilum. Pathogens can highjack ABL1 kinase signaling to reorganize the host actin cytoskeleton for multiple purposes, like facilitating intracellular movement and host cell exit. Finally, functions as its own regulator through autocatalytic activity as well as through phosphorylation of its inhibitor, ABI1.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] Publication Abstract from PubMedThe activity of protein kinases is often regulated in an intramolecular fashion by signaling domains, which feature several phosphorylation or protein-docking sites. How kinases integrate such distinct binding and signaling events to regulate their activities is unclear, especially in quantitative terms. We used NMR spectroscopy to show how structural elements within the Abl regulatory module (RM) synergistically generate a multilayered allosteric mechanism that enables Abl kinase to function as a finely tuned switch. We dissected the structure and energetics of the regulatory mechanism to precisely measure the effects of various activating or inhibiting stimuli on Abl kinase activity. The data provide a mechanistic basis explaining genetic observations and reveal a previously unknown activator region within Abl. Our findings show that drug-resistance mutations in the Abl RM exert their allosteric effect by promoting the activated state of Abl and not by decreasing the drug affinity for the kinase. Atomic view of the energy landscape in the allosteric regulation of Abl kinase.,Saleh T, Rossi P, Kalodimos CG Nat Struct Mol Biol. 2017 Sep 25. doi: 10.1038/nsmb.3470. PMID:28945248[23] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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