5y4e
Crystal Structure of AnkB Ankyrin Repeats R8-14 in complex with autoinhibition segment AI-b
Structural highlights
DiseaseANK2_HUMAN Romano-Ward syndrome. Long QT syndrome 4 (LQT4) [MIM:600919: A heart disorder characterized by a prolonged QT interval on the ECG and polymorphic ventricular arrhythmias. They cause syncope and sudden death in response to exercise or emotional stress, and can present with a sentinel event of sudden cardiac death in infancy. Long QT syndrome type 4 shows many atypical features compared to classical long QT syndromes, including pronounced sinus bradycardia, polyphasic T waves and atrial fibrillation. Cardiac repolarization defects may be not as severe as in classical LQT syndromes and prolonged QT interval on EKG is not a consistent feature. Note=The disease is caused by mutations affecting the gene represented in this entry.[1] [2] FunctionANK2_HUMAN In skeletal muscle, required for proper localization of DMD and DCTN4 and for the formation and/or stability of a special subset of microtubules associated with costameres and neuromuscular junctions (By similarity). Attaches integral membrane proteins to cytoskeletal elements. Also binds to cytoskeletal proteins. Required for coordinate assembly of Na/Ca exchanger, Na/K ATPase and InsP3 receptor at sarcoplasmic reticulum sites in cardiomyocytes. Required for the coordinated expression of the Na/K ATPase, Na/Ca exchanger and beta-2-spectrin (SPTBN1) in the inner segment of rod photoreceptors. Required for expression and targeting of SPTBN1 in neonatal cardiomyocytes and for the regulation of neonatal cardiomyocyte contraction rate.[3] Publication Abstract from PubMedAnkyrins together with their spectrin partners are the master organizers of micron-scale membrane domains in diverse tissues. The 24 ankyrin (ANK) repeats of ankyrins bind to numerous membrane proteins, linking them to spectrin-based cytoskeletons at specific membrane microdomains. The accessibility of the target binding groove of ANK repeats must be regulated to achieve spatially defined functions of ankyrins/target complexes in different tissues, though little is known in this regard. Here we systemically investigated the autoinhibition mechanism of ankyrin-B/G by combined biochemical, biophysical and structural biology approaches. We discovered that the entire ANK repeats are inhibited by combinatorial and quasi-independent bindings of multiple disordered segments located in the ankyrin-B/G linkers and tails, suggesting a mechanistic basis for differential regulations of membrane target bindings by ankyrins. In addition to elucidating the autoinhibition mechanisms of ankyrins, our study may also shed light on regulations on target bindings by other long repeat-containing proteins. Autoinhibition of ankyrin-B/G membrane target bindings by intrinsically disordered segments from the tail regions.,Chen K, Li J, Wang C, Wei Z, Zhang M Elife. 2017 Aug 25;6. pii: e29150. doi: 10.7554/eLife.29150. PMID:28841137[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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