6m3r | pdb_00006m3r
Crystal structure of AnkG/beta4-spectrin complex
Structural highlights
FunctionANK3_RAT Membrane-cytoskeleton linker. May participate in the maintenance/targeting of ion channels and cell adhesion molecules at the nodes of Ranvier and axonal initial segments. In skeletal muscle, required for costamere localization of DMD and betaDAG1 (By similarity). Regulates KCNA1 channel activity in function of dietary Mg(2+) levels, and thereby contributes to the regulation of renal Mg(2+) reabsorption (By similarity).[UniProtKB:G5E8K5] Publication Abstract from PubMedAnkyrins (encoded by ANK1/2/3 corresponding to Ankyrin-R/B/G or AnkR/B/G), via binding to spectrins, connect plasma membranes with actin cytoskeleton to maintain mechanical strengths and to modulate excitabilities of diverse cells such as neurons, muscle cells, and erythrocytes. Cellular and genetic evidences suggest that each isoform of ankyrins pairs with a specific beta-spectrin in discrete subcellular membrane microdomains for distinct functions, though the molecular mechanisms underlying such ankyrin/beta-spectrin pairings are unknown. In this study, we discover that a conserved and short extension N-terminal to the ZU5N-ZU5C-UPA tandem (exZZU) is critical for each ankyrin to bind to beta-spectrins with high affinities. Structures of AnkB/G exZZU in complex with spectrin repeats13-15 of beta2/beta4-spectrins solved here reveal that the extension sequence of exZZU forms an additional beta-strand contributing to the structural stability and enhanced affinity of each ZU5N/spectrin repeat interaction. The complex structures further reveal that the UPA domain of exZZU directly participates in spectrin binding. Formation of the exZZU supramodule juxtaposes the ZU5N and UPA domains for simultaneous interacting with spectrin repeats 14 and 15. However, our biochemical and structural investigations indicate that the direct and strong interactions between ankyrins and beta-spectrins do not appear to determine their pairing specificities. Therefore, there likely exists additional mechanism(s) for modulating functional pairings between ankyrins and beta-spectrins in cells. Structural Basis Underlying Strong Interactions between Ankyrins and Spectrins.,Li J, Chen K, Zhu R, Zhang M J Mol Biol. 2020 Apr 27. pii: S0022-2836(20)30321-1. doi:, 10.1016/j.jmb.2020.04.023. PMID:32353364[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||
