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Mal3 CH domain homology model and mammalian tubulin (2XRP) docked into the 8.6-Angstrom cryo-EM map of Mal3-GTPgammaS-microtubulesMal3 CH domain homology model and mammalian tubulin (2XRP) docked into the 8.6-Angstrom cryo-EM map of Mal3-GTPgammaS-microtubules
Structural highlights
Function[MAL3_SCHPO] May play a role in regulating the integrity of microtubules possibly by influencing their stability. Involved in an anchoring mechanism to maintain tea2 and tip1 at growing microtubule ends. Strongly stimulates the ATPase activity of tea2.[1] [2] Publication Abstract from PubMedGrowing microtubule ends serve as transient binding platforms for essential proteins that regulate microtubule dynamics and their interactions with cellular substructures. End-binding proteins (EBs) autonomously recognize an extended region at growing microtubule ends with unknown structural characteristics and then recruit other factors to the dynamic end structure. Using cryo-electron microscopy, subnanometer single-particle reconstruction, and fluorescence imaging, we present a pseudoatomic model of how the calponin homology (CH) domain of the fission yeast EB Mal3 binds to the end regions of growing microtubules. The Mal3 CH domain bridges protofilaments except at the microtubule seam. By binding close to the exchangeable GTP-binding site, the CH domain is ideally positioned to sense the microtubule's nucleotide state. The same microtubule-end region is also a stabilizing structural cap protecting the microtubule from depolymerization. This insight supports a common structural link between two important biological phenomena, microtubule dynamic instability and end tracking. EBs recognize a nucleotide-dependent structural cap at growing microtubule ends.,Maurer SP, Fourniol FJ, Bohner G, Moores CA, Surrey T Cell. 2012 Apr 13;149(2):371-82. PMID:22500803[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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