A TOG:αβ-tubulin complex structure reveals conformation-based mechanisms for a microtubule polymerase.
Stu2p/XMAP215/Dis1 family proteins are evolutionarily conserved regulatory factors that use αβ-tubulin-interacting tumor overexpressed gene (TOG) domains to catalyze fast microtubule growth. Catalysis requires that these polymerases discriminate between unpolymerized and polymerized forms of αβ-tubulin, but the mechanism by which they do so has remained unclear. Here, we report the structure ... of the TOG1 domain from Stu2p bound to yeast αβ-tubulin. TOG1 binds αβ-tubulin in a way that excludes equivalent binding of a second TOG domain. Furthermore, TOG1 preferentially binds a curved conformation of αβ-tubulin that cannot be incorporated into microtubules, contacting α- and β-tubulin surfaces that do not participate in microtubule assembly. Conformation-selective interactions with αβ-tubulin explain how TOG-containing polymerases discriminate between unpolymerized and polymerized forms of αβ-tubulin and how they selectively recognize the growing end of the microtubule.
Mesh Terms:
Crystallography, X-Ray, Gene Expression Regulation, Neoplastic, Genes, Neoplasm, Microtubule-Associated Proteins, Microtubules, Polymerization, Protein Conformation, Protein Structure, Tertiary, Saccharomyces cerevisiae Proteins, Tubulin
Crystallography, X-Ray, Gene Expression Regulation, Neoplastic, Genes, Neoplasm, Microtubule-Associated Proteins, Microtubules, Polymerization, Protein Conformation, Protein Structure, Tertiary, Saccharomyces cerevisiae Proteins, Tubulin
Science
Date: Aug. 17, 2012
PubMed ID: 22904013
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