The microtubule-severing protein UNC-45A preferentially binds to curved microtubules and counteracts the microtubule-straightening effects of Taxol

Asumi Hoshino, Valentino Clemente, Mihir J Shetty, Brian Castle, David Odde, Martina Bazzaro

Research output: Contribution to journalArticlepeer-review

Abstract

Uncoordinated protein 45A (UNC-45A) is the only known ATP-independent microtubule (MT)-severing protein. Thus, it severs MTs via a novel mechanism. In vitro and in cells, UNC-45A–mediated MT severing is preceded by the appearance of MT bends. While MTs are stiff biological polymers, in cells, they often curve, and the result of this curving can be breaking off. The contribution of MT-severing proteins on MT lattice curvature is largely undefined. Here, we show that UNC-45A curves MTs. Using in vitro biophysical reconstitution and total internal fluorescence microscopy analysis, we show that UNC-45A is enriched in the areas where MTs are curved versus the areas where MTs are straight. In cells, we show that UNC-45A overexpression increases MT curvature and its depletion has the opposite effect. We also show that this effect occurs is independent of actomyosin contractility. Lastly, we show for the first time that in cells, Paclitaxel straightens MTs, and that UNC-45A can counteracts the MT-straightening effects of the drug.

Original languageEnglish (US)
Article number105355
JournalJournal of Biological Chemistry
Volume299
Issue number11
DOIs
StatePublished - Nov 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors

Keywords

  • UNC-45A
  • microtubule curvature
  • microtubules

PubMed: MeSH publication types

  • Journal Article

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