TY - JOUR
T1 - The microtubule-severing protein UNC-45A preferentially binds to curved microtubules and counteracts the microtubule-straightening effects of Taxol
AU - Hoshino, Asumi
AU - Clemente, Valentino
AU - Shetty, Mihir
AU - Castle, Brian
AU - Odde, David
AU - Bazzaro, Martina
N1 - Publisher Copyright:
© 2023 The Authors
PY - 2023/11
Y1 - 2023/11
N2 - 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.
AB - 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.
KW - UNC-45A
KW - microtubule curvature
KW - microtubules
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U2 - 10.1016/j.jbc.2023.105355
DO - 10.1016/j.jbc.2023.105355
M3 - Article
C2 - 37858676
AN - SCOPUS:85175606587
SN - 0021-9258
VL - 299
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 11
M1 - 105355
ER -