Α1A and α1C form microtubules to display distinct properties mainly mediated by their C-terminal tails. (5th October 2021)

• Record Type: Journal Article
• Authors: Diao, Lei; Liu, Ming-Yi; Song, Yin-Long; Zhang, Xu; Liang, Xin; Bao, Lan
• Editors: Yao, Xuebiao
• Is Part Of: Journal of molecular cell biology. Volume 13:Number 12(2021)
• Page Start: 864
• Page End: 875
• Publication Date: 2021-10-05
• Subjects: α-tubulin isotype -- microtubule dynamics -- TIRF; Molecular biology -- Periodicals; 571.605
• DOI: 10.1093/jmcb/mjab062
• Languages: English
• ISSNs: 1674-2788

Abstract

Abstract: Microtubules consisting of α/β-tubulin dimers play critical roles in cells. More than seven genes encode α-tubulin in vertebrates. However, the property of microtubules composed of different α-tubulin isotypes is largely unknown. Here, we purified recombinant tubulin heterodimers of mouse α-tubulin isotypes including α1A and α1C with β-tubulin isotype β2A. In vitro microtubule reconstitution assay detected that α1C/β2A microtubules grew faster and underwent catastrophe less frequently than α1A/β2A microtubules. Generation of chimeric tail-swapped and point-mutation tubulins revealed that the carboxyl-terminal (C-terminal) tails of α-tubulin isotypes largely accounted for the differences in polymerization dynamics of α1A/β2A and α1C/β2A microtubules. Kinetics analysis showed that in comparison to α1A/β2A microtubules, α1C/β2A microtubules displayed higher on-rate, lower off-rate, and similar GTP hydrolysis rate at the plus-end, suggesting a contribution of higher plus-end affinity to faster growth and less frequent catastrophe of α1C/β2A microtubules. Furthermore, EB1 had a higher binding ability to α1C/β2A microtubules than to α1A/β2A ones, which could also be attributed to the difference in the C-terminal tails of these two α-tubulin isotypes. Thus, α-tubulin isotypes diversify microtubule properties, which, to a great extent, could be accounted by their C-terminal tails.