α1A and C form microtubules to display distinct properties mainly mediated by their C-terminal tails

• 作者: Lei Diao Ming-Yi Liu Yin-Long Song Xu Zhang Xin Liang Lan Bao
• 来源期刊: 分子细胞生物学报（英文版）
• 年，卷（期）: 2021,（12）
• 所属期刊栏目: Articles
• 页码范围: 864-875
• 页数: 12页
• 语种: 英文
• DOI: 10.1093/jmcb/mjab062

摘要

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 recombi-nant tubulin heterodimers of mouse α-tubulin isotypes including α1A and α1C with β-tubulin isotype β2A.In vitro microtubule re-constitution 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 microtu-bules.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 micro-tubules than to α1A/β2A ones,which could also be attributed to the difference in the C-terminal tails of these two α-tubulin iso-types.Thus,α-tubulin isotypes diversify microtubule properties,which,to a great extent,could be accounted by their C-terminal tails.