Microtubules (MTs) are cytoskeletal fibers that undergo dynamic instability (DI), a remarkable process involving phases of growth and shortening separated by stochastic transitions called catastrophe and rescue. Dissecting DI mechanism(s) requires first characterizing and quantifying these dynamics, a subjective process that often ignores complexity in MT behavior. We present a Statistical Tool for Automated Dynamic Instability Analysis (STADIA) that identifies and quantifies not only growth and shortening, but also a category of intermediate behaviors that we term “stutters.” During stutters, the rate of MT length change tends to be smaller in magnitude than during typical growth or shortening phases. Quantifying stutters and other behaviors with STADIA demonstrates that stutters precede most catastrophes in our in vitro experiments and dimer-scale MT simulations, suggesting that stutters are mechanistically involved in catastrophes. Related to this idea, we show that the anticatastrophe factor CLASP2γ works by promoting the return of stuttering MTs to growth. STADIA enables more comprehensive and data-driven analysis of MT dynamics compared with previous methods. The treatment of stutters as distinct and quantifiable DI behaviors provides new opportunities for analyzing mechanisms of MT dynamics and their regulation by binding proteins.
|Original language||English (US)|
|Journal||Molecular biology of the cell|
|State||Published - Mar 1 2022|
Bibliographical noteFunding Information:
This work was supported by National Science Foundation (NSF) grants MCB-1244593 to H.V.G. and M.A., MCB-1817966 to H.V.G., and MCB-1817632 to E.M.J., National Institutes of Health (NIH) grant R35GM119552 to M.Z., and National Institutes of Health Integrated Biological Systems Training in Oncology training grant T32CA119925 to E.J.L. M.Z. also acknowledges the Searle Scholars Program. Portions of the work were also supported by funding from the University of Massachusetts Amherst (A.J.M.), NSF-GFRP DGE-1313583 (K.S.M.), and a fellowship from the Dolores Zohrab Liebmann Fund (S.M.M.). We thank the members of the Goodson laboratory and the Chicago Cytoskeleton community for their insightful discussions.
© 2022 Mahserejian, Scripture, et al.