Atomic force microscopy reveals distinct protofilament-scale structural dynamics in depolymerizing microtubule arrays.

Autor:	Wijeratne SS; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114.; Department of Genetics, Harvard Medical School, Boston, MA 02115., Marchan MF; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114., Tresback JS; Center for Nanoscale Systems, Harvard University, Cambridge, MA 02139., Subramanian R; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114; radhika@molbio.mgh.harvard.edu.; Department of Genetics, Harvard Medical School, Boston, MA 02115.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2022 Feb 01; Vol. 119 (5).
DOI:	10.1073/pnas.2115708119
Abstrakt:	The dynamic reorganization of microtubule-based cellular structures, such as the spindle and the axoneme, fundamentally depends on the dynamics of individual polymers within multimicrotubule arrays. A major class of enzymes implicated in both the complete demolition and fine size control of microtubule-based arrays are depolymerizing kinesins. How different depolymerases differently remodel microtubule arrays is poorly understood. A major technical challenge in addressing this question is that existing optical or electron-microscopy methods lack the spatial-temporal resolution to observe the dynamics of individual microtubules within larger arrays. Here, we use atomic force microscopy (AFM) to image depolymerizing arrays at single-microtubule and protofilament resolution. We discover previously unseen modes of microtubule array destabilization by conserved depolymerases. We find that the kinesin-13 MCAK mediates asynchronous protofilament depolymerization and lattice-defect propagation, whereas the kinesin-8 Kip3p promotes synchronous protofilament depolymerization. Unexpectedly, MCAK can depolymerize the highly stable axonemal doublets, but Kip3p cannot. We propose that distinct protofilament-level activities underlie the functional dichotomy of depolymerases, resulting in either large-scale destabilization or length regulation of microtubule arrays. Our work establishes AFM as a powerful strategy to visualize microtubule dynamics within arrays and reveals how nanometer-scale substrate specificity leads to differential remodeling of micron-scale cytoskeletal structures. Competing Interests: The authors declare no competing interest. (Copyright © 2022 the Author(s). Published by PNAS.)
Databáze:	MEDLINE
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