RT Journal Article
SR Electronic
T1 Distinct Protofilament-scale Dynamics Define the Differential Remodeling of Microtubule Arrays
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.12.22.423986
DO 10.1101/2020.12.22.423986
A1 Wijeratne, S. S.
A1 Marchan, M.
A1 Tresback, J. S.
A1 Subramanian, R.
YR 2020
UL http://biorxiv.org/content/early/2020/12/23/2020.12.22.423986.abstract
AB The intrinsic dynamic instability of microtubules and their control by associated enzymes, such as depolymerases, are essential for the organization of complex multi-microtubule arrays like spindle and axoneme. However, existing optical or electron-microscopy methods lack the spatial-temporal resolution to observe the dynamics of individual microtubules within arrays. We use Atomic Force Microscopy (AFM) to image depolymerizing arrays at single microtubule and protofilament resolution. We discover previously unseen modes of microtubule destabilization by conserved depolymerases. 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 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 and reveals how nanometer-scale substrate specificity leads to differential remodeling of micron-sized cytoskeletal structures.Competing Interest StatementThe authors have declared no competing interest.