APS March Meeting 2018
Volume 63, Number 1
Monday–Friday, March 5–9, 2018;
Los Angeles, California
Session F51: Self Organization in the Cytoskeleton I
11:15 AM–2:15 PM,
Tuesday, March 6, 2018
LACC
Room: 511C
Sponsoring
Units:
DBIO GSOFT
Chair: M. Betterton, Univ of Colorado - Boulder
Abstract ID: BAPS.2018.MAR.F51.6
Abstract: F51.00006 : Microtubule cryptography: the effects of tubulin diversity on polymer structure, dynamics and readout by cellular effectors
12:15 PM–12:51 PM
Abstract
Presenter:
Antonina Roll-Mecak
(National Institutes of Health)
Author:
Antonina Roll-Mecak
(National Institutes of Health)
Microtubules are essential non-covalent polymers composed of -tubulin
subunits. Deceptively uniform ultrastructurally, microtubules are mosaic and
contain multiple tubulin isoforms functionalized with abundant posttranslational
modifications. Tubulin isoforms and posttranslational modifications vary widely
between cell types and their patterns are stereotyped, suggesting roles in spatial
and temporal control. An increasing body of evidence supports the hypothesis
that the combinatorial information expressed through tubulin genetic and
chemical diversity controls microtubule dynamics, mechanics and interactions
with microtubule effectors and thus constitutes a “tubulin code”. Although
discovered over thirty years ago, a mechanistic understanding of the tubulin code
has remained elusive. I will present two studies from my lab that illustrate how
the tubulin code can regulate microtubule properties in cis, by directly affecting
microtubule structure and dynamic instability, and in trans, by precisely
controlling the activity of a microtubule effector, a microtubule severing enzyme.
(1) I will discuss our recent data that reveals how varying tubulin isoform
composition proportionally tunes microtubule dynamic parameters and (2) I will
discuss our data that demonstrates that glutamylation, a posttranslational
modification that involves the addition of variable numbers of glutamates to the
intrinsically disordered tubulin C-terminal tails acts as a rheostat and tunes
microtubule severing as a function of glutamate number added per tubulin.
Unexpectedly, glutamylation is a non-linear biphasic tuner and becomes
inhibitory beyond a threshold. Furthermore, the inhibitory effect of localized
glutamylation propagates across neighboring microtubules, modulating severing
in trans. This work provided the first quantitative evidence for a graded, spatially
controlled response to a tubulin posttranslational modification and constitutes an
essential step towards understanding how the cell interprets the tubulin code.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.MAR.F51.6