QLS Guest Seminar - Wednesday, 27 November

[Quantitative Life Sciences]

QLS Guest Seminar - Wednesday, 27 November 11h00am

ICTP, Central Area, 2nd floor, SISSA Building, via Beirut 2

Speaker:     Marcel Prelogovic - Department of Physics, Faculty of 
Science University of Zagreb, Croatia

Title: Microtubule pivoting driven by cross-linking proteins leads to 
spindle assembly

Abstract:
During mitosis, microtubules form a spindle, which is responsible for 
the segregation of chromosomes. In yeast cells, the spindle has a 
rod-like structure and is made of microtubules emanating from two poles 
connected by cross-linking proteins. Microtubules self-organize into 
parallel or antiparallel bundles, depending on whether they grow from 
the same or two different poles and our goal here is understanding how 
such structures form. Our model includes thermally driven angular 
pivoting of microtubules around the poles and elastic forces between 
them mediated by cross-linking proteins, which can detach to and detach 
from microtubules, as well as move along them. The solutions of our 
model imply that the random motion of the microtubules allows them to 
find their pair, while the short-range interactions caused by the 
cross-linking proteins align them into bundles. Parallel bundling can 
occur in the presence of either passive crosslinkers or plus-end 
directed motors, while the formation of antiparallel bundles requires 
minus-end directed motors. The model predicts the average bundling time, 
which is in agreement with our experimental measurements. Additionally, 
for the case of antiparallel bundle formation, the model predicts that 
the velocity of the microtubules gliding along each other is the same as 
the velocity at which the motors move along the microtubules, and this 
was also confirmed experimentally. In conclusion, the main contributors 
to the formation of microtubule bundles are angular diffusion of 
microtubules around the poles allowing them to come into contact and 
short-range forces caused by cross-linking proteins that align them

Indico: http://indico.ictp.it/event/9199/

Everyone interested is most welcome to attend!

-- 
Erica Sarnataro
Group Secretary
Quantitative Life Sciences
The Abdus Salam International Centre for Theoretical Physics (ICTP)
Trieste,  Italy
Tel. +39-040-2240623
www.ictp.it/research/qls.aspx
e-mail: qls at ictp.it