Structure and mechanism of motors moving chromosomes in cell division

Supervisors: Julie WelburnTony Ly

Project Description:

Cell division is a highly regulated process that allows equal distribution of the genetic material to the daughter cells. Chromosome segregation requires the formation of a bipolar mitotic spindle composed of highly dynamic microtubule polymers, and assembly of a multi-protein structure termed the kinetochore to mediate attachments between the condensed chromosome and spindle microtubules. The capture, biorientation and alignment of chromosomes are critical to maintaining genomic integrity. The mitotic motor protein CENP-E, part of the kinesin superfamily, controls these processes. CENP-E transiently appears around centrosomes as a large ring, and then associates laterally with unaligned kinetochores close to the centrosomes. CENP-E moves them along spindle microtubules to the equator of the cell, until stable end-on attachments between the kinetochores and the opposing microtubules are generated (1). CENP-E is essential in maintaining kinetochore aligned during metaphase (2). However little is known about how CENP-E is activated and enables chromosome capture, movement and alignment.

The aim of this project is to understand how this nanoscale motor can move a micrometer-large structure such as a chromosome. The student will define (1) the molecular basis for how CENP-E is activated at centrosomes and how CENP-E is recruited to the kinetochore during mitosis. Relocalization of CENP-E throughout mitosis is dynamic. The student will analyze how CENP-E tethers to centrosomes and kinetochores during these stages, using cell biology, correlation light electron microscopy and mass spectrometry/proteomics analysis.
 In Aim (2), the student will define how CENP-E molecules are coordinated and move chromosomes. Using state of the state-of-the-art biochemical reconstitution approaches, they will analyze the molecular architecture of a CENP-E-kinetochore complex. They will then reconstitute motor-kinetochore complexes in vitro to study how CENP-E motors work together to move along microtubules and transport the kinetochore cargo. This work will have strong implications for our understanding of chromosome segregation and aneuploidy, and for the mechanism of molecular motors. 

This project enables a motivated Ph.D. student to apply biochemistry/mass spec, structural biology, in vitro reconstitution assays and single molecule microscopy and cell biology. It represents an outstanding opportunity for professional development and research. 

If you wish to apply for this project, please go to this link.