The Johns Hopkins University

Whiting School of Engineering

Department of Electrical and Computer Engineering

A Novel Mechanosensory Feedback System Controls Cell

Shape Progression During Cytokinesis

A Dissertation Defense by

Janet Effler

Graduate Research Assistant

Electrical and Computer Engineering

Abstract:

Cytokinesis, the final stage of cell division, is fundamental to many important biological processes including tissue replenishment, organism development, and wound healing.  Failure of this process has been implicated in the development of genetic disorders and cancers.  During this process, the mother cell progresses through a series of shape changes to produce two genetically equivalent, equally sized daughter cells with similar amounts of cytoplasm.  Different cytoskeletal proteins enrich in the equatorial or global cortices, helping to initiate and drive the shape changes of cytokinesis.  To study this biological process, we designed and built a micropipette aspirator to apply physiologically relevant forces to dividing cells.  Using this instrument, we have discovered a novel mechanosensory mechanism in which equatorial proteins, myosin-II and cortexillin-I, redistribute in response to mechanical load in dividing cells.

This regulatory mechanism helps govern progression through the complex shape changes of cytokinesis.  A computational model of the cell was developed that utilizes linear viscoelastic elements to describe cellular mechanical properties and utilizes level set methods to evolve the boundary of the cell.  Micropipette aspiration was also used to determine experimentally parameters for this model.  This model recapitulates the behavior of interphase cells undergoing micropipette aspiration and will be beneficial for investigating hypotheses concerning the mechanosensory system as well as provide a foundation for simulating other type of cellular processes, such as chemotaxis.

Tuesday, September 4, 2007

3:00 p.m.

Barton Hall 225

FOR DISABILITY INFORMATION

CONTACT:  Candace Abel (410) 516-7031 cabel@jhu.edu