THE ROLE OF CYTOSKELETON PROTEINS IN THE DETERMINATION OF NEURONAL POLARITY

Open Access
Author:
Han, Anna Q.
Area of Honors:
Bioengineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Dr Gong Chen, Thesis Supervisor
  • William O Hancock, Honors Advisor
  • Peter J Butler, Faculty Reader
Keywords:
  • cytoskeleton proteins
  • cofilin
  • slingshot
  • LIM kinase
  • neuronal polarity
  • hippocampal neurons
Abstract:
The Par protein family and the LIM kinase slingshot cofilin complex of proteins are implicated in regulating neuronal development and differentiation, the study of which holds promise for applications of neurological disease pathologies and therapies. This research project focuses on proteins that affect the components of the neuronal cytoskeleton, primarily actin and tubulin, which form the cell’s actin filaments and microtubules, respectively. The main proteins of interest were the LIM kinase slingshot cofilin complex. Downstream of well-established polarity proteins Par 3 and Par 6, this complex impacts neurite differentiation through the stabilization or destabilization of actin and tubulin. By transfecting young neurons with an excess of a particular wild type protein or with a knockdown plasmid of a particular protein, it was determined that cofilin wild type and LIM kinase wild type caused little change in polarity development while cofilin knockdown and slingshot wild type caused moderate changes and LIM kinase knockdown dramatically reduced the normal polarity phenotype. Rescue mechanisms were also studied. By co transfecting proteins known to affect normal polarity expression with an excess of actin and tubulin, it was found that polarity defects were able to be rescued. Future research avenues include studying the molecular mechanisms of and identifying alternative proteins for polarity rescue.