Title

Characterization of mammalian WDR1 during dynamic actin rearrangement events.

Date of Award

2004

Degree Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

First Advisor

Hubberstey, A.

Keywords

Biology, Cell.

Rights

CC BY-NC-ND 4.0

Abstract

The actin cytoskeleton functions within processes such as cell extension, migration, and neurogenesis; yet the mechanisms of actin regulation are not completely understood. WD repeat proteins (WDR1) have recently been shown to interact with actin and regulate cortical actin dynamics through interactions with cofilin in a number of species. However studies on mammalian WDR1 have not been reported. Further studies in chick systems have also indicated several cofilin-independent functions of WDR1 within cytokinesis and cell migration. We investigated the human homologue of yeast WDR1 and identified the expression of two isoforms, a full length 60 kDa protein and an N-terminal truncated 50 kDa protein. Analysis of WDR1 expression in transformed and non-transformed cell lines indicated that the two isoforms were differentially expressed. Sequence analysis revealed the WD motifs were homologous to kelch motifs found within Drosophila kelch. Kelch containing proteins are believed to mediate protein-protein interactions. Protein interaction experiments demonstrated WDR1 bound actin and formed hetero-multimeric complexes; however no interaction with cofilin was observed. Localization studies showed WDR1 localized to actin filaments (similar to vinculin) and to areas undergoing actin rearrangement with cofilin and CAP1. Interestingly, WDR1 was shown to remain attached to glass coverslips as part of a WDR1 aggregated complex (WAC) after trypsin mediated cell detachment. Latrunculin A and cytochalasin D treatments indicated WDR1 may stabilize actin filaments during depolymerizing events. Therefore, these results have provided an initial characterization of the important role of hWDR1 within the critical cellular processes of attachment and migration, and have provided experimental avenues for future pursuit.Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .N66. Source: Masters Abstracts International, Volume: 43-05, page: 1656. Adviser: D. Hubberstey. Thesis (M.Sc.)--University of Windsor (Canada), 2004.