Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences

First Advisor

Cotter, D.


Biology, Molecular.




The regulation of cellular actin is critical in numerous dynamic processes in cells including cytokinesis, cytoplasmic streaming, and vesicle trafficking. In the slime mold Dictyostelium discoideum, a 43 kDa tyrosine phosphorylated protein, in dormant spores, has been shown to be actin. In this investigation similar patterns also have been found in Dictyostelium purpureum and Dictyostelium mucoroides. The use of heat activation temperatures also were used to determine if these exposures caused actin dephosphorylation directly or indirectly by stimulating germination. Treatments following spore activation that block germination, such as dinitrophenol, azide, anaerobic conditions, osmotic pressure, or phosphatase inhibitors, maintain tyrosine phosphorylation of actin which is detectable by Western blot analysis. A second aspect of this study employs the use of the protein synthesis inhibitor, cycloheximide, to investigate the stage specific patterns of actin tyrosine phosphorylation in dormant, swollen, and germinating spores. Another aspect of this work employed trifluoperazine (TFP), an inhibitor of calmodulin function. Stages of the sexual life cycle of D. mucoroides were sampled and analyzed for the presence of actin tyrosine phosphorylation. The final aspect of this study investigated the actin tyrosine phosphorylation patterns of several mutants including RasG, which have been implicated in cytoskeleton mobilization. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1998 .C54. Source: Masters Abstracts International, Volume: 39-02, page: 0451. Adviser: David A. Cotter. Thesis (M.Sc.)--University of Windsor (Canada), 1998.