Uncovering the signal transduction pathway that regulates the proliferation of Dictyostelium cells
Gomer, Richard H.
Master of Arts
AprA (Autocrine Proliferation Repressor) is a secreted factor that represses proliferation in the slime mold Diclyostelium discoideum . Although the role AprA plays in the regulation of proliferation is known, the signaling pathway by which it occurs is yet to be determined. To discover the different components of the AprA signaling pathway, I examined 12 REMI mutants which proliferated in a similar manner to aprA - cells. Three of 12 mutants were insensitive to AprA. MetPOE was one of the mutants that were insensitive to AprA, and I attempted to construct a complete knockout of the disrupted gene. From an additional REMI screen that I conducted, I found that disruption of dokA led to a mutant with a phenotype similar to aprA-, suggesting this protein may also have a role in the AprA signal transduction pathway. Preliminary data suggested that G proteins may also play a role in the AprA signal transduction pathway. I further characterized six G protein null mutants. I determined that both galpha8- and gbeta- cells were multinucleate. Also there was an increase in the percentage of cells in S phase in gbeta - cells. The similarities between aprA- cells and ga8- and gbeta - cells suggested that Galpha8- and Gbeta - may be part of the AprA signal transduction pathway.
Cellular biology; Chemistry; Biochemistry