Investigations of Inositol Phosphate-Mediated Transcription

Inositol phosphates (IPs) are eukaryotic signaling molecules that play important roles in a wide range of biological processes. IPs are required for embryonic development and patterning, insulin secretion, the regulation of telomere length, proper progression through the cell cycle, and the regulation of ion channels. This work uses the yeast Saccharomyces cerevisiae as a model system for investigating the functions of IPs and focuses on the transcriptional regulation of the gene encoding the secreted mating pheromone MFα2 by the IP kinase Ipk2 (also called Arg82, ArgR3, and IPMK). This work shows that Ipk2 has both kinase-dependent and kinase-independent functions in regulating the transcription of MFα2. Transcription of MFα2 is also dependent upon the integrity of an Mcm1-binding site in its promoter. This is the first description of a role for this binding site in the transcription of MFα2.

In vivo and in vitro screening approaches to identify additional factors associated with MFα2 expression or with IP biology generally are also described. These unbiased approaches provide some valuable insight for further investigations.