(R2084) The Spo7 EFW Sequence is Required for Nem1-Spo7 Phosphatase Function in Yeast Lipid Metabolism

Ruta Jog (Rutgers University)| Prabuddha Dey (Rutgers University)| Mona Mirheydari (Rutgers University)| Gil-Soo Han (Rutgers University)| George Carman (Rutgers University)

In the yeast Saccharomyces cerevisiae, the Nem1-Spo7 phosphatase complex catalyzes the dephosphorylation of Pah1 phosphatidate phosphatase, controlling its localization to the nuclear/endoplasmic reticulum membrane for the production of diacylglycerol used for triacylglycerol synthesis.  Spo7 in the protein phosphatase complex is a regulatory subunit required for the function of the catalytic subunit Nem1.  To better understand the role of Spo7, we examined its sequence involved in the phosphatase complex formation or interaction with the substrate Pah1. By deletion analyses and site-directed mutagenesis, we found that the C-terminal sequence of Spo7 (EFW, residues 238-240) is important for the phosphatase complex as indicated by the loss-of-function phenotypes (e.g., temperature sensitivity, defect in triacylglycerol synthesis).  We are currently investigating whether the Spo7 EFW sequence is required for physical interaction with Nem1 or Pah1.