Defense Date

11-6-2003

Graduation Date

Fall 2003

Availability

Immediate Access

Submission Type

thesis

Degree Name

MS

Department

Biological Sciences

Committee Chair

Jana Patton-Vogt

Committee Member

Joseph R. McCormick

Committee Member

Nancy Trun

Committee Member

Ned Young

Keywords

Phospholipid Metabolism

Abstract

Phosphatidylinositol (PI) deacylation in Saccharomyces cerevisiae results in the formation and excretion of glycerophosphoinositol (GPI). This is a predominant route of PI turnover and is not unique to S. cerevisiae. Released GPI can be transported back into the cell through a membrane permease encoded by the GIT1 gene, Git1p. Maximum transport is achieved in low inositol/low phosphate conditions at pHs below 7, and the addition of a protonophore to the GPI transport assay abolishes transport activity. These findings suggest that Git1p is a proton symporter. An excess of unlabeled glycerol-3-phosphate (G3P) inhibits the transport of radiolabeled GPI into S. cerevisiae. Furthermore, radiolabeled G3P is transported into S. cerevisiae in a Git1p-dependent fashion. A GIT1 homolog from Schizosaccharomyces pombe (Sp-git1) was cloned. Overexpression of Sp-git1 did not result in increased transport of GPI into S. cerevisiae or S. pombe cells. However, it resulted in increased transport of inositol in S. pombe.

Format

PDF

Language

English

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