PHOSPHOLIPID METABOLISM AND MEMBRANE FUNCTION

Project Details

Description

In the yeast Saccharomyces cerevisiae, phosphatidate (PA)
phosphatase plays an important role in the regulation of
phospholipid biosynthesis by the primary (phosphatidylethanolamine
methylation) and auxiliary (CDP-ethanolamine- and CDP--
choline-based) pathways. The enzyme also plays a role in the
overall regulation controlling the proportional synthesis of
phosholipids and triacylglycerols. In the past grant period we
purified and characterized 45-kDa and 104-kDa forms of PA
phosphatase. Our studies indicated that the expression of the two
forms of PA phosphatase were regulated differentially by inositol
and the enzyme activities were regulated differentially by
phosphorylation. In this competitive renewal application we
propose studies that are expected to provide insight into the
regulation of PA phosphatase activity as well as the expression of
the enzyme. The phosphorylation of PA phosphatase by
cAMP-dependent protein kinase and the effects of phosphorylation
on enzyme activity and kinetics will be examined using pure enzyme.
The phosphorylation of PA phosphatase in vivo will be examined in
wild-type and mutant cells defective in cAMP-dependent protein
kinase activity. The effects of PA phosphatase phosphorylation on
overall lipid biosynthesis will be examined. Systematic kinetic
studies are proposed to examine the effect of lipid activators and
inhibitors on the activity of pure PA phosphatase. Kinetic
experiments will be performed using well-defined Triton
X-100/phospholipid mixed micelles as an experimental system. The
mixed micelle studies will be complemented with studies using pure
enzymes reconstituted into unilamellar phospholipid vesicles. We
will initiate a project to clone the structural genes for the
45-kDa and 104-kDa forms of PA phosphatase. We will use specific
antibodies to the enzymes and lambda-gtll genomic expression and
lambda-ZAP cDNA expression libraries. The cloned genes will be
used as probes to study the regulation of the mRNA levels of the
45-kDa and 104-kDa forms of PA phosphatase in response to inositol
and during the growth phase. The essential nature of PA
phosphatase will also be addressed. The results of the proposed
studies with S. cerevisiae should be relevant to higher eukaryotic
organisms.
StatusFinished
Effective start/end date7/1/806/30/20

Funding

  • National Institutes of Health: $351,897.00
  • National Institutes of Health: $402,039.00
  • National Institutes of Health: $362,240.00
  • National Institutes of Health: $272,956.00
  • National Institutes of Health: $354,435.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $367,290.00
  • National Institutes of Health: $352,771.00
  • National Institutes of Health: $365,112.00
  • National Institutes of Health
  • National Institutes of Health: $459,278.00
  • National Institutes of Health: $368,800.00
  • National Institutes of Health: $367,290.00
  • National Institutes of Health: $402,039.00
  • National Institutes of Health: $135,524.00
  • National Institutes of Health: $18,079.00
  • National Institutes of Health: $352,771.00
  • National Institutes of Health: $255,106.00
  • National Institutes of Health
  • National Institutes of Health: $249,015.00
  • National Institutes of Health: $181,118.00
  • National Institutes of Health: $289,633.00
  • National Institutes of Health: $76,500.00
  • National Institutes of Health: $289,633.00
  • National Institutes of Health: $70,900.00
  • National Institutes of Health
  • National Institutes of Health: $402,039.00
  • National Institutes of Health: $402,039.00
  • National Institutes of Health: $325,792.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $93,071.00
  • National Institutes of Health
  • National Institutes of Health: $289,633.00
  • National Institutes of Health
  • National Institutes of Health

ASJC

  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)

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