AMINOPROPYLTRANSFERASES

Project: Research project

Description

The overall objectives of the research are: (a) to provide a detailed
understanding of the reactions responsible for the synthesis,
interconversion and removal of polyamines in mammalian cells; (b) to
determine the functions of polyamines; and (c) to use this information
to design and test inhibitors and antagonists of polyamines which have
useful therapeutic properties. The studies will be focussed on three enzymes; spermidine synthase and
spermine synthase, which are aminopropyltransferases respectively
responsible for the synthesis of spermidine and spermine, and
spermidine/spermine- N1-acetyltransferase (SAT) which is a highly
inducible, rate controlling enzyme in the degradation and excretion of
these polyamines. The experiments proposed are: to investigate the
mechanism of SAT induction and evaluate the role of SAT in regulating
polyamine content and efflux; to study the mechanism of polyamine efflux
and the possible role of putrescine in protecting cells against
hypotonic shock; to investigate the function of spermine; and to compare
the structure, specificity and expression of spermidine synthase and
spermine synthase. Specific tools to be used in these studies, which have already been
developed during the work on this project, include antibodies to all
three enzymes, cDNA clones for spermidine synthase and SAT, specific
inhibitors for the aminopropyltransferases, polyamine analogs which have
varying degrees of ability to substitute for the natural polyamines and
to induce SAT, and methods for the analysis of the polyamines and
related nucleosides such as decarboxylated S-adenosylmethionine and
5'-methylthioadenosine. Inhibitors of SAT that can be used to
investigate its function are under development. It is intended to
obtain a cDNA for spermine synthase, genomic clones for these enzymes
and to express the mammalian enzymes in E. coli in order to generate
sufficient protein for the studies. It is also planned to use
appropriate plasmid vectors with inducible promoters to express SAT in
transfected mammalian cells. Polyamines are known to be essential for mammalian cell growth and
polyamine antagonists have been demonstrated to have potential as
antineoplastic agents but these effects are counteracted by the strict
regulation of cellular polyamine levels brought about by compensatory
adjustments of their rate of synthesis, degradation, uptake and
excretion. These studies will identify compounds and protocols to
maximize the effectiveness of antitumor strategies which perturb
cellular polyamine content.
StatusFinished
Effective start/end date4/1/797/31/10

Funding

  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $276,948.00
  • National Institutes of Health: $234,900.00
  • National Institutes of Health
  • National Institutes of Health: $173,744.00
  • National Institutes of Health
  • National Institutes of Health: $276,923.00
  • National Institutes of Health
  • National Institutes of Health: $73,323.00
  • National Institutes of Health
  • National Institutes of Health: $77,288.00
  • National Institutes of Health: $181,960.00
  • National Institutes of Health: $274,050.00
  • National Institutes of Health: $292,137.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $274,050.00
  • National Institutes of Health: $234,900.00
  • National Institutes of Health
  • National Institutes of Health: $206,365.00
  • National Institutes of Health: $285,246.00
  • National Institutes of Health
  • National Institutes of Health

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Spermidine Synthase
Spermine
Polyamines
Spermine Synthase
Acetyltransferases
Enzymes
Acetylesterase
Propylamines