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Product
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MW
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Catalog
Number
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D-ribo-Phytophingosine-1-phosphate
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397.49
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860491
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Stability 1 year
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Storage -20°C
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Our knowledge of sphingolipid metabolism and function in Saccharomyces
cerevisiae is growing rapidly. Dickson & Lester discuss
the current status of sphingolipid metabolism including recent
evidence suggesting that exogenous sphingoid long-chain bases
must first be phosphorylated and then dephosphorylated before
incorporation into ceramide. Phenotypes of strains defective
in sphingolipid metabolism are discussed because they provide
hints about the undiscovered functions of sphingolipids and
are one of the major reasons for studying this model eukaryote.
The long-chain base phosphates, dihydrosphingosine-1-phosphate
and phytosphingosine-1-phosphate, have been hypothesized to
play roles in heat stress resistance, perhaps acting as signaling
molecules. They evaluate the data supporting this hypothesis
and suggest future experiments needed to verify it. Finally,
they discuss recent clues that may help to reveal how sphingolipid
synthesis and total cellular sphingolipid content are regulated.
Sphingolipid long-chain bases and their phosphorylated derivatives,
for example, sphingosine-1-phosphate in mammals, have been implicated
as signaling molecules. The possibility that Saccharomyces cerevisiae
cells also use long-chain-base phosphates to regulate cellular
processes has only recently begun to be examined. Skrzypek,
Nagiec, et al. present a simple and sensitive procedure for
analyzing and quantifying long-chain- base phosphates in S.
cerevisiae cells. These data show for the first time that phytosphingosine-1-phosphate
(PHS-1-P) is present at a low but detectable level in cells
grown on a fermentable carbon source at 25oC, while
dihydrosphingosine-1-phosphate (DHS-1-P) is only barely detectable.
Shifting cells to 37oC causes transient eight- and
fivefold increases in levels of PHS-1-P and DHS-1-P, respectively,
which peak after about 10 min. The amounts of both compounds
return to the unstressed levels by 20min after the temperature
shift. These data are consistent with PHS-1-P and DHS-1-P being
signaling molecules. Cells unable to break down long-chain-base
phosphates, due to deletion of DPL1 and LCB3, show a 500-fold
increase in PHS-1-P and DHS-1-P levels, grow slowly, and survive
a 44oC heat stress 10-fold better than parental cells.
These and other data for dpl1 or lcb3 single-mutant strains
suggest that DHS-1-P and/or PHS-1-P act as signals for resistance
to heat stress. Their procedure should expedite experiments
to determine how the synthesis and breakdown of these compounds
is regulated and how the compounds mediate resistance to elevated
temperature.
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References:
- Dickson, R.C. and R.L.
Lester. (1999) Metabolism and selected functions of sphingolipids
in the yeast Saccharomyces cerevisiae. Biochim Biophys
Acta 1438:305-21.
- Skrzypek, M.S., M.M. Nagiec, R.L. Lester,
and R.C. Dickson.(1999) Analysis of phosphorylated sphingolipid
long-chain bases reveals potential roles in heat stress
and growth control in Saccharomyces. J Bacteriol 181:1134-40.
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