Control of dinucleoside polyphosphates by the FHIT-homologous HNT2 gene, adenine biosynthesis and heat shock in Saccharomyces cerevisiae
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1471-2199-3-7.pdf
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Author(s)
Rubio-Texeira, Marta
Varnum, James M
Bieganowski, Pawel
Brenner, Charles
Date Issued
May 2002
Journal
BMC Molecular Biology
Publisher
BioMed Central Ltd
Citation
BMC Molecular Biology. 2002 May 20;3(1):7
Version
Final published version
Abstract
Background: The FHIT gene is lost early in the development of many tumors. Fhit possesses intrinsic ApppA hydrolase activity though ApppA cleavage is not required for tumor suppression. Because a mutant form of Fhit that is functional in tumor suppression and defective in catalysis binds ApppA well, it was hypothesized that Fhit-substrate complexes are the active, signaling form of Fhit. Which substrates are most important for Fhit signaling remain unknown. Results: Here we demonstrate that dinucleoside polyphosphate levels increase 500-fold to hundreds of micromolar in strains devoid of the Saccharomyces cerevisiae homolog of Fhit, Hnt2. Accumulation of dinucleoside polyphosphates is reversed by re-expression of Hnt2 and is active site-dependent. Dinucleoside polyphosphate levels depend on an intact adenine biosynthetic pathway and time in liquid culture, and are induced by heat shock to greater than 0.1 millimolar even in Hnt2+ cells. Conclusions: The data indicate that Hnt2 hydrolyzes both ApppN and AppppN in vivo and that, in heat-shocked, adenine prototrophic yeast strains, dinucleoside polyphosphates accumulate to levels in which they may saturate Hnt2.
MIT Department
Massachusetts Institute of Technology. Department of Biology
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DOI of Published Version
https://doi.org/10.1186/1471-2199-3-7
