Inositol phosphates and the enzymes that interconvert them are key regulators of diverse cellular processes including the transcriptional machinery of arginine synthesis [York, J. D. (2006) Regulation of nuclear processes by inositol polyphosphates. Biochim.Biophys.Acta 1761, 552-559]. Despite considerable interest and debate surrounding the role of Saccharomyces cerevisiae inositol polyphosphate kinase (ScIPK2, ARG82, ARGRIII) and its inositol polyphosphate products in these processes, there is an absence of data describing how the transcripts of the arginine synthetic pathway, and the amino acid content of ScIpk2Delta, are altered under different nutrient regimes. We have cloned an inositol phosphate multikinase from Solanum tuberosum, StIPMK (Genbank accession, EF362785), that despite considerable sequence divergence from ScIPK2, restores the arginine biosynthesis pathway transcripts ARG8, acetylornithine aminotransferase, and ARG3, ornithine carbamoyltransferase of ScIpk2Delta yeast to Wild Type profiles. StIPMK also restores the amino acid profiles of mutant yeast to Wild Type, and does so with ornithine or arginine as sole nitrogen sources. Our data reveal a lysine accumulation phenotype in ScIpk2Delta yeast that is restored to Wild Type profile by expression of StIPMK, including restoration of the transcript profiles of lysine biosynthetic genes. That StIPMK shows only 18.6% identity with ScIPK2 likely indicates that the rescue of transcript and diverse amino acid phenotypes is not mediated through direct interaction of StIPMK with the ArgR-Mcm1 transcription factor complex that is a molecular partner of ScIPK2.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|