Mutation of a phosphorylatable residue in Put3p affects the magnitude of rapamycin-induced PUT1 activation in a Gat1p-dependent manner.
Saccharomyces cerevisiae can utilize high quality (e.g. glutamine and ammonia) as well as low quality (e.g. gamma-amino butyric acid and proline) nitrogen sources. The transcriptional activator Put3p allows yeast cells to utilize proline as a nitrogen source through expression of the PUT1 and PUT2 genes. Put3p activates high level transcription of these genes by binding proline directly. However, Put3p also responds to other lower quality nitrogen sources. As nitrogen quality decreases, Put3p exhibits an increase in phosphorylation concurrent with an increase in PUT gene expression. The proline-independent activation of the PUT genes requires both Put3p and the positively acting GATA factors, Gln3p and Gat1p. Conversely, the phosphorylation of Put3p is not dependent on GATA factor activity. Here, we find that the mutation of Put3p at amino acid Tyr-788 modulates the proline-independent activation of PUT1 through Gat1p. The phosphorylation of Put3p appears to influence the association of Gat1p, but not Gln3p, to the PUT1 promoter. Combined, our findings suggest that this may represent a mechanism through which yeast cells rapidly adapt to use proline as a nitrogen source under nitrogen limiting conditions.
Leverentz
Michael K
MK
Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.
Campbell
Robert N
RN
Connolly
Yvonne
Y
Whetton
Anthony D
AD
Reece
Richard J
RJ
D000935:Antifungal Agents / Q000494:pharmacology*; D050980:GATA Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects* / Q000235:genetics; D009154:Mutation; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics; D011392:Proline / Q000235:genetics / Q000378:metabolism; D011394:Proline Oxidase / Q000096:biosynthesis* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D020123:Sirolimus / Q000494:pharmacology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics
D000935:Antifungal Agents; C096100:GAT1 protein, S cerevisiae; D050980:GATA Transcription Factors; C071664:GLN3 protein, S cerevisiae; C068399:PUT3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011392:Proline; D011394:Proline Oxidase; D020123:Sirolimus