In silico and in vivo analysis reveal a novel gene in Saccharomyces cerevisiae trehalose metabolism.
BACKGROUND
The ability to respond rapidly to fluctuations in environmental changes is decisive for cell survival. Under these conditions trehalose has an essential protective function and its concentration increases in response to enhanced expression of trehalose synthase genes, TPS1, TPS2, TPS3 and TSL1. Intriguingly, the NTH1 gene, which encodes neutral trehalase, is highly expressed at the same time. We have previously shown that trehalase remains in its inactive non-phosphorylated form by the action of an endogenous inhibitor. Recently, a comprehensive two-hybrid analysis revealed a 41-kDa protein encoded by the YLR270w ORF, which interacts with NTH1p.


RESULTS
In this work we investigate the correlation of this Trehalase Associated Protein, in trehalase activity regulation. The neutral trehalase activity in the ylr270w mutant strain was about 4-fold higher than in the control strain. After in vitro activation by PKA the ylr270w mutant total trehalase activity increased 3-fold when compared to a control strain. The expression of the NTH1 gene promoter fused to the heterologous reporter lacZ gene was evaluated. The mutant strain lacking YLR270w exhibited a 2-fold increase in the NTH1-lacZ basal expression when compared to the wild type strain.


CONCLUSIONS
These results strongly indicate a central role for Ylr270p in inhibiting trehalase activity, as well as in the regulation of its expression preventing a wasteful futile cycle of synthesis-degradation of trehalose.
De Mesquita
Joelma F
JF
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av, Professor Lineu Prestes, 748, Bloco 10 terreo, São Paulo, SP, 05508-000, Brazil. jfreire@iq.usp.br
Panek
Anita D
AD
de Araujo
Pedro S
PS
D015870:Gene Expression; D005800:Genes, Fungal; D005964:Glucosyltransferases / Q000235:genetics; D009699:N-Glycosyl Hydrolases / Q000235:genetics / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D017422:Sequence Analysis, DNA; D015533:Transcriptional Activation; D014198:Trehalase / Q000235:genetics / Q000378:metabolism; D014199:Trehalose / Q000378:metabolism*
D029701:Saccharomyces cerevisiae Proteins; D014199:Trehalose; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; D014198:Trehalase; C478395:DCS1 protein, S cerevisiae; D009699:N-Glycosyl Hydrolases