Linked Life Data

7992505

Source:http://linkedlifedata.com/resource/pubmed/id/7992505

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1995-1-11
pubmed:abstractText
Addition of a nitrogen-source to glucose-repressed, nitrogen-starved G0 cells of the yeast Saccharomyces cerevisiae in the presence of a fermentable carbon source induces growth and causes within a few minutes a five-fold, protein-synthesis-independent increase in the activity of trehalase. Nitrogen-activated trehalase could be deactivated in vitro by alkaline phosphatase treatment, supporting the idea that the activation is triggered by phosphorylation. Yeast strains containing only one of the three TPK genes (which encode the catalytic subunit of cAMP-dependent protein kinase) showed different degrees of nitrogen-induced trehalase activation. The order of effectiveness was different from that previously reported for glucose-induced activation of trehalase in glucose-depressed yeast cells. Further reduction of TPK-encoded catalytic subunit activity by partially inactivating point mutations in the remaining TPK gene further diminished nitrogen-induced trehalase activation, while deletion of the BCY1 gene (which encodes the regulatory subunit) in the same strains resulted in an increase in the extent of activation. Deletion of the RAS genes in such a tpkw1 bcy1 strain had no effect. These results are consistent with mediation of nitrogen-induced trehalase activation by the free catalytic subunits alone. They support our previous conclusion that cAMP does not act as second messenger in this nitrogen-induced activation process and our suggestion that a novel nitrogen-induced signaling pathway integrates with the cAMP pathway at the level of the free catalytic subunits of protein kinase A. Western blot experiments showed that the differences in the extent of trehalase activation were not due to differences in trehalase expression. On the other hand, we cannot completely exclude that protein kinase A influences the nitrogen-induced activation mechanism itself rather than acting directly on trehalase. However, any such alternative explanation requires the existence of an additional, yet unknown, mechanism for activation of trehalase besides the well-established regulation by protein kinase A.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0749-503X
pubmed:author
pubmed:issnType
Print
pubmed:volume
10
pubmed:geneSymbol
TPK1, TPK2, TPK3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1049-64
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Activation of trehalase during growth induction by nitrogen sources in the yeast Saccharomyces cerevisiae depends on the free catalytic subunits of cAMP-dependent protein kinase, but not on functional Ras proteins.
pubmed:affiliation
Laboratorium voor Moleculaire Celbiologie, Katholieke Universiteit te Leuven, Flanders, Belgium.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't