Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2006-12-12
pubmed:abstractText
The Met4 transcriptional activator of methionine biosynthesis is negatively regulated by the SCFMet30 ubiquitin ligase in response to accumulation of methionine. This mechanism requires polyubiquitination, but not proteolysis. We report that a previously unappreciated mechanism involving growth control regulates Met4. Unless methionine is present in the growth medium, polyubiquitinated Met4 is stabilized in late exponential cultures, correlating with transcriptional repression. Polyubiquitinated Met4 becomes destabilized in a proteasome-dependent manner upon reentry into exponential growth, correlating with transcriptional activation. Met4 stabilization is regulated at the level of SCFMet30 binding and requires transcriptional cofactors. These lock Met4 and SCFMet30 into a tight complex active in ubiquitination but incapable of binding the proteasome. Release of polyubiquitinated Met4 from SCFMet30 is sufficient for degradation, and specific sulfur amino acids can promote the degradation by destabilizing Met4 binding to cofactors and SCFMet30. Thus, destabilization of cofactors and SCFMet30 binding is the rate-limiting regulatory step in Met4 proteolysis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Basic-Leucine Zipper Transcription..., http://linkedlifedata.com/resource/pubmed/chemical/Coenzymes, http://linkedlifedata.com/resource/pubmed/chemical/Cysteine, http://linkedlifedata.com/resource/pubmed/chemical/F-Box Proteins, http://linkedlifedata.com/resource/pubmed/chemical/MET30 protein, S cerevisiae, http://linkedlifedata.com/resource/pubmed/chemical/MET4 protein, S cerevisiae, http://linkedlifedata.com/resource/pubmed/chemical/Methionine, http://linkedlifedata.com/resource/pubmed/chemical/Polyubiquitin, http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Repressor Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Saccharomyces cerevisiae Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Ubiquitin-Protein Ligase Complexes
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1097-2765
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
689-99
pubmed:dateRevised
2009-6-2
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Destabilization of binding to cofactors and SCFMet30 is the rate-limiting regulatory step in degradation of polyubiquitinated Met4.
pubmed:affiliation
Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural