Linked Life Data

15125768

Source:http://linkedlifedata.com/resource/pubmed/id/15125768

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2004-5-5
pubmed:abstractText
In Arabidopsis, the D-type cyclin CYCD3 is rate-limiting for transition of the G(1)/S boundary, and is transcriptionally upregulated at this point in cells re-entering the cell cycle in response to plant hormones and sucrose. However, little is known about the regulation of plant cell-cycle regulators at the protein level. We show here that CYCD3;1 is a phosphoprotein highly regulated at the level of protein abundance, whereas another D-type cyclin CYCD2;1 is not. The level of CYCD3;1 protein falls rapidly on sucrose depletion, correlated with the arrest of cells in G(1) phase, suggesting a rapid turnover of CYCD3;1. Treatment of exponentially growing cells with the protein synthesis inhibitor cycloheximide (CHX) confirms that CYCD3;1 is normally a highly unstable protein, with a half-life of approximately 7 min on CHX treatment. In both sucrose-starved and exponentially growing cells, CYCD3;1 protein abundance increases in response to treatment with MG132 (carbobenzoxyl-leucinyl-leucinyl-leucinal), a reversible proteasome inhibitor, but not in response to the cysteine protease inhibitor E-64 or the calpain inhibitor ALLN (N-acetyl-leucyl-leucyl-norleucinal). The increase on MG132 treatment is because of de novo protein synthesis coupled with the blocking of CYCD3;1 degradation. Longer MG132 treatment leads to C-terminal cleavage of CYCD3;1, accumulation of a hyperphosphorylated form and its subsequent disappearance. We conclude that CYCD3;1 is a highly unstable protein whose proteolysis is mediated by a proteasome-dependent pathway, and whose levels are highly dependent on the rate of CYCD3;1 protein synthesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
616-25
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Differential stability of Arabidopsis D-type cyclins: CYCD3;1 is a highly unstable protein degraded by a proteasome-dependent mechanism.
pubmed:affiliation
Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't