Linked Life Data

16365046

Source:http://linkedlifedata.com/resource/pubmed/id/16365046

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2006-2-13
pubmed:abstractText
Saccharomyces cerevisiae Rad53, the ortholog of mammalian Chk2, is an essential protein kinase in DNA damage and DNA replication checkpoint pathways. Consecutive phosphatidyl inositol kinase-like kinase (PIKK)-dependent and PIKK-independent steps in activation of Rad53 are key steps for controlling and transmitting diverse downstream responses to DNA damage. However, these activities have not been demonstrated in vitro in defined systems. Here, we have shown that enzymatically dephosphorylated purified Rad53 autoactivates in vitro through a phosphorylation-dependent mechanism. Kinetic analysis demonstrated that autophosphorylation results in a more than 9-fold increase in protein kinase activity. Autophosphorylation was Rad53 concentration-dependent, indicating that the reaction follows an intermolecular mechanism. DNA damage induced oligomerization of a subset of Rad53 molecules in vivo. At low concentrations of Rad53, preincubation of Rad53 with immune complexes containing the Mec1/Ddc2 complex can activate Rad53 kinase activity. Our findings showed that Mec1/Ddc2 complexes can directly activate Rad53 through a phosphorylation-dependent mechanism, and more generally, supported the hypothesis that PIKKs regulate Chk2 orthologs through phosphorylation. Moreover, this work has substantiated a model for PIKK-independent amplification of Rad53 activation (and by extension, activation of other Chk2 orthologs) mediated by inter-Rad53 phosphorylation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3954-63
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Activation of the checkpoint kinase Rad53 by the phosphatidyl inositol kinase-like kinase Mec1.
pubmed:affiliation
Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural