Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
2007-6-18
pubmed:abstractText
Transglutaminase 2 (TG2, tissue transglutaminase) is a multifunctional protein involved in cross-linking a variety of proteins, including retinoblastoma protein (Rb). Here we show that Rb is also a substrate for the recently identified serine/threonine kinase activity of TG2 and that TG2 phosphorylates Rb at the critically important Ser780 residue. Furthermore, phosphorylation of Rb by TG2 destabilizes the Rb.E2F1 complex. TG2 phosphorylation of Rb was abrogated by high Ca2+ concentrations, whereas TG2 transamidating activity was inhibited by ATP. TG2 was itself phosphorylated by protein kinase A (PKA). Phosphorylation of TG2 by PKA attenuated its transamidating activity and enhanced its kinase activity. Activation of PKA in mouse embryonic fibroblasts (MEF) with dibutyryl-cAMP enhanced phosphorylation of both TG2 and Rb by a process that was inhibited by the PKA inhibitor H89. Treatment with dibutyryl-cAMP enhanced Rb phosphorylation in MEFtg2+/+ cells but not in MEFtg2-/- cells. These data indicate that Rb is a substrate for TG2 kinase activity and suggest that phosphorylation of Rb, which results from activation of PKA in fibroblasts, is indirect and requires TG2 kinase activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
18108-15
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Transglutaminase 2 kinase activity facilitates protein kinase A-induced phosphorylation of retinoblastoma protein.
pubmed:affiliation
Department of Physiology, University of Manitoba, Winnipeg R3E 0W3, Canada, and the Biochemistry Laboratory, Instituto Dermapatico dell'Immaculata-Institute for Hospitalization, Care and Scientific Research, Tor Vergata, Italy. mishra@cc.umanitoba.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't