Linked Life Data

1856214

Source:http://linkedlifedata.com/resource/pubmed/id/1856214

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
1991-8-23
pubmed:abstractText
A potential casein kinase II (CK II) recognition site is located within the conserved carboxyl (COOH) terminus of the ribosomal P (phospho) proteins P0, P1, and P2. To determine whether the COOH termini of the P proteins are physiological substrates for CK II, we studied the phosphorylation of the P proteins in vitro and in intact cells. The results show that the addition of exogenous purified CK II and ATP to intact ribosomes in vitro resulted in the relatively selective phosphorylation of all three P proteins. A synthetic peptide corresponding to the COOH-terminal 22 amino acids of P2 (C-22) was also phosphorylated by CK II with a Km of 13.4 microM. An endogenous ribosome-associated, CK II-like enzyme also phosphorylated the P proteins relatively selectively in the presence of 10 mM Mg2+ and ATP. The endogenous kinase was inhibited by heparin, utilized either ATP or GTP as a phosphate donor, and phosphorylated casein. A CK II-specific peptide (Arg-Arg-Arg-Glu-Glu-Glu-Thr-Glu-Glu-Glu) and the C-22 peptide inhibited the phosphorylation of the P proteins by the endogenous kinase, providing further evidence for its CK II-like properties and for localization of the CK II phosphorylation site to the COOH termini of the P proteins. Tryptic phosphopeptide maps of P1 and P2 phosphorylated by exogenous CK II and the endogenous ribosome-bound kinase were virtually identical. These phosphopeptides comigrated with the tryptic digest of C-22 and with the tryptic phosphopeptides derived from P1 and P2 isolated from intact cells metabolically labeled with [32P]orthophosphate in vivo. These studies demonstrate that exogenous CK II and a ribosome-bound, CK II-like enzyme phosphorylate the ribosomal P proteins in vitro and localize the target site for phosphorylation to the COOH terminus. The incorporation of phosphate into the same target site in intact cells indicates that the P proteins are in vivo substrates of CK II.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
266
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13815-20
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Ribosomal proteins P0, P1, and P2 are phosphorylated by casein kinase II at their conserved carboxyl termini.
pubmed:affiliation
Hospital for Special Surgery, Cornell University Medical College, New York, New York 10021.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't