Linked Life Data

3848434

Source:http://linkedlifedata.com/resource/pubmed/id/3848434

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
1985-8-29
pubmed:abstractText
The phosphorylation of eukaryotic initiation factor (eIF) 2 alpha that occurs when rabbit reticulocyte lysate is incubated in the absence of hemin or with poly(I.C) causes inhibition of polypeptide chain initiation by preventing a separate factor (termed RF) from promoting the exchange of GTP for GDP on eIF-2. When lysate was incubated in the presence of hemin and [14C] eIF-2 or [alpha-32P]GTP, we observed binding of eIF-2 and GDP or GTP to 60 S ribosomal subunits that was slightly greater than that bound to 40 S subunits and little binding to 80 S ribosomes. When incubation was in the absence of hemin or in the presence of hemin plus 0.1 microgram/ml poly(I.C), eIF-2 and GDP binding to 60 S subunits was increased 1.5- to 2-fold, that bound to 80 S ribosomes was almost as great as that bound to 60 S subunits, and that bound to 40 S subunits was unchanged. Our data indicate that about 40% of the eIF-2 that becomes bound to 60 S subunits and 80 S ribosomes in the absence of hemin or with poly(I.C) is eIF-2(alpha-P) and suggest that the eIF-2 and GDP bound is probably in the form of a binary complex. The accumulation of eIF-2.GDP on 60 S subunits occurs before binding of Met-tRNAf to 40 S subunits becomes reduced and before protein synthesis becomes inhibited. The rate of turnover of GDP (presumably eIF-2.GDP) on 60 S subunits and 80 S ribosomes in the absence of hemin is reduced to less than 10% the control rate, because the dissociation of eIF-2.GDP is inhibited. Additional RF increases the turnover of eIF-2.GDP on 60 S subunits and 80 S ribosomes to near the control rate by promoting dissociation of eIF-2.GDP but not eIF-2(alpha-P).GDP. Our findings suggest that eIF-2.GTP binding to and eIF-2.GDP release from 60 S subunits may normally occur and serve to promote subunit joining. The phosphorylation of eIF-2 alpha inhibits polypeptide chain initiation by preventing dissociation of eIF-2.GDP from either free 60 S subunits (thus inhibiting subunit joining directly) or the 60 S subunit component of an 80 S initiation complex (thereby blocking elongation and resulting in the dissociation of the 80 S complex).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Blood Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Carbon Radioisotopes, http://linkedlifedata.com/resource/pubmed/chemical/Eukaryotic Initiation Factor-2, http://linkedlifedata.com/resource/pubmed/chemical/Guanine Nucleotides, http://linkedlifedata.com/resource/pubmed/chemical/Guanosine Diphosphate, http://linkedlifedata.com/resource/pubmed/chemical/Guanosine Triphosphate, http://linkedlifedata.com/resource/pubmed/chemical/Peptide Initiation Factors, http://linkedlifedata.com/resource/pubmed/chemical/Phosphorus Radioisotopes, http://linkedlifedata.com/resource/pubmed/chemical/Proteins, http://linkedlifedata.com/resource/pubmed/chemical/RNA, Transfer, Amino Acyl, http://linkedlifedata.com/resource/pubmed/chemical/tRNA(m)(Met), methionine-
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
260
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9491-500
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Evidence that the primary effect of phosphorylation of eukaryotic initiation factor 2(alpha) in rabbit reticulocyte lysate is inhibition of the release of eukaryotic initiation factor-2.GDP from 60 S ribosomal subunits.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.