Linked Life Data

6591195

Source:http://linkedlifedata.com/resource/pubmed/id/6591195

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
1984-10-24
pubmed:abstractText
A eukaryotic initiation factor 2 (eIF-2)-ancillary protein factor Co-eIF-2 promotes displacement of GDP from eIF-2 X GDP and facilitates ternary complex (Met-tRNAf X eIF-2 X GTP) formation in the presence of Mg2+. Heme-regulated protein synthesis inhibitor, HRI, phosphorylates the alpha-subunit of eIF-2 and thus inhibits ternary complex formation as Co-eIF-2 does not displace GDP from eIF-2 alpha (P) X GDP. RF, a high molecular weight cell supernatant factor, reverses protein synthesis inhibition in heme-deficient reticulocyte lysates and also reverses HRI inhibition of ternary complex formation. RF contains Co-eIF-2 activity. In addition, an active RF preparation contains excess alpha-subunit of eIF-2 in the free and unphosphorylated form and this alpha-subunit of eIF-2 is not phosphorylated by HRI and ATP. In this paper we report (i) an active RF preparation contains excess alpha-subunit of eIF-2 and this alpha-subunit can be phosphorylated by HRI and ATP in the presence of GDP; (ii) RF promotes ternary complex formation by eIF-2 X [3H]GDP with accompanying GDP displacement; (iii) in the presence of HRI and ATP, RF promotes ternary complex formation by eIF-2 X [3H]GDP without accompanying GDP displacement; (iv) in the presence of HRI and ATP, the ternary complex formed using RF is active in Met-tRNAf X 40S initiation complex formation; (v) both the ternary complex and the Met-tRNAf X 40S complex formation in the presence of HRI and ATP are completely inhibited by prior incubation of RF with GDP; (vi) upon further fractionation of an active RF fraction, a preparation can be obtained that contains HRI-sensitive Co-eIF-2 activity. However, this preparation does not efficiently reverse protein synthesis inhibition in heme-deficient reticulocyte lysates and does not contain excess alpha-subunit of eIF-2. Based on these observations, we have suggested (a) RF provides the unphosphorylated alpha-subunit to eIF-2 alpha (P) X GDP and restores eIF-2 activity. This RF activity is inhibited as the alpha-subunit in the RF preparation becomes phosphorylated by HRI and ATP in the presence of GDP; (b) RF contains Co-eIF-2 activity, which has dual functions: (i) stimulation of ternary complex formation by eIF-2 and (ii) GDP displacement from eIF-2 X GDP during ternary complex formation. In the presence of HRI and ATP, Co-eIF-2 but does not displace GDP from eIF-2 alpha(P) X GDP.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-236308, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-286294, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-291924, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-293657, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-488111, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6249821, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6553052, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6572381, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6573671, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6826566, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6915935, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6924750, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6941245, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6953412, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-6959132, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-7063012, http://linkedlifedata.com/resource/pubmed/commentcorrection/6591195-974137
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:volume
81
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5379-83
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Protein synthesis in rabbit reticulocytes: a study of the mechanism of action of the protein factor RF that reverses protein synthesis inhibition in heme-deficient reticulocyte lysates.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't