+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Protein synthesis in rabbit reticulocytes: characteristics of the protein factor RF that reverses inhibition of protein synthesis in heme-deficient reticulocyte lysates



Protein synthesis in rabbit reticulocytes: characteristics of the protein factor RF that reverses inhibition of protein synthesis in heme-deficient reticulocyte lysates



Proceedings of the National Academy of Sciences of the United States of America 79(21): 6517-6521



During heme deficiency in reticulocyte lysates, the heme-regulated translational inhibitor of protein synthesis (HRI) is activated and shuts off protein synthesis. In partial reactions, HRI phosphorylates the Mr 38,000 subunit (alpha subunit) of eukaryotic initiation factor 2 (eIF-2), which forms a ternary complex, Met-tRNAf X eIF-2 X GTP. The eIF-2 alpha (P) thus formed is not recognized by two eIF-2 ancillary factors, Co-eIF-2B (which promotes the dissociation of the ternary complex at high Mg2+) and Co-eIF-2C (which reverses the inhibition of ternary complex formation), and thus, is presumably inactive in peptide chain initiation. A protein factor, designated RF, which reverses inhibition of protein synthesis in heme-deficient reticulocyte lysates, has been purified from reticulocyte cell supernatant. RF is a high molecular weight (Mr approximately equal to 450,000) protein complex composed of multiple polypeptides. An active RF preparation contains Co-eIF-2B and Co-eIF-2C activities, and these two activities in RF preparation are not inhibited by HRI and ATP--i.e., eIF-2 alpha (P) is recognized. During purification, RF remains associated with eIF-2 activity (eIF-2 X RF) and can be freed of this eIF-2 activity by CM-Sephadex chromatography. Both eIF-2 X RF and RF contain a Mr 38,000 polypeptide component that is indistinguishable from the Mr 38,000 subunit of eIF-2 by two-dimensional gel electrophoresis. It has been observed that a significant part of this Mr 38,000 polypeptide component in eIF-2 X RF and almost the entire Mr 38,000 polypeptide component in RF remain unphosphorylated after prolonged incubation with HRI and ATP. A possible role of this free Mr 38,000 polypeptide in RF action is discussed.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 044078100

Download citation: RISBibTeXText

PMID: 6959132

DOI: 10.2307/13257


Related references

Protein synthesis in rabbit reticulocytes further studies of the characteristics of the protein factor that reverses the inhibition of protein synthesis in heme deficient reticulocyte lysates. Federation Proceedings 40(6): 1549, 1981

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. Proceedings of the National Academy of Sciences of the United States of America 81(17): 5379-5383, 1984

Protein synthesis in rabbit reticulocytes: characteristics of a ribosomal factor that reverses inhibition of protein synthesis in heme-deficient lysates. Proceedings of the National Academy of Sciences of the United States of America 75(10): 4858-4862, 1978

Protein synthesis in rabbit reticulocytes: characteristics of a postribosomal supernatant factor that reverses inhibition of protein synthesis in heme-deficient lysates and inhibition of ternary complex (Met-tRNAfMet.eIF-2.GTP) formation by heme-regulated inhibitor. Proceedings of the National Academy of Sciences of the United States of America 76(11): 5490-5494, 1979

Regulation of protein synthesis in rabbit reticulocyte lysates: characteristics of inhibition of protein synthesis by a translational inhibitor from heme-deficient lysates and its relationship to the initiation factor which binds Met-tRNAf. Proceedings of the National Academy of Sciences of the United States of America 73(8): 2720-2724, 1976

Purification and characterization of a protein factor that reverses the inhibition of protein synthesis by the heme-regulated translational inhibitor in rabbit reticulocyte lysates. European Journal of Biochemistry 98(2): 513-520, 1979

Isolation of a protein factor involved in the regulation of protein synthesis in heme deficient rabbit reticulocyte lysates. Federation Proceedings 36(3): 868, 1977

Regulation of protein synthesis in rabbit reticulocyte lysates: preparation of efficient protein synthesis lysates and the purification and characterization of the heme-regulated translational inhibitory protein kinase. Methods in Enzymology 60: 459-484, 1979

Gtp rescues protein synthesis in heme deficient reticulocyte lysates by the inhibition of heme regulation eukaryotic initiation factor eif 2 alpha kinase activity. Federation Proceedings 44(4): 1222, 1985

Control of protein synthesis in rabbit reticulocyte lysates effects of cyclic amp atp and gtp on the inhibitions of protein synthesis induced by heme deficiency double stranded rna and a reticulocyte translational inhibitor. Federation Proceedings 35(7): 803, 1976

Regulation of protein synthesis in rabbit reticulocyte lysates by the heme-regulated protein kinase: inhibition of interaction of Met-tRNAfMet binding factor with another initiation factor in formation of Met-tRNAfMet.40S ribosomal subunit complexes. Proceedings of the National Academy of Sciences of the United States of America 75(2): 745-749, 1978

Regulation of protein synthesis in rabbit reticulocyte lysates. Thiophosphorylation of initiation factor eIF-2 by heme-regulated protein kinase. Febs Letters 208(1): 117-122, 1986

Protein synthesis in rabbit reticulocytes. Purification and characterization of a double-stranded RNA-dependent protein synthesis inhibitor from reticulocyte lysates. Journal of Biological Chemistry 256(12): 6491-6495, 1981

Regulation of protein synthesis in rabbit reticulocyte lysates. Requirement of initiation factor eIF-2 holoprotein for substrate specificity of heme-regulated protein kinase. Febs Letters 209(2): 162-164, 1986

Regulation of protein synthesis in rabbit reticulocyte lysates the heme regulated protein kinase and double stranded rna induced protein kinase phosphorylate the same sites on initiation factor eif 2. Biochemical & Biophysical Research Communications 91(4): 1437-1444, 1979