Molecular mechanisms of control of protein biosynthesis
- PMID: 7035174
Molecular mechanisms of control of protein biosynthesis
Abstract
Reticulocytes contain two protein kinases which, when activated, phosphorylate the alpha subunit of the chain initiation factor eIF-2 interfering with its function. One kinase is activated in the absence of heme, the other is activated by low concentrations of double-stranded RNA. Both appear to be active in a phosphorylated form. Phosphorylation of the eIF-2 alpha subunit does not modify the basic properties of the factor but prevents its interaction with a stimulating protein (SP) required for binary complex formation at low, physiological concentrations of eIF-2 and Mg 2+. SP, isolated in the form of an eIF-2 complex (eIF-2. SP) of high molecular weight (approximately 450000), promotes formation of a GTP . eIF-2 binary complex, the first step of initiation, in a catalytic fashion. The available evidence suggests that eIF-2 . SP can form in the presence of Mg 2+ a GTP . eIF-2 . SP complex that interacts with free eIF-2 forming GTP . eIF-2 (binary complex) and eIF-2. SP.
Similar articles
-
Regulation of protein synthesis.Eur J Cell Biol. 1979 Jun;19(2):95-101. Eur J Cell Biol. 1979. PMID: 223849 Review.
-
Mode of action of the heme-controlled translational inhibitor: relationship of eukaryotic initiation factor 2-stimulating protein to translation restoring factor.Proc Natl Acad Sci U S A. 1981 Jan;78(1):220-3. doi: 10.1073/pnas.78.1.220. Proc Natl Acad Sci U S A. 1981. PMID: 6941245 Free PMC article.
-
Mechanism of polypeptide chain initiation in eukaryotes and its control by phosphorylation of the alpha subunit of initiation factor 2.Proc Natl Acad Sci U S A. 1982 Apr;79(8):2537-40. doi: 10.1073/pnas.79.8.2537. Proc Natl Acad Sci U S A. 1982. PMID: 6953412 Free PMC article.
-
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.Proc Natl Acad Sci U S A. 1984 Sep;81(17):5379-83. doi: 10.1073/pnas.81.17.5379. Proc Natl Acad Sci U S A. 1984. PMID: 6591195 Free PMC article.
-
Regulation of protein synthesis in eukaryotic cells by the guanine nucleotide exchange factor and chain initiation factor 2.SAAS Bull Biochem Biotechnol. 1996;9:1-8. SAAS Bull Biochem Biotechnol. 1996. PMID: 8652127 Review.