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BONANOU-TZEDAKI SA, SOHI MK, ARNSTEIN HRV. Regulation of Protein Synthesis in Reticulocyte Lysates. ACTA ACUST UNITED AC 2005. [DOI: 10.1111/j.1432-1033.1981.tb06174.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gross M, Kaplansky DA, Knish WM. Equilibration of methionine into the Met-tRNA pool of rabbit reticulocyte lysates. FEBS Lett 2001; 160:249-54. [PMID: 6554203 DOI: 10.1016/0014-5793(83)80976-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have measured the rate of equilibration of [35S]methionine into the Met-tRNA pool of rabbit reticulocyte lysate as in [FEBS Lett. (1982) 143, 301-305]. Our results indicate that hemin-deficiency inhibits the equilibration of methionine into the tRNA pool much less than protein synthesis or the equilibration of alanine into the tRNA pool, whereas cycloheximide inhibits these processes similarly. This finding is consistent with our previous data and supports the hypothesis that with hemin-deficiency much of the Met-tRNAf that becomes bound to 40 S subunits subsequently undergoes enzymatic deacylation.
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Inhibition of Protein Synthesis by Nitric Oxide Correlates with Cytostatic Activity: Nitric Oxide Induces Phosphorylation of Initiation Factor eIF-2α. Mol Med 1998. [DOI: 10.1007/bf03401915] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Kim YM, Son K, Hong SJ, Green A, Chen JJ, Tzeng E, Hierholzer C, Billiar TR. Inhibition of protein synthesis by nitric oxide correlates with cytostatic activity: nitric oxide induces phosphorylation of initiation factor eIF-2 alpha. Mol Med 1998; 4:179-90. [PMID: 9562976 PMCID: PMC2230356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Nitric oxide (NO) is cytostatic for proliferating cells, inhibits microbial growth, and down-regulates the synthesis of specific proteins. Studies were undertaken to determine the mechanism by which NO inhibits total protein synthesis and whether the inhibition correlates with established cytostatic activities of NO. MATERIALS AND METHODS In in vitro experiments, various cell types were exposed to NO using either donors or expression of inducible NO synthase (iNOS). The capacity of NO to suppress total protein synthesis, measured by incorporation of 35S-methionine into protein, was correlated with the capacity of NO to suppress cell proliferation, viral replication, or iNOS expression. Phosphorylation of eIF-2 alpha was examined as a possible mechanism for the suppressed protein synthesis by NO. RESULTS Both NO donors and expression of the iNOS suppressed total protein synthesis in L929 cells and A2008 human ovarian tumor cells in parallel with decreased cell proliferation. Suppressed protein synthesis was also shown to correlate with decreased vaccinia virus proliferation in murine peritoneal macrophages in an iNOS-dependent manner. Furthermore, iNOS expression in pancreatic islets or RAW264.7 cells almost completely inhibited total protein synthesis, suggesting that nonspecific inhibition of protein synthesis may be the mechanism by which NO inhibited the synthesis of specific proteins such as insulin or iNOS itself. This possibility was confirmed in RAW264.7 cells where the inhibition of total protein synthesis correlated with the decreased iNOS protein. The decrease in protein levels occurred without changes in iNOS mRNA levels, implicating an inhibition of translation. Mechanistic studies revealed that iNOS expression in RAW264.7 cells resulted in the phosphorylation of eIF-2 alpha and inhibition of the 80S ribosomal complex formation. CONCLUSIONS These results suggest that NO suppresses protein synthesis by stimulating the phosphorylation of eIF-2 alpha. Furthermore, our observations indicate that nonspecific inhibition of protein synthesis may be a generalized response of cells exposed to high levels of NO and that inhibition of protein synthesis may contribute to many of the described cytostatic actions of NO.
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Affiliation(s)
- Y M Kim
- Department of Surgery, University of Pittsburgh, Pennsylvania, USA
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Association of HSP90 with the heme-regulated eukaryotic initiation factor 2α kinase—A collaboration for regulating protein synthesis. J Biosci 1996. [DOI: 10.1007/bf02703108] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Gross M, Olin A, Hessefort S, Bender S. Control of protein synthesis by hemin. Purification of a rabbit reticulocyte hsp 70 and characterization of its regulation of the activation of the hemin-controlled eIF-2(alpha) kinase. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31708-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Pal JK, Chen JJ, London IM. Tissue distribution and immunoreactivity of heme-regulated eIF-2 alpha kinase determined by monoclonal antibodies. Biochemistry 1991; 30:2555-62. [PMID: 1672093 DOI: 10.1021/bi00223a037] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A highly purified preparation of heme-regulated inhibitor (HRI), an eIF-2 alpha kinase, from rabbit reticulocyte lysates has been used for generating monoclonal antibodies (mAB). Two hybridoma clones secreting HRI-specific antibodies (mAB A and mAB F) were obtained. Both antibodies immunoprecipitated biosynthetically labeled as well as phosphorylated HRI in reticulocyte lysates and also recognized denatured HRI in a Western blot. In in vitro protein kinase assays, preincubation of HRI with the antibodies significantly diminished both autokinase and eIF-2 alpha kinase activities. HRI from reticulocyte lysates could be quantitatively removed by immunoprecipitation with mAB F, and such HRI-depleted lysates were able to maintain protein synthesis under conditions of heme deficiency. With these monoclonal antibodies, HRI was detected only in the reticulocytes and bone marrow of anemic rabbits, among several rabbit tissues tested. The antibodies did not detect cross-reacting HRI in rat or human reticulocytes or in mouse erythroleukemic cells or human K562 cells even after induction of differentiation, although eIF-2 alpha kinase activity was detected in them. Polyclonal anti-rabbit HRI antibody detected HRI in rat reticulocytes. However, no cross-reacting HRI was detected by polyclonal antibody in human reticulocytes or other cell types tested. These findings suggest that HRI is not ubiquitous, and may be erythroid-specific, and that it is antigenically different in different species.
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Affiliation(s)
- J K Pal
- Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Cambridge 02139
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Gross M, Rubino MS. Regulation of Eukaryotic Initiation Factor-2B Activity by Polyamines and Amino Acid Starvation in Rabbit Reticulocyte Lysate. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(20)88266-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Hurst R, Schatz JR, Matts RL. Inhibition of rabbit reticulocyte lysate protein synthesis by heavy metal ions involves the phosphorylation of the alpha-subunit of the eukaryotic initiation factor 2. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)47679-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Evidence that phosphorylation of eIF-2(alpha) prevents the eIF-2B-mediated dissociation of eIF-2 X GDP from the 60 S subunit of complete initiation complexes. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)48329-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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London IM, Levin DH, Matts RL, Thomas NSB, Petryshyn R, Chen JJ. 12 Regulation of Protein Synthesis. CONTROL BY PHOSPHORYLATION PART B - SPECIFIC ENZYMES (II) BIOLOGICAL PROCESSES 1987. [DOI: 10.1016/s1874-6047(08)60263-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Gross M, Redman R, Kaplansky DA. 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. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)39391-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Michelson AM, Ernst V, Levin DH, London IM. Effects of glucose 6-phosphate and hemin on activation of heme-regulated eIF-2 alpha kinase in gel-filtered reticulocyte lysates. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)39762-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Ranu RS. Regulation of protein synthesis in rabbit reticulocyte lysates: effect of of Ca2+, Mg2+, and Mn2+ on self-phosphorylation and heterophosphorylation catalyzed by the heme-regulated and double-stranded-RNA-activated protein kinases. Biosci Rep 1982; 2:813-7. [PMID: 7171744 DOI: 10.1007/bf01114941] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The influence of divalent cations Mg2+, Mn2+, and Ca2+ on the cyclic-AMP-independent protein kinases of the heme-regulated and double-stranded-RNA-activated translational inhibitory protein kinases on self-phosphorylation and heterophosphorylation of the substrate (the 38 000-dalton subunit of initiation factor eIF-2) has been examined. Results show that Mg2+, Mn2+, and Ca2+ affect the activities of these enzymes in the following fashion. Mg2+ supports both self-phosphorylation and heterophosphorylation efficiently. Mn2+ on the other hand supports self-phosphorylation but to a lesser degree the heterophosphorylation. Ca2+ promotes neither self-phosphorylation nor heterophosphorylation.
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Kaplansky DA, Kwan A, Gross M. Effect of Met-tRNAf deacylase on polypeptide chain initiation in rabbit reticulocyte lysate. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)83838-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Wong ST, Mastropaolo W, Henshaw EC. Differential phosphorylation of soluble versus ribosome-bound eukaryotic initiation factor 2 in the Ehrlich ascites tumor cell. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34660-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Leroux A, London IM. Regulation of protein synthesis by phosphorylation of eukaryotic initiation factor 2 alpha in intact reticulocytes and reticulocyte lysates. Proc Natl Acad Sci U S A 1982; 79:2147-51. [PMID: 6954531 PMCID: PMC346147 DOI: 10.1073/pnas.79.7.2147] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Studies in intact rabbit reticulocytes and reticulocyte lysates provide further evidence of a functional role for the phosphorylation of eukaryotic initiation factor 2 alpha (eIF-2 alpha) in the regulation of initiation of protein synthesis in eukaryotic cells. In intact reticulocytes treated with isonicotinic acid hydrazide to inhibit heme synthesis, the phosphorylation of eIF-2 alpha was significantly greater than in control cells. In heme-deficient reticulocyte lysates and in lysates treated with double-stranded RNA, significant phosphorylation of eIF-2 alpha occurred prior to the onset of inhibition of protein synthesis; a large proportion, however, of the total eIF-2 alpha remained unphosphorylated. These findings indicate that a modest concentration of phosphorylated eIF-2 alpha can suffice to inhibit initiation, and they suggest that one of the factors with which eIF-2 must interact may be rate limiting, especially when eIF-2 alpha is phosphorylated.
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Flockhart DA, Corbin JD. Regulatory mechanisms in the control of protein kinases. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1982; 12:133-86. [PMID: 7039969 DOI: 10.3109/10409238209108705] [Citation(s) in RCA: 301] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Franco RS, Hogg JW, Martelo OJ. Activation and partial characterization of a human reticulocyte heme-dependent eIF-Z alpha kinase. Am J Hematol 1981; 11:9-18. [PMID: 7270549 DOI: 10.1002/ajh.2830110103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
An inhibitor of globin translation initiation that is activated under heme-deficient conditions and whose activity is associated with phosphorylation of the 38,000 dalton (alpha) subunit of the initiation factor eIF-2 has been previously described in rabbit reticulocytes. We describe here an analogous enzyme in human reticulocytes. The human enzyme can be activated in intact reticulocytes under conditions of heme synthesis inhibition or by incubation of lysates in the absence of hemin. Addition of hemin to lysates prevents activation of the eIF-2 alpha kinase. The partially purified kinase is associated with inhibition of globin synthesis in a rabbit cell-free system and phosphorylates the small subunit of highly purified rabbit eIF-2. We conclude that human reticulocytes contain a protein kinase that is analogous to the rabbit HCR and that may play a role in clinical heme deficiency states. l
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Levin D, Petryshyn R, London I. Characterization of purified double-stranded RNA-activated eIF-2 alpha kinase from rabbit reticulocytes. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69008-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Das H, Das A, Ghosh-Dastidar P, Ralston R, Yaghmai B, Roy R, Gupta N. Protein synthesis in rabbit reticulocytes. Purification and characterization of a double-stranded RNA-dependent protein synthesis inhibitor from reticulocyte lysates. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69192-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Gross M, Knish WM, Kwan A. Rabbit reticulocyte double-stranded RNA-activated protein kinase and the hemin-controlled translational repressor phosphorylate the same Mr 1500 peptide of eukaryotic initiation factor 2 alpha. FEBS Lett 1981; 125:223-6. [PMID: 7227552 DOI: 10.1016/0014-5793(81)80724-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Jagus R, Anderson WF, Safer B. The regulation of initiation of mammalian protein synthesis. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1981; 25:127-85. [PMID: 6164076 DOI: 10.1016/s0079-6603(08)60484-5] [Citation(s) in RCA: 228] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Ohtsuki K, Nakamura M, Koike T, Ishida N, Baron S. A ribosomal protein mediates eIF-2 phosphorylation by interferon-induced kinase. Nature 1980; 287:65-7. [PMID: 6157995 DOI: 10.1038/287065a0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Ernst V, Levin DH, Leroux A, London IM. Site-specific phosphorylation of the alpha subunit of eukaryotic initiation factor eIF-2 by the heme-regulated and double-stranded RNA-activated eIF-2 alpha kinases from rabbit reticulocyte lysates. Proc Natl Acad Sci U S A 1980; 77:1286-90. [PMID: 6929486 PMCID: PMC348479 DOI: 10.1073/pnas.77.3.1286] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The site specificity of phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF-2alpha) by the heme-regulated and double-stranded RNA-activated eIF-2alpha kinases were compared by phosphopeptide mapping. eIF-2alpha was maximally phosphorylated in vitro with [gamma-(32)P]ATP and either crude or partially purified preparations of the kinases. (32)P-Labeled eIF-2alpha was isolated by electrophoresis in sodium dodecyl sulfate/polyacrylamide gels. The fixed, stained, and dried polypeptide band was excised and then exhaustively digested directly in the gel slice with one of several proteases (trypsin, chymotrypsin, subtilisin, or thermolysin); the resultant [(32)P]phosphopeptides were analyzed by one-dimensional chromatography or by two-dimensional chromatography and high-voltage electrophoresis. In addition, limited proteolysis of [(32)P]eIF-2alpha contained in fixed, dried, and stained gel slices was achieved with Staphylococcus aureus protease V8, chymotrypsin, or subtilisin, and the partial (32)P-labeled cleavage products were analyzed by gel electrophoresis. Each protease produced distinct and reproducible [(32)P]phosphopeptide profiles after partial or exhaustive proteolysis of [(32)P]eIF-2alpha. With a given protease, identical [(32)P]phosphopeptide patterns were obtained whether eIF-2alpha was phosphorylated by the heme-regulated or the double-stranded RNA-activated kinase. These data indicate that, in vitro, the kinases phosphorylate sites on eIF-2alpha that are identical or proximally located in the primary sequence. In this report we also provide preliminary evidence that the two eIF-2alpha kinases activated in lysates by heme deficiency or double-stranded RNA phosphorylate site(s) of endogenous eIF-2alpha that are similar, if not identical, to the sites phosphorylated in vitro with partially purified eIF-2alpha kinase(s) and eIF-2.
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Levin DH, Petryshyn R, London IM. Characterization of double-stranded-RNA-activated kinase that phosphorylates alpha subunit of eukaryotic initiation factor 2 (eIF-2 alpha) in reticulocyte lysates. Proc Natl Acad Sci U S A 1980; 77:832-6. [PMID: 6928683 PMCID: PMC348375 DOI: 10.1073/pnas.77.2.832] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Incubation of reticulocyte lysates with low levels of double-stranded (ds) RNA (1-20 ng/ml) activates a cAMP-independent protein kinase (dsI) that phosphorylates the alpha-subunit (M(r) 38,000) of initiation factor 2 (eIF-2) and produces an inhibition of protein chain initiation similar to that caused by heme deficiency. Activation of dsI from its latent precursor takes place on the ribosomes and requires ATP. dsI can also be activated in ribosomal salt washes and in partially purified preparations of the latent precursor of dsI. In all preparations, activation is accompanied by the ds RNA-dependent phosphorylation of a polypeptide doublet that migrates as bands of 67 and 68.5 kilodaltons (67/68.5) in NaDodSO(4)/acrylamide gels. The rate of phosphorylation of these components in a ribosome salt wash is more rapid than the ds RNA-dependent phosphorylation of eIF-2alpha. Other polypeptides in the salt wash also undergo ds RNA-dependent phosphorylation, but their significance is not clear. All of these phosphorylations are prevented by high concentrations of poly(I).poly(C)(20 mug/ml), but not by an antiserum specific for the heme-regulated eIF-2alpha kinase. Both the latent and activated forms of dsI have been partially purified from a 0.5 M KCl wash of reticulocyte ribosomes. The two species have similar M(r)s ( approximately 120,000) and sedimentation coefficients ( approximately 3.75 S), which suggests that activation of dsI probably does not involve extensive changes. By comparison, the heme-regulated eIF-2alpha kinase has an M(r) of approximately 160,000 and sediments at approximately 6.6 S. However, in vitro, dsI and HRI both phosphorylate the same site(s) of eIF-2alpha. Purified dsI inhibits protein synthesis in hemin-supplemented lysates with the same kinetics induced by the addition of ds RNA; both inhibitions are reversed by eIF-2. dsI that has been activated in the salt wash and then purified does not require ds RNA for expression and no longer displays phosphorylation of the 68.5/67 doublet, which appears to occur only during activation. The data support the view that this component(s) may be the eIF-2alpha kinase activated by ds RNA.
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