Effects of Ca2+ and ionophore A23187 on protein synthesis in intact rabbit reticulocytes.
1. Amino acid incorporation in intact rabbit reticulocytes was unaffected by depletion of Ca2+ with EGTA. 2. The Ca2+ ionophore A23187 strongly inhibited incorporation in reticulocytes incubated in 1 mM Ca2+ but not in EGTA. Polysomal profiles and average ribosomal transit times of cells treated with Ca2+ ionophore at 1 mM Ca2+ were characteristic of translational elongation block. 3. The behavior of reticulocytes with respect to Ca2+ and A23187 contrasts with that of nucleated cells possessing endoplasmic reticulum in which protein synthesis is inhibited at translational initiation by either Ca2+ depletion or by exposure to Ca2+ ionophore.
Wong
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Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854.
Brostrom
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Brostrom
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D000818:Animals; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D002499:Centrifugation, Density Gradient; D004533:Egtazic Acid / Q000494:pharmacology; D005260:Female; D007930:Leucine / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism
D000001:Calcimycin; D004533:Egtazic Acid; D007930:Leucine; D002118:Calcium