Acylation of proteins with myristic acid occurs cotranslationally.
Several proteins of viral and cellular origin are acylated with myristic acid early during their biogenesis. To investigate the possibility that myristylation occurred cotranslationally, the BC3H1 muscle cell line, which contains a broad array of myristylated proteins, was pulse-labeled with [3H]myristic acid. Nascent polypeptide chains covalently associated with transfer RNA were isolated subsequently by ion-exchange chromatography. [3H]Myristate was attached to nascent chains through an amide linkage and was identified by thin-layer chromatography after its release from nascent chains by acid methanolysis. Inhibition of cellular protein synthesis with puromycin resulted in cessation of [3H]myristate-labeling of nascent chains, in agreement with the dependence of this modification on protein synthesis in vivo. These data represent a direct demonstration that myristylation of proteins is a cotranslational modification.
Department of Biochemistry and Molecular Biology, University of Texas, M.D. Anderson Hospital and Tumor Institute at Houston 77030.
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Wilcox
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Hu
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Olson
D000215:Acylation; D000818:Animals; D002460:Cell Line; D007700:Kinetics; D008715:Methionine / Q000378:metabolism; D009132:Muscles; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D013462:Sulfur Radioisotopes; D014316:Tritium
D009227:Myristic Acids; D011506:Proteins; D013462:Sulfur Radioisotopes; D019814:Myristic Acid; D014316:Tritium; D008715:Methionine