Post-translational arginylation in the bovine lens.
This study demonstrates post-translational arginylation of bovine serum albumin and endogenous lens proteins by bovine lens arginyl-tRNA:protein transferase. This reaction has been proposed to be the first step in marking specific proteins for degradation by the non-lysosomal, ATP-dependent, ubiquitin-mediated proteolytic pathway. The transferase was obtained by the method used for isolation of the same enzyme from reticulocytes (Ferber and Ciechanover, 1987, Nature 326, 808-11). Incorporation of [3H]Arg was linear for at least 2 hr at 37 degrees C. The amount of incorporation was directly proportional to the amount of lens enzyme or substrate added. Arginylation was ATP-dependent. A requirement for tRNA was demonstrated by inhibition upon pretreatment of the enzyme preparation with nuclease to hydrolyse endogenous tRNA, and restoration of activity upon replacement of tRNA. [3H]Leu, [3H]Lys and [3H]His were not incorporated, demonstrating specificity of the reaction for arginine. This is the first demonstration of post-translational modification of proteins by arginylation in the lens.
Wagner
B J
BJ
Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, Newark 07103.
Margolis
J W
JW
D000217:Acyltransferases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D019881:Aminoacyltransferases; D000818:Animals; D001120:Arginine / Q000378:metabolism; D002417:Cattle; D003459:Crystallins / Q000096:biosynthesis; D007908:Lens, Crystalline / Q000201:enzymology*; D010441:Peptide Chain Elongation, Translational; D011499:Protein Processing, Post-Translational; D012347:RNA, Transfer, Arg / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000096:biosynthesis; D013379:Substrate Specificity
D003459:Crystallins; D012347:RNA, Transfer, Arg; D012710:Serum Albumin, Bovine; D000255:Adenosine Triphosphate; D001120:Arginine; D000217:Acyltransferases; D019881:Aminoacyltransferases; C019727:arginyltransferase