The function of protein carboxylmethyltransferase in eucaryotic cells.
Protein carboxylmethyltransferase (PCM) is an enzyme whose function in eucaryotic cells remains controversial. Early studies suggested that protein carboxylmethylation subserved a regulatory, post-translational role in such diverse processes as secretion, neuronal receptor function, chemotaxis, and cellular differentiation. Later work strongly supported a totally unrelated role for this enzyme, i.e., the repair of spontaneously altered aspartate residues in cellular proteins. More recent evidence, however, suggests that a distinct, membrane-associated PCM catalyzes the methylation of alpha-carboxyl groups of C-terminal cysteines on discrete proteins. In view of these recent investigations, the data supporting a regulatory role for PCM are critically discussed and re-evaluated. There now appears to be compelling evidence that PCM(s) subserves both repair and regulatory functions in eucaryotic cells, catalyzing post-translational modifications of proteins involved in cell division, hormonal secretion, calmodulin-associated events and the interaction of guanyl nucleotide-linked proteins with the cell membrane.
Barten
D M
DM
Department of Pediatrics, University of Minnesota Medical School, Minneapolis.
O'Dea
R F
RF
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D002477:Cells / Q000201:enzymology*; D005057:Eukaryotic Cells / Q000201:enzymology*; D011496:Protein Methyltransferases / Q000502:physiology*
D011496:Protein Methyltransferases