Post-translational arginylation of calreticulin: a new isospecies of calreticulin component of stress granules

DECCA, MARÍA B; CARPIO, MARCOS A; BOSC, CHRISTOPHE; GALIANO, MAURICIO R; HALLAK, MARTA E

American Society for Biochemistry and Molecular Biology

Lugar: Bethesda, MD, 20814, EEUU; Año: 2007 vol. 282 p. 8237 - 8237

Post-translational arginylation consists of the covalent union of an arginine residue to a Glu, Asp, or Cys amino acid at the N-terminal position of proteins. This reaction is catalyzed by the enzyme arginyl-tRNA protein transferase. Using mass spectrometry, we have recently demonstrated in vitro the post-translational incorporation of arginine into the calcium-binding protein calreticulin (CRT). To further study arginylated CRT we raised an antibody against the peptide (RDPAIYFK) that contains an arginine followed by the first 7 N-terminal amino acids of mature rat CRT. This antibody specifically recognizes CRT obtained from rat soluble fraction that was arginylated in vitro and also recognizes endogenous arginylated CRT from NIH 3T3 cells in culture, indicating that CRT arginylation takes place in living cells. Using this antibody we found that arginylation of CRT is Ca2+-regulated. In vitro and in NIH 3T3 cells in culture, the level of arginylated CRT increased with the addition