The arginylation-dependent association of calreticulin with stress granules is regulated by calcium.

MARCOS CARPIO; CECILIA LOPEZ SAMBROOKS; EDITH S. DURAND; MARTA ELENA HALLAK

PORTLAND PRESS LTD

Lugar: PORTLAND PRESS LTD; Año: 2010 vol. 429 p. 63 - 63

ost-translational modifications of proteins are important forthe regulation of cell functions; one of these modifications ispost-translational arginylation. In the present study, we showthat cytoplasmic CRT (calreticulin) is arginylated by ATE1(arginyl-tRNA protein transferase). We also show that a poolof CRT undergoes retrotranslocation from the ER (endoplasmicreticulum) to the cytosol, because in CRT-knockout cellstransfected with full-length CRT (that has the signal peptide),cytoplasmic CRT appears as a consequence of its expressionand processing in the ER. After the cleavage of the signalpeptide, an N-terminal arginylatable residue is revealed priorto retrotranslocation to the cytoplasm where arginylation takesplace. SGs (stress granules) from ATE1-knockout cells do notcontain CRT, indicating that CRT arginylation is required for itsassociation to SGs. Furthermore, R-CRT (arginylated CRT) in