The arginylation-dependent association of calreticulin with stress granules is regulated by calcium.
Biochem J
; 429(1): 63-72, 2010 Jul 01.
Article
em En
| MEDLINE
| ID: mdl-20423325
ABSTRACT
Post-translational modifications of proteins are important for the regulation of cell functions; one of these modifications is post-translational arginylation. In the present study, we show that cytoplasmic CRT (calreticulin) is arginylated by ATE1 (arginyl-tRNA protein transferase). We also show that a pool of CRT undergoes retrotranslocation from the ER (endoplasmic reticulum) to the cytosol, because in CRT-knockout cells transfected with full-length CRT (that has the signal peptide), cytoplasmic CRT appears as a consequence of its expression and processing in the ER. After the cleavage of the signal peptide, an N-terminal arginylatable residue is revealed prior to retrotranslocation to the cytoplasm where arginylation takes place. SGs (stress granules) from ATE1-knockout cells do not contain CRT, indicating that CRT arginylation is required for its association to SGs. Furthermore, R-CRT (arginylated CRT) in the cytoplasm associates with SGs in cells treated with several stressors that lead to a reduction of intracellular Ca2+ levels. However, in the presence of stressors that do not affect Ca2+ levels, R-CRT is not recruited to these loci despite the fact that SGs are formed, demonstrating Ca2+-dependent R-CRT association to SGs. We conclude that post-translational arginylation of retrotranslocated CRT, together with the decrease in intracellular Ca2+, promotes the association of CRT to SGs.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Arginina
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Estresse Fisiológico
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Processamento de Proteína Pós-Traducional
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Cálcio
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Aminoaciltransferases
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Grânulos Citoplasmáticos
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Calreticulina
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Argentina