The mRNA-capping enzyme localizes to stress granules in the cytoplasm and maintains cap homeostasis of target mRNAs.
J Cell Sci
; 137(11)2024 06 01.
Article
em En
| MEDLINE
| ID: mdl-38841902
ABSTRACT
The model of RNA stability has undergone a transformative shift with the revelation of a cytoplasmic capping activity that means a subset of transcripts are recapped autonomously of their nuclear counterparts. The present study demonstrates nucleo-cytoplasmic shuttling of the mRNA-capping enzyme (CE, also known as RNA guanylyltransferase and 5'-phosphatase; RNGTT), traditionally acknowledged for its nuclear localization and functions, elucidating its contribution to cytoplasmic capping activities. A unique nuclear export sequence in CE mediates XPO1-dependent nuclear export of CE. Notably, during sodium arsenite-induced oxidative stress, cytoplasmic CE (cCE) congregates within stress granules (SGs). Through an integrated approach involving molecular docking and subsequent co-immunoprecipitation, we identify eIF3b, a constituent of SGs, as an interactive associate of CE, implying that it has a potential role in guiding cCE to SGs. We measured the cap status of specific mRNA transcripts from U2OS cells that were non-stressed, stressed and recovered from stress, which indicated that cCE-target transcripts lost their caps during stress but remarkably regained cap stability during the recovery phase. This comprehensive study thus uncovers a novel facet of cytoplasmic CE, which facilitates cellular recovery from stress by maintaining cap homeostasis of target mRNAs.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
RNA Mensageiro
/
Citoplasma
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Grânulos de Estresse
/
Homeostase
Limite:
Humans
Idioma:
En
Revista:
J Cell Sci
Ano de publicação:
2024
Tipo de documento:
Article