Phosphoregulated FMRP phase separation models activity-dependent translation through bidirectional control of mRNA granule formation.
Proc Natl Acad Sci U S A
; 116(10): 4218-4227, 2019 03 05.
Article
em En
| MEDLINE
| ID: mdl-30765518
ABSTRACT
Activity-dependent translation requires the transport of mRNAs within membraneless protein assemblies known as neuronal granules from the cell body toward synaptic regions. Translation of mRNA is inhibited in these granules during transport but quickly activated in response to neuronal stimuli at the synapse. This raises an important question how does synaptic activity trigger translation of once-silenced mRNAs? Here, we demonstrate a strong connection between phase separation, the process underlying the formation of many different types of cellular granules, and in vitro inhibition of translation. By using the Fragile X Mental Retardation Protein (FMRP), an abundant neuronal granule component and translational repressor, we show that FMRP phase separates in vitro with RNA into liquid droplets mediated by its C-terminal low-complexity disordered region (i.e., FMRPLCR). FMRPLCR posttranslational modifications by phosphorylation and methylation have opposing effects on in vitro translational regulation, which corroborates well with their critical concentrations for phase separation. Our results, combined with bioinformatics evidence, are supportive of phase separation as a general mechanism controlling activity-dependent translation.
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MEDLINE
Assunto principal:
Sinapses
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Transcrição Gênica
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RNA Mensageiro
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Processamento de Proteína Pós-Traducional
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Grânulos Citoplasmáticos
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Proteína do X Frágil da Deficiência Intelectual
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article