A predicted unstructured C-terminal loop domain in SIRT1 is required for cathepsin B cleavage.
J Cell Sci
; 131(16)2018 08 20.
Article
em En
| MEDLINE
| ID: mdl-30054388
ABSTRACT
The C-terminus of SIRT1 can be cleaved by cathepsin B at amino acid H533 to generate a lower-functioning, N-terminally intact 75â
kDa polypeptide (75SIRT1) that might be involved in age-related pathologies. However, the mechanisms underlying cathepsin B docking to and cleavage of SIRT1 are unclear. Here, we first identified several 75SIRT1 variants that are augmented with aging correlatively with increased cathepsin B levels in various mouse tissues, highlighting the possible role of this cleavage event in age-related pathologies. Then, based on H533 point mutation and structural modeling, we generated a functionally intact ΔSIRT1 mutant, lacking the internal amino acids 528-543 (a predicted C-terminus loop domain), which exhibits resistance to cathepsin B cleavage in vitro and in cell cultures. Finally, we showed that cells expressing ΔSIRT1 under pro-inflammatory stress are more likely to undergo caspase 9- dependent apoptosis than those expressing 75SIRT1. Thus, our data suggest that the 15-amino acid predicted loop motif embedded in the C-terminus of SIRT1 is susceptible to proteolytic cleavage by cathepsin B, leading to the formation of several N-terminally intact SIRT1 truncated variants in various aging mouse tissues.This article has an associated First Person interview with the first author of the paper.
Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Catepsina B
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Domínios e Motivos de Interação entre Proteínas
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Sirtuína 1
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Proteólise
Tipo de estudo:
Prognostic_studies
/
Risk_factors_studies
Limite:
Animals
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Female
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Humans
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Male
Idioma:
En
Revista:
J Cell Sci
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Israel