Analysis of sigma32 mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response.
Proc Natl Acad Sci U S A
; 104(45): 17638-43, 2007 Nov 06.
Article
en En
| MEDLINE
| ID: mdl-17968012
ABSTRACT
Protein quality control is accomplished by inducing chaperones and proteases in response to an altered cellular folding state. In Escherichia coli, expression of chaperones and proteases is positively regulated by sigma32. Chaperone-mediated negative feedback control of sigma32 activity allows this transcription factor to sense the cellular folding state. We identified point mutations in sigma32 altered in feedback control. Surprisingly, such mutants are resistant to inhibition by both the DnaK/J and GroEL/S chaperones in vivo and also show dramatically increased stability. Further characterization of the most defective mutant revealed that it has almost normal binding to chaperones and RNA polymerase and is competent for chaperone-mediated inactivation in vitro. We suggest that the mutants identify a regulatory step downstream of chaperone binding that is required for both inactivation and degradation of sigma32.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Contexto en salud:
3_ND
Problema de salud:
3_neglected_diseases
/
3_zoonosis
Asunto principal:
Factor sigma
/
Escherichia coli
/
Proteínas de Choque Térmico
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2007
Tipo del documento:
Article
País de afiliación:
Estados Unidos