Identification of Mrj, a DnaJ/Hsp40 family protein, as a keratin 8/18 filament regulatory protein.
J Biol Chem
; 275(44): 34521-7, 2000 Nov 03.
Article
en En
| MEDLINE
| ID: mdl-10954706
ABSTRACT
To elucidate the function of keratins 8 and 18 (K8/18), major components of the intermediate filaments of simple epithelia, we searched for K8/18-binding proteins by screening a yeast two-hybrid library. We report here that human Mrj, a DnaJ/Hsp40 family protein, directly binds to K18. Among the interactions between DnaJ/Hsp40 family proteins and various intermediate filament proteins that we tested using two-hybrid methods, Mrj specifically interacted with K18. Immunostaining with anti-Mrj antibody showed that Mrj colocalized with K8/18 filaments in HeLa cells. Mrj was immunoprecipitated not only with K18, but also with the stress-induced and constitutively expressed heat shock protein Hsp/c70. Mrj bound to K18 through its C terminus and interacted with Hsp/c70 via its N terminus, which contains the J domain. Microinjection of anti-Mrj antibody resulted in the disorganization of K8/18 filaments, without effects on the organization of actin filaments and microtubules. Taken together, these results suggest that Mrj may play an important role in the regulation of K8/18 filament organization as a K18-specific co-chaperone working together with Hsp/c70.
Buscar en Google
Base de datos:
MEDLINE
Asunto principal:
Filamentos Intermedios
/
Chaperonas Moleculares
/
Queratinas
/
Proteínas del Tejido Nervioso
Tipo de estudio:
Diagnostic_studies
Idioma:
En
Revista:
J Biol Chem
Año:
2000
Tipo del documento:
Article