Association of glucose‐regulated protein (grp78) with human keratin 8

FEBS Letters

Omary, M.Bishr²  Liao, Jian¹  Price, Daniel² 

[1] Clontech Laboratories Inc., 1020 East Meadow Circle, Palo Alto, CA 94303, USA;VA Palo Alto Health Care System, 3801 Miranda Avenue, 154J, Palo Alto, CA 94304, USA

关键词: Keratin;    Intermediate filament;    Glucose-regulated protein;    grp78;    Stress protein;    hsp70;    Emp;    Empigen BB;    ER;    endoplasmic reticulum;    IF;    intermediate filament(s);    K;    keratin;    mAb;    monoclonal antibody;    NP40;    Nonidet P40;    PAGE;    polyacrylamide gel electrophoresis;    PVDF;    polyvinylidene difluoride;   

DOI  :  10.1016/S0014-5793(97)01315-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Keratin polypeptides 8 and 18 (K8/18) are intermediate filament proteins that are expressed in ‘simple-type’ epithelial cells. They associate with several proteins including the 70 kDa cytoplasmic heat shock proteins (hsp70). We identified the human 78 kDa glucose-regulated protein (grp78) as a keratin-associated protein. Keratin-grp78 association was noted after co-immunoprecipitation of K8/18 from HT29 detergent solubilized cell lysates, and appears to involve non-posttranslationally modified grp78. The grp78-K8/18 association is induced by culturing cells in the presence of tunicamycin or after glucose starvation. K8/18-bound grp78 can be dissociated by Mg-ATP and the association can be reconstituted in vitro using purified grp78, then redissociated again by Mg-ATP. Binding of grp78 occurs preferentially with K8, and when reconstituted does not depend on the posttranslational modification state of K8/18. Co-incubation of K8/18 with hsp70 and grp78 shows preferential association with hsp70. Our results demonstrate a direct association of grp78 with K8 under conditions that induce grp78 expression.

【 授权许可】

Unknown