Localization and function in endoplasmic reticulum stress tolerance of ERdj3, a new member of Hsp40 family protein.
Heat shock protein 40 (Hsp40) family proteins are known to bind to Hsp70 through their J-domain and regulate the function of Hsp70 by stimulating its adenosine triphosphatase activity. In the endoplasmic reticulum (ER), there are 5 Hsp40 family proteins known so far, 3 of which were recently identified. In this report, one of the novel Hsp40 cochaperones, ERdj3, was characterized in terms of its subcellular localization, stress response, and stress tolerance of cells. By using ERdj3-specific polyclonal antibody, endogenous ERdj3 protein was shown to reside in the ER as gene transfer-mediated exogenous ERdj3. Analysis of the expression level of endogenous ERdj3 protein revealed its moderate induction in response to various ER stressors, indicating its possible action as a stress protein in the ER. Subsequently, we analyzed whether this molecule was involved in ER stress tolerance of cells, as was the case with the ER-resident Hsp70 family protein BiP. Although overexpression of ERdj3 by gene transfection could not strengthen ER stress tolerance of neuroblastoma cells, reduction of ERdj3 expression by small interfering ribonucleic acid decreased the tolerance of cells, indicating that ERdj3 might have just a marginal role in the ER stress resistance of neuroblastoma cells. In contrast, overexpression of ERdj3 notably suppressed vero toxin-induced cell death. These data suggest that ERdj3 might have diverse roles in the ER, including that of the molecular cochaperone of BiP and an as yet unknown protective action against vero toxin.
Nakanishi
Katsuya
K
Department of Pathology, Sapporo Medical University School of Medicine, S-1, W-17, Chuo-ku, Sapporo 060-8556, Japan.
Kamiguchi
Kenjiro
K
Torigoe
Toshihiko
T
Nabeta
Chika
C
Hirohashi
Yoshihiko
Y
Asanuma
Hiroko
H
Tobioka
Hirotoshi
H
Koge
Norie
N
Harada
Oi
O
Tamura
Yasuaki
Y
Nagano
Hideki
H
Yano
Shoki
S
Chiba
Susumu
S
Matsumoto
Hiroyuki
H
Sato
Noriyuki
N
D000595:Amino Acid Sequence; D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D050956:HSP40 Heat-Shock Proteins; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D034622:RNA Interference; D022603:Shiga Toxins / Q000494:pharmacology; D013312:Stress, Physiological / Q000235:genetics / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology; D014162:Transfection; D014415:Tunicamycin / Q000494:pharmacology
C494647:DNAJB1 protein, human; C494648:DNAJB11 protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D022603:Shiga Toxins; D014415:Tunicamycin; D019284:Thapsigargin