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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2004-3-29
pubmed:abstractText
Type I DnaJs comprise one type of Hsp70 cochaperones. Previously, we showed that two type I DnaJ cochaperones, DjA1 (HSDJ/Hdj-2/Rdj-1/dj2) and DjA2 (cpr3/DNAJ3/Rdj-2/dj3), are important for mitochondrial protein import and luciferase refolding. Another type I DnaJ homolog, DjA4 (mmDjA4/dj4), is highly expressed in heart and testis, and the coexpression of Hsp70 and DjA4 protects against heat stress-induced cell death. Here, we have studied the chaperone functions of DjA4 by assaying the refolding of chemically or thermally denatured luciferase, suppression of luciferase aggregation, and the ATPase of Hsp70s, and compared these activities with those of DjA2. DjA4 stimulates the hydrolysis of ATP by Hsp70. DjA2, but not DjA4, together with Hsp70 caused denatured luciferase to refold efficiently. Together with Hsp70, both DjA2 and DjA4 are efficient in suppressing luciferase aggregation. bag-1 further stimulates ATP hydrolysis and protein refolding by Hsp70 plus DjA2 but not by Hsp70 plus DjA4. Hsp70-2, a testis-specific Hsp70 family member, behaves very similarly to Hsp70 in all these assays. Thus, Hsp70 and Hsp70-2 have similar activities in vitro, and DjA2 and DjA4 can function as partner cochaperones of Hsp70 and Hsp70-2. However, DjA4 is not functionally equivalent in modulating Hsp70s.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-924X
pubmed:author
pubmed:issnType
Print
pubmed:volume
135
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
193-200
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:15047721-Adenosine Triphosphatases, pubmed-meshheading:15047721-Adenosine Triphosphate, pubmed-meshheading:15047721-Animals, pubmed-meshheading:15047721-Cell Survival, pubmed-meshheading:15047721-HSP40 Heat-Shock Proteins, pubmed-meshheading:15047721-HSP70 Heat-Shock Proteins, pubmed-meshheading:15047721-Heat-Shock Proteins, pubmed-meshheading:15047721-Hot Temperature, pubmed-meshheading:15047721-Humans, pubmed-meshheading:15047721-Immunohistochemistry, pubmed-meshheading:15047721-Male, pubmed-meshheading:15047721-Mice, pubmed-meshheading:15047721-Mitochondria, pubmed-meshheading:15047721-Molecular Chaperones, pubmed-meshheading:15047721-Protein Denaturation, pubmed-meshheading:15047721-Protein Folding, pubmed-meshheading:15047721-Testis, pubmed-meshheading:15047721-Time Factors
pubmed:year
2004
pubmed:articleTitle
Modulation of chaperone activities of Hsp70 and Hsp70-2 by a mammalian DnaJ/Hsp40 homolog, DjA4.
pubmed:affiliation
Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto 860-8556.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't