title: A crucial role of mitochondrial Hsp40 in preventing dilated cardiomyopathy.
abstract: Many heat-shock proteins (Hsp) are members of evolutionarily conserved families of chaperone proteins that inhibit the aggregation of unfolded polypeptides and refold denatured proteins, thereby remedying phenotypic effects that may result from protein aggregation or protein instability. Here we report that the mitochondrial chaperone Hsp40, also known as Dnaja3 or Tid1, is differentially expressed during cardiac development and pathological hypertrophy. Mice deficient in Dnaja3 developed dilated cardiomyopathy (DCM) and died before 10 weeks of age. Progressive respiratory chain deficiency and decreased copy number of mitochondrial DNA were evident in cardiomyocytes lacking Dnaja3. Profiling of Dnaja3-interacting proteins identified the alpha-subunit of DNA polymerase gamma (Polga) as a client protein. These findings suggest that Dnaja3 is crucial for mitochondrial biogenesis, at least in part, through its chaperone activity on Polga and provide genetic evidence of the necessity for mitochondrial Hsp40 in preventing DCM.
authors.affiliation: Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037-1000, USA.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hayashi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Imanaka-Yoshida
authors.forename: Toshimichi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Malcolm
authors.initials: M
authors.lastname: Wood
authors.forename: Colleen
authors.initials: C
authors.lastname: Fearns
authors.forename: Revati J
authors.initials: RJ
authors.lastname: Tatake
authors.forename: Jiing-Dwan
authors.initials: JD
authors.lastname: Lee
mesh_terms: D000818:Animals; D001011:Aorta / Q000473:pathology; D002311:Cardiomyopathy, Dilated / Q000473:pathology* / Q000517:prevention & control; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D000074002:DNA Polymerase gamma; D004272:DNA, Mitochondrial / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism; D019143:Evolution, Molecular; D049452:Green Fluorescent Proteins / Q000378:metabolism; D050956:HSP40 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D020673:Protein Renaturation; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection
chemical_list: D004272:DNA, Mitochondrial; C120664:DNAJA3 protein, human; C485636:Dnaja3 protein, mouse; D050956:HSP40 Heat-Shock Proteins; D049452:Green Fluorescent Proteins; D004247:DNA; D003576:Electron Transport Complex IV; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; C413027:POLG protein, human; C498803:Polg protein, mouse