Cloning and characterization of a new soluble murine J-domain protein that stimulates BiP, Hsc70 and DnaK ATPase activity with different efficiencies.
Hsp70s perform many functions in the cell through their ATPase activity that is stimulated by a genuine partner that contains a highly conserved so called J-domain. Here we report the cloning and characterization of a new J-domain protein named MmDjC7. The complete cDNA encodes a putative soluble 22 kDa protein that contains a conserved J-domain, but lacks the G/F- and C-rich regions found in the bacterial Escherichia coli DnaJ. Northern analysis revealed that mmDjC7 mRNA (0.9 kb) is most abundant in the heart and liver tissues. Recombinant hexahistidine tagged MmDjC7 (25 kDa) was efficiently expressed in E. coli and purified to homogeneity. MmDjC7 stimulates the ATPase activity of murine BiP, Hsc70 and E. coli DnaK, albeit with very different molar ratios that vary from 1:2 (for BiP/MmDjC7) to 1:10 (for DnaK/MmDjC7). MmDjC7 thus appears to be a new J-domain protein that can possibly interact with more than one Hsp70.
Kroczynska
B
B
Department of Medicinal Chemistry and Pharmacognosy, Molecular Biology Research Building, University of Illinois at Chicago, USA.
Blond
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SY
D000251:Adenosine Triphosphatases / Q000187:drug effects / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000187:drug effects / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004305:Dose-Response Relationship, Drug; D000091342:Endoplasmic Reticulum Chaperone BiP; D029968:Escherichia coli Proteins; D015870:Gene Expression; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism; D006360:Heat-Shock Proteins; D051379:Mice; D018832:Molecular Chaperones / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D011506:Proteins / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution
D002352:Carrier Proteins; D018076:DNA, Complementary; D000091342:Endoplasmic Reticulum Chaperone BiP; D029968:Escherichia coli Proteins; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C494372:Hspa8 protein, mouse; C437716:MmDjC7 protein, mouse; D018832:Molecular Chaperones; D011506:Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli