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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

DNAJ gene family

Reviewed November 2007

What are the DNAJ genes?

Genes in the DNAJ family provide instructions for making proteins that play a role in various cellular functions, such as proper protein folding, protein transport, and the cell's response to stress. DNAJ proteins are active in cells and tissues throughout the body.

The main work of DNAJ proteins is protein folding. After proteins are produced, they must be folded into the correct 3-dimensional shape to function properly. Proteins that help with this 3-dimensional folding are called chaperones. The role of a chaperone is to bind to unfolded or partially folded proteins, prevent misfolding, and assemble or disassemble multi-protein structures. DNAJ proteins are known as co-chaperones because they help another family of chaperones (DNAKs) with protein folding. DNAJ and DNAK proteins must work together to facilitate protein folding.

Researchers have found three types of DNAJ proteins. All DNAJ family members have a region of 70 protein building blocks (amino acids) known as the J-domain, which is the site of interaction between DNAJ proteins and DNAK proteins. Type I DNAJ proteins are considered true DNAJ proteins, while types II and III are usually referred to as DNAJ-like proteins. Most of the genes in this family are designated by the letters DNAJ (J for the J-domain) and an additional letter indicating the subgroup to which they belong. The subgroup designation is based on the type of DNAJ protein (type I is A, type II is B, type III is C). They also receive a number to designate the specific gene within the subgroup, for example DNAJC19. DNAJ proteins are also known as Hsp40s (heat shock protein 40); DNAK proteins also are referred to as Hsp70s.

Which genes are included in the DNAJ gene family?

The HUGO Gene Nomenclature Committee (HGNC) provides an index of gene families ( and their member genes.

Genetics Home Reference summarizes the normal function and health implications of these members of the DNAJ gene family: DNAJC5 and DNAJC19.

What conditions are related to genes in the DNAJ gene family?

Genetics Home Reference includes these conditions related to genes in the DNAJ gene family:

  • dilated cardiomyopathy with ataxia syndrome
  • Kufs disease

Where can I find additional information about the DNAJ gene family?

You may find the following resources about the DNAJ gene family helpful.

  • Molecular Biology of the Cell (4th edition, 2002): From RNA to Protein (
  • Eurekah Bioscience Collection: Chaperones and Thermotolerance ( (U.S. National Library of Medicine)

What glossary definitions help with understanding the DNAJ gene family?

acids ; ADP ; ATP ; cell ; chaperone ; domain ; gene ; hydrolysis ; protein ; shock ; stress

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


These sources were used to develop the Genetics Home Reference summary for the DNAJ gene family.

  • Walsh P, Bursać D, Law YC, Cyr D, Lithgow T. The J-protein family: modulating protein assembly, disassembly and translocation. EMBO Rep. 2004 Jun;5(6):567-71. Review. (
  • Nicoll WS, Boshoff A, Ludewig MH, Hennessy F, Jung M, Blatch GL. Approaches to the isolation and characterization of molecular chaperones. Protein Expr Purif. 2006 Mar;46(1):1-15. Epub 2005 Sep 8. Review. (
  • Ohtsuka K, Hata M. Molecular chaperone function of mammalian Hsp70 and Hsp40--a review. Int J Hyperthermia. 2000 May-Jun;16(3):231-45. Review. (
  • Suh WC, Lu CZ, Gross CA. Structural features required for the interaction of the Hsp70 molecular chaperone DnaK with its cochaperone DnaJ. J Biol Chem. 1999 Oct 22;274(43):30534-9. (
  • Greene MK, Maskos K, Landry SJ. Role of the J-domain in the cooperation of Hsp40 with Hsp70. Proc Natl Acad Sci U S A. 1998 May 26;95(11):6108-13. (
  • Suh WC, Burkholder WF, Lu CZ, Zhao X, Gottesman ME, Gross CA. Interaction of the Hsp70 molecular chaperone, DnaK, with its cochaperone DnaJ. Proc Natl Acad Sci U S A. 1998 Dec 22;95(26):15223-8. (
  • Hennessy F, Cheetham ME, Dirr HW, Blatch GL. Analysis of the levels of conservation of the J domain among the various types of DnaJ-like proteins. Cell Stress Chaperones. 2000 Oct;5(4):347-58. (
  • Genevaux P, Schwager F, Georgopoulos C, Kelley WL. Scanning mutagenesis identifies amino acid residues essential for the in vivo activity of the Escherichia coli DnaJ (Hsp40) J-domain. Genetics. 2002 Nov;162(3):1045-53. (
  • Cheetham ME, Caplan AJ. Structure, function and evolution of DnaJ: conservation and adaptation of chaperone function. Cell Stress Chaperones. 1998 Mar;3(1):28-36. Review. (
  • Hennessy F, Nicoll WS, Zimmermann R, Cheetham ME, Blatch GL. Not all J domains are created equal: implications for the specificity of Hsp40-Hsp70 interactions. Protein Sci. 2005 Jul;14(7):1697-709. Review. (
  • Laufen T, Mayer MP, Beisel C, Klostermeier D, Mogk A, Reinstein J, Bukau B. Mechanism of regulation of hsp70 chaperones by DnaJ cochaperones. Proc Natl Acad Sci U S A. 1999 May 11;96(10):5452-7. (
  • Qiu XB, Shao YM, Miao S, Wang L. The diversity of the DnaJ/Hsp40 family, the crucial partners for Hsp70 chaperones. Cell Mol Life Sci. 2006 Nov;63(22):2560-70. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: November 2007
Published: November 30, 2015