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

PDI gene family

Reviewed December 2009

What are the PDI genes?

Protein disulfide isomerases are enzymes that play a critical role in protein folding. After proteins are produced, they must be folded into the correct 3-dimensional shape to function properly. Misfolded proteins may be nonfunctional, or they may clump together to form aggregates that can interfere with other cell functions.

Cells use multiple mechanisms to fold proteins into the right shape. Protein disulfide isomerases are responsible for one of these mechanisms, the formation and breakage of connections called disulfide bonds. Each disulfide bond connects two atoms of sulfur together. In proteins, sulfur atoms are part of a specific protein building block (amino acid) called cysteine. Disulfide bonds help a protein fold by connecting cysteines in different regions of the protein. These bonds stabilize the protein and give it the appropriate shape to carry out its particular function.

Protein disulfide isomerases are active in tissues and organs throughout the body. Within cells, these enzymes are found primarily in the endoplasmic reticulum (ER), a structure involved in protein processing and transport. However, studies suggest that protein disulfide isomerases are also found in other parts of the cell and may have additional functions.

Which genes are included in the PDI 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 this member of the PDI gene family: CASQ2.

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

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

  • catecholaminergic polymorphic ventricular tachycardia

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

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

  • The significance of the domains of protein disulfide isomerase for the different functions of the protein ( (University of Oulu, Finland)
  • Madame Curie Bioscience Database: Protein Folding in the ER ( (U.S. National Library of Medicine)
  • The Cell: A Molecular Approach (second edition, 2000): The Action of Protein Disulfide Isomerase (figure) ( (U.S. National Library of Medicine)
  • The Cell: A Molecular Approach (second edition, 2000): Enzymes and Protein Folding ( (U.S. National Library of Medicine)
  • Molecular Cell Biology (fourth edition, 2000): Rearrangement of Disulfide Bonds by Protein Disulfide Isomerase (figure) ( (U.S. National Library of Medicine)

What glossary definitions help with understanding the PDI gene family?

amino acid ; cell ; chaperone ; cysteine ; endoplasmic reticulum ; ER ; oxidation ; protein

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 PDI gene family.

  • Wilkinson B, Gilbert HF. Protein disulfide isomerase. Biochim Biophys Acta. 2004 Jun 1;1699(1-2):35-44. Review. (
  • Noiva R. Protein disulfide isomerase: the multifunctional redox chaperone of the endoplasmic reticulum. Semin Cell Dev Biol. 1999 Oct;10(5):481-93. Review. (
  • Wang CC. Protein disulfide isomerase assists protein folding as both an isomerase and a chaperone. Ann N Y Acad Sci. 1998 Dec 13;864:9-13. 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: December 2009
Published: February 1, 2016