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

KIF gene family

Reviewed March 2011

What are the KIF genes?

Genes in the KIF superfamily provide instructions for making proteins called kinesins. Researchers have identified 45 different kinesins in humans and other mammals. These proteins are sorted into 14 subfamilies, known as kinesin-1 through kinesin-14, based on differences in their structure.

Kinesins are essential for the transport of materials within cells. These proteins function like freight trains that transport cargo, and their structure is suited for this cargo-carrying function. One end of the protein, called the motor domain, provides power to move the protein and its cargo along a track-like system made from structures called microtubules. The other end of the protein attaches (binds) to specific cargo, such as groups of proteins or other cell materials, for transport. The two ends of each kinesin are connected by a flexible region known as the stalk. The structure of the cargo-binding region and the stalk varies significantly among the kinesins, allowing these proteins to bind to and transport many different kinds of materials.

Kinesins transport materials within many types of cells. These proteins have been studied extensively in nerve cells (neurons), where they carry substances needed for the development, function, and survival of these cells. Kinesins are also involved in intraflagellar transport, which is the movement of substances in cell structures called cilia and flagella. These finger-like projections stick out from the surface of cells and are involved in cell movement and chemical signaling. Kinesins are also thought to play a role in the two major types of cell division, mitosis and meiosis.

Mutations in several KIF genes have been associated with human disease. For example, mutations in the KIF21A gene cause an eye disorder called congenital fibrosis of the extraocular muscles. A movement disorder known as spastic paraplegia 10 results from changes in the KIF5A gene. Additionally, a single mutation in the KIF1B gene has been found to cause Charcot-Marie-Tooth disease type 2A, an inherited condition that affects the nervous system. Studies in other animals suggest that KIF genes may also play a role in other neurological disorders (such as Alzheimer disease) and cancer.

Which genes are included in the KIF 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 KIF gene family: KIF1B and KIF21A.

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

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

  • Charcot-Marie-Tooth disease
  • congenital fibrosis of the extraocular muscles
  • neuroblastoma
  • nonsyndromic paraganglioma

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

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

  • The Cell A Molecular Approach (second edition, 2000): Identification of Microtubule Motor Proteins ( (U.S. National Library of Medicine)
  • Molecular Cell Biology (fourth edition, 2000): Kinesin, Dynein, and Intracellular Transport ( (U.S. National Library of Medicine)
  • Molecular Biology of the Cell (fourth edition, 2002): There Are Two Types of Microtubule Motor Proteins: Kinesins and Dyneins ( (U.S. National Library of Medicine)
  • Kinesin Home Page ( (Duke University)

What glossary definitions help with understanding the KIF gene family?

cancer ; cell ; cell division ; congenital ; domain ; extraocular muscles ; fibrosis ; gene ; inherited ; intracellular ; meiosis ; mitosis ; motor ; mutation ; nervous system ; neurological ; paraplegia ; 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 KIF gene family.

  • Hirokawa N, Takemura R. Kinesin superfamily proteins and their various functions and dynamics. Exp Cell Res. 2004 Nov 15;301(1):50-9. Review. (
  • Miki H, Okada Y, Hirokawa N. Analysis of the kinesin superfamily: insights into structure and function. Trends Cell Biol. 2005 Sep;15(9):467-76. Review. (
  • Seog DH, Lee DH, Lee SK. Molecular motor proteins of the kinesin superfamily proteins (KIFs): structure, cargo and disease. J Korean Med Sci. 2004 Feb;19(1):1-7. Review. (
  • Hirokawa N, Noda Y. Intracellular transport and kinesin superfamily proteins, KIFs: structure, function, and dynamics. Physiol Rev. 2008 Jul;88(3):1089-118. doi: 10.1152/physrev.00023.2007. Review. (
  • Mandelkow E, Mandelkow EM. Kinesin motors and disease. Trends Cell Biol. 2002 Dec;12(12):585-91. 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: March 2011
Published: February 8, 2016