Kinesin

Function

Kinesins are eukaryotic motor proteins which move along microtubules^[1]. Kinesin (KIF) is a dimer consisting of 2 heavy chains and two light chains. The heavy chain contains the N-terminal globular motor domain (MD) responsible for the motor activity of kinesin, a central flexible neck linker (FNL) coiled-coil stalk which intertwines to form the dimer and a small globular C-terminal domain which interacts with other proteins like the kinesin light chain. The light chain (KLC) forms the tail region. The KLC contains a cargo binding domain which is called TPR (Tetratricopeptide repeat). The KIFs are named by their gene number. KIF contains a forkhead-associated domain (FHA) which is involved in phosphopeptide recognition.

• KIF1A transports organelles along axonal microtubules.
  
• KIF1C and KIF2 are plus-ended directed microtubule motors.
  
• KIF2C, KIF22 and KIF3B are plus-ended directed microtubule motors in mitotic cells
  
• KIF13B transports VEGFR2 from the Golgi to the endothelial cell surface.
  
• KIF16B is plus-ended directed microtubule motor involved in endosome transport and receptor recycling.
  
• KIFC1 transports DNA molecules along cytoskeleton filaments.
  
• Kar3 is kinesin protein in yeast.
  
• Eg5 or KIF11 is a kinesin (See Kinesin-5) which participates in mitosis.
  
• NOD is a Drosophila chromosome-associated kinesin.

See also CAP-Gly domain.

Disease

Mutations in KIF5A are involved in hereditary spastic paraplegia^[2]. Mutation in KIF1B is the cause of Charcot-Marie-Tooth disease ^[3]. Mutations in KIF22 cause spondyloepimetaphyseal dysplasia^[4].

Structural highlights

. Residue . Arg216 pivots to enable release or the phosphate release. in the KIF 'closed-state' before the Mg-ADP release. Binding of β-tubulin to KIF releases the latch, enabling the KIF conformation change and detaching KIF from the microtubule and enabling the next movement cycle^[5]. Water molecules shown as red spheres.

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