CFEOM1-associated kinesin KIF21A is a cortical microtubule growth inhibitor

Dev Cell. 2013 Oct 28;27(2):145-160. doi: 10.1016/j.devcel.2013.09.010. Epub 2013 Oct 10.


Mechanisms controlling microtubule dynamics at the cell cortex play a crucial role in cell morphogenesis and neuronal development. Here, we identified kinesin-4 KIF21A as an inhibitor of microtubule growth at the cell cortex. In vitro, KIF21A suppresses microtubule growth and inhibits catastrophes. In cells, KIF21A restricts microtubule growth and participates in organizing microtubule arrays at the cell edge. KIF21A is recruited to the cortex by KANK1, which coclusters with liprin-α1/β1 and the components of the LL5β-containing cortical microtubule attachment complexes. Mutations in KIF21A have been linked to congenital fibrosis of the extraocular muscles type 1 (CFEOM1), a dominant disorder associated with neurodevelopmental defects. CFEOM1-associated mutations relieve autoinhibition of the KIF21A motor, and this results in enhanced KIF21A accumulation in axonal growth cones, aberrant axon morphology, and reduced responsiveness to inhibitory cues. Our study provides mechanistic insight into cortical microtubule regulation and suggests that altered microtubule dynamics contribute to CFEOM1 pathogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • COS Cells
  • Carrier Proteins / metabolism
  • Cell Line
  • Chlorocebus aethiops
  • Cytoskeletal Proteins
  • Eye Diseases, Hereditary / genetics
  • Eye Diseases, Hereditary / metabolism*
  • Fibrosis / metabolism*
  • Growth Inhibitors
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Kinesins / genetics
  • Kinesins / metabolism*
  • Microtubules / metabolism*
  • Morphogenesis
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neurons / cytology
  • Neurons / metabolism*
  • Ocular Motility Disorders / metabolism*
  • Ophthalmoplegia
  • RNA Interference
  • RNA, Small Interfering
  • Tumor Suppressor Proteins / metabolism


  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Cytoskeletal Proteins
  • Growth Inhibitors
  • KANK1 protein, human
  • KIF21A protein, human
  • Nerve Tissue Proteins
  • PHLDB2 protein, human
  • PPFIA1 protein, human
  • PPFIBP1 protein, human
  • RNA, Small Interfering
  • Tumor Suppressor Proteins
  • Kinesins

Supplementary concepts

  • Congenital Fibrosis of the Extraocular Muscles
  • Fibrosis of Extraocular Muscles, Congenital, 3B