Human CFEOM1 mutations attenuate KIF21A autoinhibition and cause oculomotor axon stalling.

Neuron
Authors
Keywords
Abstract

The ocular motility disorder "Congenital fibrosis of the extraocular muscles type 1" (CFEOM1) results from heterozygous mutations altering the motor and third coiled-coil stalk of the anterograde kinesin, KIF21A. We demonstrate that Kif21a knockin mice harboring the most common human mutation develop CFEOM. The developing axons of the oculomotor nerve's superior division stall in the proximal nerve; the growth cones enlarge, extend excessive filopodia, and assume random trajectories. Inferior division axons reach the orbit but branch ectopically. We establish a gain-of-function mechanism and find that human motor or stalk mutations attenuate Kif21a autoinhibition, providing in vivo evidence for mammalian kinesin autoregulation. We identify Map1b as a Kif21a-interacting protein and report that Map1b⁻/⁻ mice develop CFEOM. The interaction between Kif21a and Map1b is likely to play a critical role in the pathogenesis of CFEOM1 and highlights a selective vulnerability of the developing oculomotor nerve to perturbations of the axon cytoskeleton.

Year of Publication
2014
Journal
Neuron
Volume
82
Issue
2
Pages
334-49
Date Published
2014 Apr 16
ISSN
1097-4199
URL
DOI
10.1016/j.neuron.2014.02.038
PubMed ID
24656932
PubMed Central ID
PMC4002761
Links
Grant list
R01 EY013583 / EY / NEI NIH HHS / United States
P30 HD018655 / HD / NICHD NIH HHS / United States
Howard Hughes Medical Institute / United States
P30 CA06516 / CA / NCI NIH HHS / United States
P30 HD18655 / HD / NICHD NIH HHS / United States
P30 CA006516 / CA / NCI NIH HHS / United States