title: Reversal of axonal growth defects in an extraocular fibrosis model by engineering the kinesin-microtubule interface.
abstract: Mutations in human β3-tubulin (TUBB3) cause an ocular motility disorder termed congenital fibrosis of the extraocular muscles type 3 (CFEOM3). In CFEOM3, the oculomotor nervous system develops abnormally due to impaired axon guidance and maintenance; however, the underlying mechanism linking TUBB3 mutations to axonal growth defects remains unclear. Here, we investigate microtubule (MT)-based motility in vitro using MTs formed with recombinant TUBB3. We find that the disease-associated TUBB3 mutations R262H and R262A impair the motility and ATPase activity of the kinesin motor. Engineering a mutation in the L12 loop of kinesin surprisingly restores a normal level of motility and ATPase activity on MTs carrying the R262A mutation. Moreover, in a CFEOM3 mouse model expressing the same mutation, overexpressing the suppressor mutant kinesin restores axonal growth in vivo. Collectively, these findings establish the critical role of the TUBB3-R262 residue for mediating kinesin interaction, which in turn is required for normal axonal growth and brain development.
authors.affiliation: Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Itsushi
authors.initials: I
authors.lastname: Minoura
authors.affiliation: Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Takazaki
authors.affiliation: Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Ayukawa
authors.affiliation: Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.|Laboratory for Molecular Mechanisms of Thalamus Development, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Saruta
authors.affiliation: Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: You
authors.initials: Y
authors.lastname: Hachikubo
authors.affiliation: Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Uchimura
authors.affiliation: Laboratory for Neuronal Growth Mechanisms, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Hida
authors.affiliation: Laboratory for Neuronal Growth Mechanisms, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kamiguchi
authors.affiliation: Laboratory for Molecular Mechanisms of Thalamus Development, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Shimogori
authors.affiliation: Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Muto
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001369:Axons / Q000473:pathology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism; D005260:Female; D005355:Fibrosis / Q000378:metabolism; D007150:Immunohistochemistry; D016547:Kinesins / Q000378:metabolism*; D051379:Mice; D008870:Microtubules / Q000378:metabolism*; D009154:Mutation; D011247:Pregnancy
chemical_list: D000251:Adenosine Triphosphatases; D016547:Kinesins