A proteomic survey of microtubule-associated proteins in a R402H TUBA1A mutant mouse

PLoS Genet. 2020 Nov 2;16(11):e1009104. doi: 10.1371/journal.pgen.1009104. eCollection 2020 Nov.

Abstract

Microtubules play a critical role in multiple aspects of neurodevelopment, including the generation, migration and differentiation of neurons. A recurrent mutation (R402H) in the α-tubulin gene TUBA1A is known to cause lissencephaly with cerebellar and striatal phenotypes. Previous work has shown that this mutation does not perturb the chaperone-mediated folding of tubulin heterodimers, which are able to assemble and incorporate into the microtubule lattice. To explore the molecular mechanisms that cause the disease state we generated a new conditional mouse line that recapitulates the R402H variant. We show that heterozygous mutants present with laminar phenotypes in the cortex and hippocampus, as well as a reduction in striatal size and cerebellar abnormalities. We demonstrate that homozygous expression of the R402H allele causes neuronal death and exacerbates a cell intrinsic defect in cortical neuronal migration. Microtubule sedimentation assays coupled with quantitative mass spectrometry demonstrated that the binding and/or levels of multiple microtubule associated proteins (MAPs) are perturbed by the R402H mutation including VAPB, REEP1, EZRIN, PRNP and DYNC1l1/2. Consistent with these data we show that the R402H mutation impairs dynein-mediated transport which is associated with a decoupling of the nucleus to the microtubule organising center. Our data support a model whereby the R402H variant is able to fold and incorporate into microtubules, but acts as a gain of function by perturbing the binding of MAPs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / cytology
  • Brain / embryology
  • Brain / pathology*
  • Cell Movement
  • Cytoplasmic Dyneins / metabolism
  • Disease Models, Animal
  • Embryo, Mammalian
  • Female
  • Heterozygote
  • Humans
  • Lissencephaly / genetics
  • Lissencephaly / pathology*
  • Mice
  • Mice, Transgenic
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / metabolism
  • Mutation, Missense
  • Neurons / metabolism
  • Neurons / pathology
  • Protein Binding / genetics
  • Proteomics
  • Tubulin / genetics*
  • Tubulin / metabolism

Substances

  • Microtubule-Associated Proteins
  • Tuba1a protein, mouse
  • Tubulin
  • Cytoplasmic Dyneins

Grant support

D.A.K. is supported Austrian Science Fund (P29483, I 2681, https://www.fwf.ac.at). A.W.P. is a recipient of a DOC Fellowship of the Austrian Academy of Sciences (https://www.oeaw.ac.at/). T.D.C is a recipient of a Marie Skłodowska-Curie Actions Individual Fellowship (800247, https://ec.europa.eu/research/mariecurieactions/node_en). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.