The polarized distribution of neuronal proteins to axons and dendrites relies on microtubule-binding proteins such as CRMP, directed motors such as the kinesin UNC-104 (Kif1A) and diffusion barriers such as ankyrin. The causative relationships among these molecules are unknown. We show here that Caenorhabditis elegans CRMP (UNC-33) acts early in neuronal development, together with ankyrin (UNC-44), to organize microtubule asymmetry and axon-dendrite sorting. In unc-33 and unc-44 mutants, axonal proteins were mislocalized to dendrites and vice versa, suggesting bidirectional failures of axon-dendrite identity. unc-44 directed UNC-33 localization to axons, where it was enriched in a region that resembled the axon initial segment. unc-33 and unc-44 were both required to establish the asymmetric dynamics of axonal and dendritic microtubules; in their absence, microtubules were disorganized, the axonal kinesin UNC-104 invaded dendrites, and inappropriate UNC-104 activity randomized axonal protein sorting. We suggest that UNC-44 and UNC-33 direct polarized sorting through their global effects on neuronal microtubule organization.
Pubmed ID: 22101643 RIS Download
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Caenorhabditis elegans with name odr-4(n2144) III. from WB.
View all literature mentionsCaenorhabditis elegans with name kyIs445[Pdes-2::mCherry::RAB-3; Pdes-2::SAD-1::GFP; Podr-1::DsRED];hrtEx23[Pdes-2::GFP::KBP; Pmyo-2::GFP] from WB.
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