The AP-1 clathrin adaptor facilitates cilium formation and functions with RAB-8 in C. elegans ciliary membrane transport

J Cell Sci. 2010 Nov 15;123(Pt 22):3966-77. doi: 10.1242/jcs.073908. Epub 2010 Oct 27.


Clathrin adaptor (AP) complexes facilitate membrane trafficking between subcellular compartments. One such compartment is the cilium, whose dysfunction underlies disorders classified as ciliopathies. Although AP-1mu subunit (UNC-101) is linked to cilium formation and targeting of transmembrane proteins (ODR-10) to nematode sensory cilia at distal dendrite tips, these functions remain poorly understood. Here, using Caenorhabditis elegans sensory neurons and mammalian cell culture models, we find conservation of AP-1 function in facilitating cilium morphology, positioning and orientation, and microtubule stability and acetylation. These defects appear to be independent of IFT, because AP-1-depleted cells possess normal IFT protein localisation and motility. By contrast, disruption of chc-1 (clathrin) or rab-8 phenocopies unc-101 worms, preventing ODR-10 vesicle formation and causing misrouting of ODR-10 to all plasma membrane destinations. Finally, ODR-10 colocalises with RAB-8 in cell soma and they cotranslocate along dendrites, whereas ODR-10 and UNC-101 signals do not overlap. Together, these data implicate conserved roles for metazoan AP-1 in facilitating cilium structure and function, and suggest cooperation with RAB-8 to coordinate distinct early steps in neuronal ciliary membrane sorting and trafficking.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Protein Complex 1 / metabolism
  • Adaptor Protein Complex 1 / physiology*
  • Animals
  • Biological Transport
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans / physiology*
  • Cell Membrane / metabolism
  • Cilia / metabolism
  • Cilia / ultrastructure
  • Clathrin / metabolism


  • Adaptor Protein Complex 1
  • Clathrin