Superresolution Pattern Recognition Reveals the Architectural Map of the Ciliary Transition Zone

Sci Rep. 2015 Sep 14;5:14096. doi: 10.1038/srep14096.

Abstract

The transition zone (TZ) of primary cilia serves as a diffusion barrier to regulate ciliogenesis and receptor localization for key signaling events such as sonic hedgehog signaling. Its gating mechanism is poorly understood due to the tiny volume accommodating a large number of ciliopathy-associated molecules. Here we performed stimulated emission depletion (STED) imaging of collective samples and recreated superresolved relative localizations of eight representative species of ciliary proteins using position averages and overlapped with representative electron microscopy (EM) images, defining an architectural foundation at the ciliary base. Upon this framework, transmembrane proteins TMEM67 and TCTN2 were accumulated at the same axial level as MKS1 and RPGRIP1L, suggesting that their regulation roles for tissue-specific ciliogenesis occur at a specific level of the TZ. CEP290 is surprisingly localized at a different axial level bridging the basal body (BB) and other TZ proteins. Upon this molecular architecture, two reservoirs of intraflagellar transport (IFT) particles, correlating with phases of ciliary growth, are present: one colocalized with the transition fibers (TFs) while the other situated beyond the distal edge of the TZ. Together, our results reveal an unprecedented structural framework of the TZ, facilitating our understanding in molecular screening and assembly at the ciliary base.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Antigens, Neoplasm / metabolism
  • Cell Cycle Proteins
  • Cell Line
  • Cilia / chemistry
  • Cilia / metabolism*
  • Cilia / ultrastructure
  • Cytoskeletal Proteins
  • Genes, Reporter
  • Humans
  • Membrane Proteins / metabolism
  • Microscopy, Confocal
  • Microscopy, Electron
  • Neoplasm Proteins / metabolism
  • Proteins / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Antigens, Neoplasm
  • Cell Cycle Proteins
  • Cep290 protein, human
  • Cytoskeletal Proteins
  • MKS1 protein, human
  • Membrane Proteins
  • Neoplasm Proteins
  • Proteins
  • RPGRIP1L protein, human
  • TCTN2 protein, human
  • TMEM67 protein, human