Interaction of WDR60 intermediate chain with TCTEX1D2 light chain of the dynein-2 complex is crucial for ciliary protein trafficking

Mol Biol Cell. 2018 Jul 1;29(13):1628-1639. doi: 10.1091/mbc.E18-03-0173. Epub 2018 May 9.

Abstract

The dynein-2 complex mediates trafficking of ciliary proteins by powering the intraflagellar transport (IFT) machinery containing IFT-A and IFT-B complexes. Although 11 subunits are known to constitute the dynein-2 complex, with several light-chain subunits shared by the dynein-1 complex, the overall architecture of the dynein-2 complex has not been fully clarified. Utilizing the visible immunoprecipitation assay, we demonstrated the interaction modes among the dynein-2 subunits, including previously undefined interactions, such as that between WDR60 and the TCTEX1D2-DYNLT1/DYNLT3 dimer. The dynein-2 complex can be divided into three subcomplexes, namely DYNC2H1-DYNC2LI1, WDR34-DYNLL1/DYNLL2-DYNLRB1/DYNLRB2, and WDR60-TCTEX1D2-DYNLT1/DYNLT3. We established cell lines lacking WDR60 or TCTEX1D2, both of which are dynein-2-specific subunits encoded by ciliopathy-causing genes, and found that both WDR60-knockout (KO) and TCTEX1D2-KO cells show defects in retrograde ciliary protein trafficking, with WDR60-KO cells demonstrating more severe defects probably due to failed assembly of the dynein-2 complex. The exogenous expression of a WDR60 mutant lacking TCTEX1D2 binding partially restored retrograde trafficking to a level comparable to that of TCTEX1D2-KO cells. Thus, our results demonstrated that WDR60 plays a major role and TCTEX1D2 plays an auxiliary role in the dynein-2 complex to mediate retrograde ciliary protein trafficking.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Amino Acid Sequence
  • Biological Assay
  • Cell Line
  • Cilia / metabolism*
  • Conserved Sequence
  • Cytoskeletal Proteins
  • Dyneins / metabolism*
  • Gene Knockdown Techniques
  • HEK293 Cells
  • Humans
  • Protein Binding
  • Protein Domains
  • Protein Multimerization
  • Protein Subunits / metabolism
  • Protein Transport

Substances

  • Adaptor Proteins, Signal Transducing
  • Cytoskeletal Proteins
  • Protein Subunits
  • TCTEX1D2 protein, human
  • WDR60 protein, human
  • Dyneins