Crystal structure of intraflagellar transport protein 80 reveals a homo-dimer required for ciliogenesis.

ABSTRACT: Oligomeric assemblies of intraflagellar transport (IFT) particles build cilia through sequential recruitment and transport of ciliary cargo proteins within cilia. Here we present the 1.8 Å resolution crystal structure of the Chlamydomonas IFT-B protein IFT80, which reveals the architecture of two N-terminal ?-propellers followed by an ?-helical extension. The N-terminal ?-propeller tethers IFT80 to the IFT-B complex via IFT38 whereas the second ?-propeller and the C-terminal ?-helical extension result in IFT80 homo-dimerization. Using CRISPR/Cas to create biallelic Ift80 frameshift mutations in IMCD3 mouse cells, we demonstrate that IFT80 is absolutely required for ciliogenesis. Structural mapping and rescue experiments reveal that human disease-causing missense mutations do not cluster within IFT80 and form functional IFT particles. Unlike missense mutant forms of IFT80, deletion of the C-terminal dimerization domain prevented rescue of ciliogenesis. Taken together our results may provide a first insight into higher order IFT complex formation likely required for IFT train formation.

SUBMITTER: Taschner M 

PROVIDER: S-EPMC5931796 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature