PhD project

Supervisors: Girish Ram Mali & Anthony Roberts

Motile cilia perform vital roles to maintain human health. Their motion is powered by macromolecular motors called axonemal dyneins. Large quantities of dynein motors need to be transported into cilia to generate their vital beating motion. Dyneins are thought to be transported by the Intraflagellar Transport (IFT) system which comprises 22 distinct proteins that form train-like polymers to shuttle proteins in and out of cilia. Recent structural studies have revealed the overall molecular architecture of IFT trains that enter cilia. However, the molecular basis by which ciliary dyneins, particularly the force generating outer dynein arms (ODAs), attach to IFT trains remains poorly resolved.

 ODA transport requires packaging and inhibition by DNAAF9 (Shulin). Our most recent study suggests that Shulin not only inhibits ODAs but may also aid their attachment to the IFT system. This PhD project aims to build on our ongoing studies to elucidate the molecular mechanism of ODA motor attachment to IFT trains. The project will use an integrative cellular and structural biology approach combining biochemical reconstitutions, single-particle EM, protein structure modeling using AlphaFold and ultrastructure expansion microscopy (U-ExM).

Keywords:

• Biochemistry, Cell Biology / Development, Genetics, Molecular Biology, Structural Biology

Publications:

1. Housseini, K. et al., DNAAF9 (Shulin) and ARL3 regulate the transport and activation of ciliary Outer Dynein Arms (ODAs). BioRxiv preprint 2024.08.15.608058 (2024). DOI:10.1101/2024.08.15.608058.
2. Lacey, S. E., Foster, H. E. & Pigino, G. The molecular structure of IFT-A and IFT-B in anterograde intraflagellar transport trains. Nat. Struct. Mol. Biol. 2023 305 30, 584–593 1025 (2023). DOI: 10.1038/s41594-022-00905-5
3. Hesketh, S. J., Mukhopadhyay, A. G. et al.,  IFT-A structure reveals carriages for membrane protein transport into cilia. Cell. 2022 Dec 22;185(26):4971-4985.e16. DOI: 10.1016/j.cell.2022.11.010
4. Mali, G. R., Lau, C. L., Abid Ali, F et al., Shulin packages axonemal outer dynein arms for ciliary targeting. Science. 2021 Feb 371 (6532), 910–916. DOI: 10.1126/science.abe0526