Structural and dynamic analysis of intracellular ciliary protein trafficking

• Applicant: Dr. Lara Melanie Hoepfner
• Subject Area: Structural Biology ; Cell Biology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576083464

Cilia are evolutionarily conserved microtubule-based protrusions functioning as cellular antennae and/or motility generators with essential functions across diverse tissue types. The generation of cilia requires coordinated transport and delivery of ciliary proteins from their intracellular point of generation to the ciliary base. On their way ciliary membrane proteins and matrix proteins are sorted at the trans-Golgi network into coated ciliary-destined vesicles that travel to the periciliary compartment. While significant progress has been made in recent years, key challenges remain in fully elucidating the molecular mechanisms, participants and structural arrangement along the surface of intracellular vesicles that regulate and enable ciliary biogenesis. The proposed project aims to investigate the dynamic transport machinery, composition and structural arrangement of cilia-destined intracellular vesicles in the ciliated microalgae Chlamydomonas reinhardtii, which serves as an ideal model organism due to its synchronized deciliation/regeneration cycle and structural similarity to human cilia. The proposed work comprises three major objectives. First, tracking the spatiotemporal dynamics of marker protein FMG1, the major ciliary membrane protein in C. reinhardtii, from Golgi to cilium during regeneration to identify critical transition points and rate-limiting steps. Second, characterising transient intracellular interactors of FMG1 and co-transported ciliary proteins during cilia regeneration to create a comprehensive interaction map revealing how cells coordinate delivery of ciliary building blocks. Finally, determining the detailed structural architecture of ciliary transport vesicles, examining cargo organisation, intracellular interactions, and structural transformations during trafficking. Understanding the processes of cilia protein delivery is crucial, as defects in ciliogenesis are central to the development of ciliopathies. This work may identify key molecular players and interaction sites required for the accurate targeting and delivery of ciliary proteins, which could guide therapeutic strategies for treating ciliogenesis related genetic disorders on a future perspective.

• DFG Programme: WBP Fellowship
• International Connection: Italy
• Host: Dr. Gaia Pigino