How is membrane traffic organised in human cells?
Secondary Supervisor(s): Professor Corinne Smith
University of Registration: University of Warwick
BBSRC Strategic Research Priority: Understanding the Rules of Life (Structural Biology, Systems Biology)
Project Outline
Eukaryotic cells are compartmentalized: they contain organelles and membrane-bound domains that each have distinct identities. For example, the endoplasmic reticulum is different to the Golgi apparatus. The identities of these compartments must be maintained, yet there needs to be exchange of specific materials (proteins and lipids) between them. This exchange, via vesicle transport, is tightly regulated in order to maintain compartment identity. Proper cellular organisation is core to cells functioning normally and as such, membrane traffic controls most of the things that cells need to do: move, secrete, signal and so on.
Until recently it was thought that we had a complete inventory of the types of vesicles used in membrane traffic. There were several types of vesicular carrier described, including clathrin-coated vesicles (50–100 nm diameter) formed at the plasma membrane (PM) or TGN, COPII-coated vesicles (60–70 nm) originating at the ER, and intra-Golgi transport vesicles (70–90 nm). Our lab have recently found a new class of transport vesicle, termed intracellular nanovesicles (INVs). These small (30 nm diameter) vesicles are widespread in the membrane trafficking system and play a role in anterograde traffic, Golgi integrity and recycling of endocytosed material (Figure 1).
Due to their recent discovery, there is a lot to learn about these vesicles. We are actively pursuing many of the basic questions: how do they form? How are they transported? What cargos do they carry? From this we want to understand how membrane traffic is organised, and where these vesicles fit into the picture. We are using a combination of state-of-the-art imaging methods (super-resolution microscopy and electron microscopy), genetically encoded probes and proteomics. Due to their ubiquity and their recent discovery, understanding INVs in more detail is likely to have wide impact in the membrane trafficking field and on cell biology in general.
Further reading
Fesnko, M., Moore, D.J., Ewbank, P. & Royle, S.J. (2024) ATG9 vesicles are a subtype of intracellular nanovesicle. bioRxiv, doi: 10.1101/2024.09.12.612637
Sittewelle, M. & Royle, S.J. (2024) Passive diffusion accounts for the majority of intracellular nanovesicle transport. Life Sci Alliance. 7 (1) e202302406. doi: 10.26508/lsa.202302406
Larocque, G. & Royle, S.J. (2022) Integrating intracellular nanovesicles into integrin trafficking pathways and beyond. Cell. Mol. Life Sci., 79: 335. doi: 10.1083/jcb.201812044
Larocque, G., La-Borde, P.J., Clarke, N.I., Carter, N.J. & Royle, S.J. (2020) Tumor Protein D54 defines a new class of intracellular transport vesicles. J. Cell Biol., 219: e201812044. doi: 10.1083/jcb.201812044
Larocque, G., Moore, D.J., Sittewelle, M., Kuey, C., Hetmanski, J.H.R, La-Borde, P.J., Wilson, B.J., Clarke, N.I., Caswell, P.T. & Royle, S.J. (2021) Intracellular nanovesicles mediate α5β1 integrin trafficking during cell migration. J. Cell Biol. 220: e202009028. doi: 10.1083/jcb.202009028
Techniques
Cell biology: culturing cell lines, genetic manipulation using transfection, RNAi and CRISPR/Cas9.
Molecular biology: plasmid design and construction, DNA purification.
Microscopy: light microscopy and electron microscopy.
Data analysis: image analysis, segmentation, dealing with large datasets, programming using R, statistical modelling.
