Membrane traffic between organelles is essential for secretion, uptake of nutrients, and the regulation of signal transduction. At the centre of this system lies the Golgi apparatus - the major sorting station that directs traffic from the endoplasmic reticulum (ER) to the rest of the cell and links the secretory and endocytic pathways.
The Golgi consists of a stack of flat compartments or “cisternae” arranged from cis to trans. Newly made proteins and glycolipids are delivered from the ER to the cisternae at the cis Golgi and pass through the stack to exit from the trans Golgi. Within the different cisternae are resident glycosylation enzymes that modify these proteins and glycolipids. Our lab investigates how the Golgi maintains its population of resident enzymes whilst their substrates move through and leave. Golgi resident proteins are known to continuously recycle within the stack in COPI-coated transport vesicles. The Golgi residents appear to be sorted into these vesicles by recognition of signals in either their cytoplasmic tails or their.
The PhD project is to investigate the mechanisms by which different sets of Golgi enzymes are sorted into vesicles in different parts of the stack. CRISPR-Cas9 gene deletion will be used to test the contribution of different factors to retention including the protein GOLPH3, the enigmatic TM9SF family, and other highly conserved Golgi proteins of unknown function. Proximity biotinylation (BioID) and proteomics will be used to search for further factors involved in retention. By this means we aim to develop a complete picture of the internal working of the Golgi stack.
The project will provide the opportunity to learn and apply a wide range of cell biological methods including CRISPR-Cas9 genome engineering of mammalian cells, advanced light microscopy, BioID and proteomics.
References
Welch, L.G., Peak-Chew, S., Begum, F., Stevens, T.J., Munro, S. (2021)
GOLPH3 and GOLPH3L are broad-spectrum COPI adaptors for sorting into intra-Golgi transport vesicles
J Cell Biol 220(10): e202106115
Welch, L.G., Munro, S. (2019)
A tale of short tails, through thick and thin: investigating the sorting mechanisms of Golgi enzymes
FEBS Lett 593(17): 2452-2465
Muschalik, N., Munro, S. (2018)
Golgins
Curr Biol 28(8):