Structural and functional characterisation of zDHHC S-Acyltransferases and their complexes with nanobodies, auxilliary proteins, co-factors and substrates

Protein S-acylation, commonly known as S-palmitoylation, is a reversible lipid post-translational modification (PTM) catalysed by a family of 23 DHHC domain- containing proteins. This modification regulates protein stability, activity, membrane association, and localisation. Palmitoylation targets many important proteins, including G proteins, ion channels, membrane receptors, and signalling proteins. Consequently, its dysregulation has been linked to cancers, as well as cardiovascular and neurological disorders. Although most zDHHC enzymes function autonomously, a subset has been found to interact with accessory proteins to cause activation, although their precise regulatory roles remain unclear. Furthermore, no full-length enzyme–substrate complexes has yet been structurally characterised, limiting our understanding of how substrate specificity and recognition is achieved by zDHHC enzymes. I aim to unravel the molecular mechanisms by which accessory proteins regulate zDHHC function and to decipher how zDHHC enzymes recognise and interact with their diverse substrates, using structural biology approaches. I will combine biochemical and structural analyses, including specialised electron microscopy techniques, to: • Determine the architecture of human zDHHCs and their complexes with accessory proteins and substrates • Elucidate mechanisms of substrate recognition and specificity by zDHHCs This work could provide the molecular basis for exploiting S-acylation as a future drug target with industrial, clinical, and societal impact.