Vps-9 domain ankyrin repeat protein (Varp) is a widely expressed multi- domain protein of 1050 amino acids that resides in the cytosol. Varp has been shown to be a Rab21 GEF, a Rab32/38 effector and also helps to regulate VAMP7 fusion activity. Varp has more recently been proposed to bind to the Golgi tether golginA4, the kinesin motor Kif5a and the retromer complex subunit Vps29. The retromer core complex, comprising Vps35, Vps26, and Vps29, utilises different SNX proteins to mediate both Endosome to Golgi traffic, and Endosome to Plasma membrane traffic. The interaction of Varp with Vps29 localises Varp to endosomal membranes. Varp has two ‘zinc knuckle’ sequences (residues 369- 460 and 692-746) that have been shown to bind zinc and it is these small sequences that mediate the interaction with Vps29. The Varp:Vps29 complex structure was determined by a combined X-Ray Crystallographic/NMR method. This thesis demonstrates that one zinc knuckle sequence of Varp is sufficient to form an interaction with Vps29, with an affinity in the micromolar range. Single point mutations in Vps29 are sufficient to affect the binding affinity of Varp. Additionally, as some reported functional interactions have not yet been localised to any particular region of Varp, the as- yet-unstudied N-terminal domain of Varp (residues 1-136) was investigated using a Yeast-2-Hybrid screening approach, to try to identify any interaction partners that bind in this region. Many potential interaction partners were discovered, however neither Kif5a nor golginA4 was detected binding in this region.