Abstract Sugars, in particular glucose, are not only a ubiquitous cellular fuel source in virtually all organisms, but also serve as critical metabolic intermediates in which activated glucose molecules are transported to the ER and Golgi and used for glycosylating proteins, lipids and other organic compounds as part of the biosynthetic-secretory pathway. To accomplish these diverse and localized functions, the body utilizes membrane transporters and channels to transfer glucose and its intermediates across the otherwise impermeable membrane lipid bilayer that surrounds all cells and organelles. Secondary active transporters are key mediators in this process. Alternatively, the Voltage Dependent Anion Channel funnels glucose intermediates into the mitochondria where they enter the TCA cycle for the production of ATP. In their essential function for physiology, these proteins are implicated in numerous diseases and are designated targets for pharmaceutical compounds. In the parent R35 entitled, “Deciphering molecular details of cellular sugar transport and their roles in disease” we aim to characterize the structure and function of several families of transporters involved in cellular sugar and metabolite transport. Specifically, we want to study the Sodium Glucose Cotransporter (SGLT), Nucleotide Sugar Transporters (NST) and Sialic Acid Transporter (SiaT) and the Voltage-Dependent Anion Channel (VDAC). Human SGLTs are well known targets for treating Type II diabetes, but the molecular details of inhibition and the functional differences between isoforms are not well understood. This is in large part due to the lack of structural information. NSTs import various activated sugar compounds into the Golgi and ER, whereas SiaT serves to import scavenged sialic acids from its host. Differences between eukaryotic and pathogen NSTs could be exploited for therapeutic purposes. However, this family of transporters is still largely uncharacterized. VDAC is the central mediator of metabolite exchange through the outer mitochondrial membrane. Despite this critical role, key aspects of its functional gating and substrate transport are not well understood. Again, we hope that resolving additional structures of VDAC will help to answer these remaining questions. For all structure determination projects we need to collect, store and process large amounts of data. Our structural biology approach is complemented by functional studies to obtain a complete picture of sugar transport at an atomic resolution. We need to assess the functionality of heterologously- expressed proteins during the early stages of project. After obtaining the structures, we plan to interogate them by inserting mutations at critical sites identified in the structures and screen small- molecules as potential inhibitors.