Research in the Rhoades lab aims to elucidate the principles that link protein conformational change with structure-function relationships, focusing on understanding structural plasticity in intrinsically disordered proteins (IDPs). IDPs do not form stable structures under physiological conditions; for many, function is dependent upon disorder. This is in striking contrast to the structure-function paradigm that dominates our understanding of globular proteins. Given the large fraction of the eukaryotic proteome predicted to be disordered, the scope of the problem and the need for new insights are enormous. Much of our effort is directed towards IDPs whose aggregation is central to the pathology of several degenerative diseases: α-synuclein (Parkinson’s disease), tau (Alzheimer’s disease), and IAPP (Type II Diabetes). These three proteins have diverse native functions and binding partners, but share intriguing commonalities of toxic mechanism and the importance of templated selfassembly. Studying systems in parallel allows us to generate protein and disease-specific insights as well as determine principles relevant to general functional and dysfunctional mechanisms of IDPs. Our primary approaches center on single molecule optical techniques. These approaches enable quantitative and structural assessments of our systems in isolation and in the context of biologically relevant interactions. Single molecule approaches are unique in their ability to characterize systems which exist and function as a dynamic ensemble of states.