Project Summary The long-term goal of our research program is to utilize new techniques and paradigms to understand the molecular determinants of physiological and disease-relevant phenomena associated with intrinsically disordered proteins (IDPs), or proteins that do not fold into stable structures in solution. Our focus is the self- association of IDPs that occur on high-affinity surfaces (such as microtubules or organelle membranes). Surfaces can promote self-association by increasing the local IDP concentration and templating IDP conformations more susceptible to self-association. However, both IDPs and their respective high-affinity surfaces are subject to numerous cellular modifications, dramatically expanding the experimental parameter space necessary to precisely characterize this phenomenon. Understanding how self-association is controlled in this space could be central to understanding their function in physiology and disease. Thus, our laboratory will adapt novel tools beyond traditional molecular biology to recreate conditions in two model systems where this phenomenon occurs: Tau condensation on microtubules and α-synuclein multimerization on synaptic vesicle membranes. Not only does the PI have extensive expertise with biophysically characterizing these IDPs, but the importance of Tau and α-synuclein to neurobiology and neurodegenerative disease provide a rich history of experimental insights that can be applied towards this phenomenon. Combined, this expertise and background can be incorporated into the phenomenon of surface-templated self-association of these IDPs. Furthermore, we will establish protocols/methods that can be easily exported to study other IDPs that undergo surface-templated self- association, as well. Overall, our intention by precisely understanding phenomena associated with select IDPs is to create generalizable mechanisms by which other IDPs behave, eventually providing a rigorous framework that has explanatory and predictive power for these proteins. By undertaking the proposed research, we hope to transition our purely biophysics laboratory to an entirely multidisciplinary program that connects protein behavior to cellular phenomenon.

Project Narrative Many intrinsically disordered proteins (or proteins that do not fold into stable structures) can self-associate on biological surfaces, but understanding control of this phenomenon as a function of protein and surface modifications remains experimentally intractable. Herein, we propose to apply novel tools to understand how modifications control this phenomenon in specific model systems, with an explicit focus on modifications that occur in physiology and disease. This program will benefit the scientific community by introducing novel techniques and the public health by elucidating the biophysical behavior of proteins critical to neuronal function.