Modulation of ion channels by lipids and protein folding helper enzymes - Project Summary/Abstract (30 lines) Transient Receptor Potential (TRP) channels are ubiquitously expressed across the human body where they serve critical roles in sensing a range of external and internal stimuli. In addition to their well- established contributions to acute and chronic pain, TRP channels also have been associated with kidney disease, neurodegeneration, diabetes, and cardiovascular disorders, among others. Developing detailed models of TRP channel function and regulation under physiological conditions therefore is essential to defining their roles in health and disease. TRP channels respond to a variety of stimuli and interact with many regulatory molecules in cells. Despite significant advances in understanding the structure, function, and small-molecule modulation of these channels, less information is available about how the general cellular environment influences and controls TRP channels. Like many other ion channels, TRP channels consist of transmembrane domains as well as cytosolic domains, which means that different parts of the same protein are exposed to very different environments. This also means that the pool of potential interaction partners can be divided into two categories: membrane-delimited interaction partners such as lipids, and cytosolic interaction partners such as proteins. Our goal is to systematically dissect the contributions of each environment to the polymodal regulation of TRP channels. To identify physiologically relevant factors that modulate TRP channel activity, we will perform cell-based experiments tailored to each of the two environments. We will then reconstitute TRP channels together with these factors from purified components in vitro for detailed structure-function correlations. In contrast to the complex cellular environment, this approach will allow us to establish tightly controlled and exactly defined experimental conditions, which is necessary to develop quantitative models of TRP channel regulation by other cellular components. Our interdisciplinary approach will combine molecular biology, cellular imaging, biophysical and functional studies of purified proteins, and structural biology under conditions closely mimicking physiological environments. With our work, we will contribute to a more integrative understanding of TRP channel physiology, which may serve as a framework for the development of novel pharmaceuticals.
