Oligomeric Plasticity Gating Mechanisms in Ion Channels

ongoing

Ion channels are transmembrane proteins regulating ion flux across cell membranes and are crucial for numerous physiological processes. Hence, ion channels are implicated in many diseases. To further drug development targeting ion channels, a comprehensive understanding is needed not only of their low-energy abundant states, but also of their rare and transient high-energy states, which play critical roles in channel function, regulation, and folding. The cutting-edge high-speed atomic force microscopy (HS-AFM) technique allows now to study such states, by providing simultaneously, on a single-molecule level, both dynamic and structural information of freely diffusing ion channels in the membrane, a feat that is currently impossible with other methods. Recently, I discovered using HS-AFM that the TRPV3 channel possesses a rare and transient pentameric state that reversibly interconverts with its canonical tetrameric sate, potentially conferring it new function. Here, I aim to investigate further the functional role and biological relevance of this finding, while concomitantly investigating if similar oligomeric plasticity occurs in other ion channels of diverse functions. Most particularly, I aim to investigate whether reversible oligomeric changes could be an additional mechanism for ion channels to modulate function. To do so, I will: 1) Discover reversible oligomeric transitions in other ion channels. 2) Reveal how reversible oligomeric transitions could modulate function. 3) Assess the physiological relevance and feasibility of such transitions. Positive results will lead to a paradigm shift in the way we think about the assembly, dynamics, and function of ion channels and introduce a novel new concept of how ion channels undergo conformational changes. Additionally, results will be of high impact to translational applications such as drug development and drug delivery and establish HS-AFM as a powerful complementary method in the field of structural biology.