Structure and Dynamics of Phosphatidylinositol Phosphates in Lipid Bilayers

Our lab studies membranes and membrane binding using NMR and molecular dynamics simulations with particular focus on the signaling lipids phosphatidylinositol phosphates (PIPs). We investigate PIPs in model lipid bilayers with 1H, 13C, and 31P-detected experiments acquired in solution and at static, 15, and 40 kHz MAS with the goal to fully characterize the PIPs in the lipid bilayer, under a variety of conditions. In this study we investigate the effects of Ca2+ and phosphatidylserine on the structure and dynamics of PIP3 in model bilayers. We show how measurements of relaxation and dipolar coupling-based experiments can be used to probe the structure and dynamics of PIPs. Our results show that even sub-stoichiometric amounts of Ca2+ restrict the motion of individual PIP phosphates and that at the larger concentrations present during signaling event the lateral diffusion of all lipids in the membrane are impacted.