Membrane binding proteins are a group of proteins that adhere only temporarily to the biological membranes. The reversible attachment of these molecules to biological membranes make them ideal participants in the cell signaling regulation and many other important cellular events. Previous studies demonstrated that these proteins penetrate the peripheral regions of the lipid bilayer by a combination of hydrophobic, electrostatic, and other no-covalent interactions. By far, there have been few studies on the regulatory mechanisms between membrane binding proteins and biological membranes.
Here we reported our recent finding that Ca2+ can regulate T cell receptor (TCR) phosphorylation by modulating phospholipid electrostatic property [Nature, 2013], as well as some of our primary results on protein-membrane interactions of C2A domain of Granuphilin, which regulates the docking and fusion of insulin vesicles to plasma membranes. In these studies, we took the advantages of both solution NMR and a new membrane mimic system -- Nanodiscs. We expect that calcium will play similar regulating roles in many other fundamental biological processes.