Membrane biophysics in the context of Gaucher and Parkinson’s diseases: Impaired glucocerebrosidase activity, the hallmark of Gaucher disease and a major risk factor for Parkinson disease, correlates with elevated levels in neuronal membranes of the lipids glucosylceramide and glucosylsphingosine and of the membrane-interacting protein α-synuclein. Dysregulation in both lipids and α-synuclein impacts several biophysical properties of plasma and intracellular membranes including lipid bilayer packing and fluidity, domain organization, surface potential, intrinsic curvature, and permeability. Understanding the link between the two diseases might open new directions to develop innovative therapeutic approaches targeting the membrane properties affected. To achieve this goal, characterization of pharmacologically and genetically engineered cellular models of the diseases by advanced fluorescence spectroscopy and imaging methodologies strengthened by a multiprobe approach will provide insight into the biophysical properties and dynamics of cellular membranes.