Issues

Cover picture: Outer segments of three Xenopus rod photoreceptors expressing rhodopsin-EGFP imaged end-on by confocal microscopy reveal incisures in the disc membranes that segment them into signaling microcompartments (top). High resolution multiphoton photoconversion within individual microcompartments (indicated by red dots, middle) allowed direct quantification of the impact of signaling compartment geometry on the diffusion of the G protein–coupled receptor rhodopsin (bottom; see article by Najafi et al., 249–266).