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Cover legend: Retinal Müller glia respond to depletion of internal calcium stores with a calcium wave. A clockwise sequence of images, acquired at 6–15 s intervals, depicts an intact Müller cell, a Müller cell body fragment and a photoreceptor cell body loaded with the ratiometric Ca2+ indicator dye Fura-2. Low intracellular calcium concentrations [Ca2+]i are shown as blue, whereas increases in [Ca2+]i are depicted in warmer hues (red = high). The top (12 o'clock) panel shows cells with stores depleted in Ca2+ -free saline. Activation of store-operated TRPC1 and Orai channels, induced by addition of 2 mM Ca2+ saline, initially elevates [Ca2+]i in the apical and endfoot processes of the radial glial cell from where Ca2+ propagates towards the cell body in the form of a slow transcellular wave, reaching peak [Ca2+]i at 51 s (6 o'clock). For more information, see the article by Molnár, Yarishkin et al. (pages 3184–3198).