EFA6A regulates retinal function through the control of photoreceptor cell activity and structure.

The initial step in visual perception, i.e., the collection of light, is carried out by the outer segments of photoreceptor cells. These outer segments, specialized primary cilia, house the photopigments that absorb photons. Here, we report that EFA6A, an exchange factor for the small G protein Arf6, previously described as a regulator of early ciliogenesis by promoting distal appendage vesicle fusion, is essential for visual function. We demonstrate that EFA6A is present in various layers of the mouse retina, including the photoreceptors and the retinal pigment epithelium (RPE). Accordingly, depletion of EFA6A in the mouse retina leads to both morphological and functional defects in photoreceptors, resembling the phenotypes observed in retinal ciliopathies. We also show that EFA6A depletion in RPE cells severely impairs their phagocytic activity. Thus, our results point out a key role for EFA6A in the control of visual activity.