7月14日，细胞生物学组进行题为“Photoreceptor discs form through peripherindependent suppression of ciliary ectosome release”的journal club。
The primary cilium is a highly conserved organelle housing specialized molecules responsible for receiving and processing extracellular signals. A recently discovered property shared across many cilia is the ability to release small vesicles called ectosomes, which are used for exchanging protein and genetic material among cells. In this study, we report a novel role for ciliary ectosomes in building the elaborate photoreceptor outer segment flled with hundreds of tightly packed “disc” membranes. We demonstrate that the photoreceptor cilium has an innate ability to release massive amounts of ectosomes. However, this process is suppressed by the disc-specifc protein peripherin, which enables retained ectosomes to be morphed into discs. This new function of peripherin is performed independently from its wellestablished role in maintaining the high curvature of disc edges, and each function is fulflled by a separate part of peripherin’s molecule. Our fndings explain how the outer segment structure evolved from the primary cilium to provide photoreceptor cells with vast membrane surfaces for effcient light capture.
Schematic illustration of photoreceptor cilium development with and without peripherin.