Ciliary transport of opsin.

As part of the renewal of photoreceptor outer segment disk membranes, membrane proteins are transported along the region of the cilium, connecting the inner and outer segments. Genetics studies have indicated the role of motor proteins in this transport. Direct analysis of live cells is needed to increase our understanding of the transport mechanisms further. Here, we show that transfection of hTERT-RPE1 cells with constructs encoding RHO-EGFP, but not RHO-mCherry, results in the distribution of fluorescently-tagged opsin in the plasma membrane. When the cells have differentiated and possess cilia, a portion of the RHO-EGFP was observed along the cilia. Due to the remarkable conservation of ciliary protein function, this system of Rho-Egfp transfected hTERT-RPE1 cells provides a valid model with which to study the ciliary transport of opsin directly in live cells.