DESCRIPTION (provided by applicant): The photoreceptor outer segment is an elaborate primary cilium. The delivery of opsin into and along the cilium is critical for photoreceptor cell function and viability. The overall goal of this study is to understand the cellular mechanisms involved in these delivery processes. A combination of cell biological methods, including imaging of protein movements in the cilium of live mouse photoreceptor cells, will be used. Studies will address questions about opsin entry into and transport along the cilium, and the membrane diffusion barrier of the photoreceptor cilium. The proposed research incorporates technical innovation, including the measurements of real-time movements of opsin along the cilium, using a ciliated epithelial cell line and mouse rod photoreceptor cells. It will test novel concepts of opsin trafficking and the organization of the photoreceptor cilium.

PUBLIC HEALTH RELEVANCE: The proposed research will provide a fundamental mechanistic understanding of cellular processes in the photoreceptor cilium. It will provide insight into the pathogenesis of a wide range of diseases, known as ciliopathies, which include retinal degeneration. There will also be tangible benefits to preclinical studies for retinal degeneration therapies, in that mutant phenotypes, which can be used to assess therapeutic efficacy, are likely to be identified by the research.