Krzysztof Palczewski and his research team at the University of California Irvine revealed key structural determinants of rod photoreceptors--one of two major types of light-sensing cells in the retina. Using an imaging technique called cryo-electron tomography (Cryo-ET), the scientists visualized structures that enable precise spacing of discs in the rod outer segments (ROS). These discs, which are often depicted in illustrations as a stack of coins, reside inside the rods and bear the light-sensing receptor rhodopsin.
“Cryo-ET enabled us to image rim disc structures and to quantitatively assess the connectors between disks revealing the molecular landscape in ROS, including connectors between ROS disk membranes,” said Palczewski. “With this information, we are able to address open questions regarding the close disk stacking and the high membrane curvature at disk rims, which are specialized and essential structural characteristics of ROS.”
“This study gives us insight into how the viability of the retina is compromised by diseases, like retinitis pigmentosa and Stargardt disease, that affect structural proteins including peripherin of ABCA4. Armed with this data, we can now target new therapeutic approaches aimed at treating or potentially curing blindness," he said.