Understanding Photoreceptor Trafficking Pathways to the Outer Segment

Photoceptors in the retina are among the body’s hardest working cells. They must detect light coming into the eye and stimulate a biochemical signal, which in turn triggers an electrical response that is transmitted to the brain, resulting in sight

Most of this happens in a highly specialized compartment of the photoreceptor called the outer segment.

The molecular components residing within the outer segment must be arranged just right for the signaling to succeed. The outer segment contains a number of light absorbing, connecting and structural components that work together to create the visual response to light. Because key components are made elsewhere in the photoreceptor cell, they must be properly transported to and organized within the outer segment.

Problems in delivering these molecules to the outer segment are associated with some of the most severe inherited retinal diseases, notably Retinitis Pigmentosa.

Cell and developmental biologist Jillian Pearring, Ph.D., has been awarded an R01 grant from the National Institutes of Health to find out more about the routes along which these components travel to the outer segment, and what can go wrong along the way.

“We know that once these molecules are produced, they are packaged into vesicles for their delivery to the outer segment,” Dr. Pearring explains. “And we’ve already identified two primary pathways along which they travel.”

The study will address key questions about the delivery pathways to the outer segment: Why do certain molecules choose one route over the other? If a route is altered or blocked, how will the cell respond?

“We hope that a better understanding of the intercellular transportation used to reach the outer segment will help guide the development of new treatments to care for patients with these blinding inherited diseases,” she says.