Congrats to Nafisa! A much overdue post announcing the successful dissertation defense and hooding of Dr. Nafisa Nuzhat. Nafisa defended her dissertation titled “CEP162 deficiency causes human retinal degeneration and reveals a dual role in ciliogenesis and neurogenesis” in September 2023. Nafisa’s PhD journey was a true detective story as she followed the data to understand how a human mutation in a distal-end centriolar protein could impact the light-sensing photoreceptor cells of the retina. Nafisa loves plants, traveling, coffee, board games, and photography (also producing beautiful microscopy images). Along with all the adventures she had in the lab, we also went on two memorable conference trips to Arizona and the south of Spain. She is a fabulous travel buddy and tour guide. She is now off to new adventures as a postdoc with Andrew Kodani at HudsonAlpha. We wish her luck and great success. Many thanks to her sister-in-law for capturing the moment of hooding live.
The Pearring lab has a new paper out in Nature Communications! Primary nonmotile
cilia function as key signaling organelles on many cells in the human
body. Unlike other membrane organelles that are isolated compartments within
the cell, the ciliary membrane is continuous with the plasma membrane, and yet it has a distinct composition. The transition zone at the base of the cilium contains numerous structural complexes and functions as a filter allowing ciliary membrane proteins
to enter and restricting non-resident membrane proteins. In our paper, we investigated how the tectonic complex, residing within the transition zone membrane, regulates the ciliary membrane composition of the outer segment in rod photoreceptors. We found that the loss of Tctn1 resulted in the accumulation of non-ciliary membrane proteins into the outer segment and progressive rod degeneration. We also found that loss of tectonic did not affect the localization or expression of many transition zone proteins, including active transport carriers, or the ultrastructural hallmarks of the transition zone, such as the ciliary necklace or Y-links. We also rescued the leaky transition zone by re-expressing tectonic in rod photoreceptors. Finally, our FRAP data suggests that the tectonic complex functions by impeding the passive diffusion of membrane proteins as they enter the cilium, which allows active transport carriers to sort these proteins to their final destinations.
Watch the stop-motion film we made to model how the transition zone acts as a critical sorting station that establishes the cilium as a signaling organelle.
Molly Thorson was awarded an NIH F32 NRSA Postdoctoral Fellowship. Congratulations Molly! The fellowship offers three years of support. She will be investigating factors that regulate the structural formation and maintenance of the rod outer segment as well as quantitatively tracking ongoing disc renewal in both healthy and disease settings.
