Abstract
Purpose :
Mutations in the Ceramide Kinase-Like (CERKL) gene are associated with severe retinal degeneration. Several different functions have been proposed for CERKL, including mRNA-binding, association with microtubules, autophagy and mitochondrial biology. However, despite these findings, the pathways by which it exerts these roles and the direct connection to retinal disease are not fully understood. The purpose of this work was to identify and characterize CERKL-binding proteins in the mammalian retina.
Methods :
CERKL protein-protein interactions were identified implementing the Ras Recruitment System (RRS), a cytoplasmic-based yeast two-hybrid system, on a bovine retina cDNA library. Identified interactions were confirmed by co-immunoprecipitation. Immunostaining was used to test for co-localization of CERKL and its putative interactors in the retina.
Results :
We identified an interaction of CERKL with fumarylacetoacetate hydrolase domain containing 1 (FAHD1), a mitochondrial enzyme that serves as a regulator of mitochondrial function and senescence. This interaction was confirmed by co-immunoprecipitation. Immunostaining demonstrated that in the mouse retina CERKL and FAHD1 both localize to the cytoplasm of retinal ganglion cells, and may co-localize in amacrine and photoreceptor cells as well. In addition to FAHD1, we identified tumor protein translationally-controlled 1 (TPT1) as another putative CERKL interactor. TPT1 is involved in multiple biological processes, including stress response and autophagy.
Conclusions :
We identified putative interactions between CERKL and two retinal proteins, FAHD1 and TPT1. Both proteins are promising CERKL-interactors, given recent findings on CERKL's involvement in autophagy and mitochondrial biology in the retina. These findings enhance our understanding of CERKL's role in the normal retina and the pathophysiology of CERKL-related retinal degeneration.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.