Quantitative Proteomics Identifies Potential Molecular Adaptations in Mouse Models of Congenital Stationary Night Blindness Type 2.

Pathogenic variants in the CACNA1F gene are linked to congenital stationary night blindness type 2 though their specific molecular effects remain elusive. This study examines the retinal impact of two variants: a truncation (RX) and a gain-of-function (IT) to explore variant-specific retinal proteome changes. Electroretinography showed that RX primarily affects rod pathways, while IT disrupts both rod and cone signaling, consistent with morphological findings. Comprehensive quantitative proteomic analysis using mass spectrometry identified approximately 4000 proteins across wild-type control and mutant retinas, including also low-abundant membrane proteins. IT retinas exhibited widespread proteomic remodeling suggesting broad cellular responses and also compensatory molecular adaptations. In contrast, RX retinas displayed a more restricted profile. Similar to IT retinas, we found reduced Cav1.4 protein levels but without transcriptional downregulation in RX, alongside selective changes in synaptic proteins such as Erc1, Lrfn2, vGlut1, and Rab3a. These findings suggest selective molecular changes in synaptic organization and calcium-related pathways in RX retinas, offering insights into the mechanisms of Cav1.4 dysfunction in retinal disease. Deep proteomic analysis demonstrates how retinal cells reorganize their molecular architecture in response to calcium channel defects and highlights the utility of comprehensive proteomics to characterize adaptive cellular responses to genetic perturbations in retinal synaptic organization.