Regulated Intramembrane Proteolysis of the p75 neurotrophin receptor by γ-secretase in the context of the lipid bilayer

Alzheimer’s disease (AD) is a common neurodegenerative disorder affecting approximately 10% of people aged 65 and up and 30-50% over 85. In pathological AD representations, a way to recognize early onset AD is the increased levels of pro-NGF in BFCNs that come from the downregulation of NGF with age. Pro-NGF has a higher affinity for p75NTR, which binds and participates in the pro-NGF-p75NTR-sortilin complex sequentially cleaved by α- and γ-secretase. Pro-NGF triggers apoptosis through the cleavage of the intracellular membrane by γ-secretase. Since γ-secretase physically cleaves off the intramembrane portion that promotes TNF- and Fas-dependent apoptotic signaling pathways, it has a crucial role in AD and must be better understood. This research aims to understand better and visualize γ-secretase and its actions, specifically with its interactions with the substrate p75NTR in the RIP process. To analyze γ-secretase function, the proteins must be produced and analyzed through the protein expression protocol. During protein production, DNA, cell concentrations, and optical density measurements were difficult to produce due to the incompetency of e. coli cells (DH5α), contamination of the Sf9 insect cell culture, and decreased viability of aged insect cells. We identified the problems and improved the conditions for future project development.