Lack of N-glycosylation increases amyloidogenic processing of the amyloid precursor protein.

The amyloid precursor protein (APP) is a ubiquitously expressed type 1 transmembrane protein mostly known for serving as a precursor to the amyloid-β peptide (Aβ), a culprit in Alzheimer disease (AD). However, APP also has important physiological functions by being implicated in, for instance, adhesion, signaling, neuronal development, and synaptic function. Human APP contains 2 N-glycosylation sites, at asparagine (N) 467 (N467) and N496.

Engineered Human Induced Pluripotent Cells Enable Genetic Code Expansion in Brain Organoids.

Human induced pluripotent stem cell (hiPSC) technology has revolutionized studies on human biology. A wide range of cell types and tissue models can be derived from hiPSCs to study complex human diseases. Here, we use PiggyBac-mediated transgenesis to engineer hiPSCs with an expanded genetic code.

Dual Bioorthogonal Labeling of the Amyloid-β Protein Precursor Facilitates Simultaneous Visualization of the Protein and Its Cleavage Products.

The amyloid-β protein precursor (AβPP) is critical in the pathophysiology of Alzheimer's disease (AD), since two-step proteolytic processing of AβPP generates the neurotoxic amyloid-β peptide (Aβ). We developed a dual fluorescence labeling system to study the exact subcellular location of γ-secretase cleavage of AβPP. The C-terminal tail of AβPP was fluorescently labeled using a SNAP-tag, while the Aβ region of AβPP was fluorescently tagged with a dye at a genetically-encoded noncanonical amino acid (ncAA).