Super-resolution microscopy reveals majorly mono- and dimeric presenilin1/γ-secretase at the cell surface

• Published in: eLife Vol. 9
• Main Authors: Escamilla-Ayala, Abril Angélica, Sannerud, Ragna, Mondin, Magali, Poersch, Karin, Vermeire, Wendy, Paparelli, Laura, Berlage, Caroline, Koenig, Marcelle, Chavez-Gutierrez, Lucia, Ulbrich, Maximilian H, Munck, Sebastian, Mizuno, Hideaki, Annaert, Wim
• Format: Journal Article
• Language: English
• Published: England eLife Sciences Publications Ltd 07.07.2020; eLife Sciences Publications, Ltd
• Subjects: Alzheimer's disease; Amyloid precursor protein; Amyloid Precursor Protein Secretases - genetics; Amyloid Precursor Protein Secretases - metabolism; Animals; Cadherins; Cancer; Cell Biology; Cell Line; Cell Membrane - metabolism; Cell surface; Fibroblasts; gamma-secretase; Humans; Localization; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mice; Microscopy; Molecular weight; N-Cadherin; Neurodegenerative diseases; Nicastrin; Presenilin 1; Presenilin-1 - genetics; Presenilin-1 - metabolism; presenilin1; Proteins; Secretase; single-particle tracking; Stoichiometry; super-resolution microscopy; β-Site APP-cleaving enzyme 1; mouse; cell biology; single-particle tracking; gamma-secretase; Alzheimer's disease; human; presenilin1; super-resolution microscopy
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.56679

γ-Secretase is a multi-subunit enzyme whose aberrant activity is associated with Alzheimer's disease and cancer. While its structure is atomically resolved, γ-secretase localization in the membrane in situ relies mostly on biochemical data. Here, we combined fluorescent tagging of γ-secretase subunits with super-resolution microscopy in fibroblasts. Structured illumination microscopy revealed single γ-secretase complexes with a monodisperse distribution and in a 1:1 stoichiometry of PSEN1 and nicastrin subunits. In living cells, sptPALM revealed PSEN1/γ-secretase mainly with directed motility and frequenting 'hotspots' or high track-density areas that are sensitive to γ-secretase inhibitors. We visualized γ-secretase association with substrates like amyloid precursor protein and N-cadherin, but not with its sheddases ADAM10 or BACE1 at the cell surface, arguing against pre-formed megadalton complexes. Nonetheless, in living cells PSEN1/γ-secretase transiently visits ADAM10 hotspots. Our results highlight the power of super-resolution microscopy for the study of γ-secretase distribution and dynamics in the membrane.