Functional γ-secretase complex assembly in Golgi/trans-Golgi network: interactions among presenilin, nicastrin, Aph1, Pen-2, and γ-secretase substrates

• Main Authors: Stephanie Baulac, Matthew J LaVoie, W.Taylor Kimberly, Jennifer Strahle, Michael S Wolfe, Dennis J Selkoe, Weiming Xia
• Format: Article
• Language: English
• Published: Elsevier 2003-11-01
• Series: Neurobiology of Disease
• Subjects: Alzheimer; Presenilin; Amyloid; Secretase; Aph1; Pen-2
• Online Access: http://www.sciencedirect.com/science/article/pii/S0969996103001232

γ-Secretase is a proteolytic complex whose substrates include Notch, β-amyloid precursor protein (APP), and several other type I transmembrane proteins. Presenilin (PS) and nicastrin are known components of this high-molecular-weight complex, and recent genetic screens in invertebrates have identified two additional gene products, Aph1 and Pen-2, as key factors in γ-secretase activity. Here, we examined the interaction of the components of the γ-secretase complex in Chinese hamster ovary cells stably expressing human forms of APP, PS1, Aph1, and Pen-2. Subcellular fractionation of membrane vesicles and subsequent coimmunoprecipitation of individual γ-secretase components revealed that interactions among all proteins occurred in the Golgi/trans-Golgi network (TGN) compartments. Furthermore, incubation of the Golgi/TGN-enriched vesicles resulted in de novo generation of amyloid β-protein and APP intracellular domain. Immunofluorescent staining of the individual γ-secretase components supported our biochemical evidence that the γ-secretase components assemble into the proteolytically active γ-secretase complex in the Golgi/TGN compartment.