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

• Published in: Neurobiology of disease 2003-11, Vol.14 (2), p.194-204
• Main Authors: Baulac, Stephanie, LaVoie, Matthew J, Kimberly, W.Taylor, Strahle, Jennifer, Wolfe, Michael S, Selkoe, Dennis J, Xia, Weiming
• Format: Article
• Language: English
• Subjects: Alzheimer; Amyloid; Amyloid Precursor Protein Secretases; Animals; Aph1; Aspartic Acid Endopeptidases; CHO Cells; Cricetinae; Endopeptidases - biosynthesis; Endopeptidases - metabolism; Endopeptidases - physiology; Humans; Membrane Glycoproteins - biosynthesis; Membrane Glycoproteins - metabolism; Membrane Glycoproteins - physiology; Membrane Proteins - biosynthesis; Membrane Proteins - metabolism; Membrane Proteins - physiology; Nicastrin; Pen-2; Peptide Hydrolases; Presenilin; Presenilin-1; Secretase; trans-Golgi Network - chemistry; trans-Golgi Network - metabolism; trans-Golgi Network - physiology
• ISSN: 0969-9961; 1095-953X
• DOI: 10.1016/S0969-9961(03)00123-2

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.