title: Pen-2 is dispensable for endoproteolysis of presenilin 1, and nicastrin-Aph subcomplex is important for both γ-secretase assembly and substrate recruitment.
abstract: γ-secretase is a protease complex with at least four components: presenilin, nicastrin (NCT), anterior pharynx-defective 1 (Aph-1), and presenilin enhancer 2 (Pen-2). In this study, using knockout cell lines and small interfering RNA technology, our data demonstrated that the disappeared presenilin 1 C-terminal fragment (PS1C) caused by knockdown of pen-2 or knockout of NCT or Aph-1 was recovered by the addition of proteasome inhibitors, indicating that Pen-2, as well as NCT and Aph-1α, is dispensable for presenilin endoproteolysis. Our data also demonstrate that the formation of the nicastrin-Aph-1 subcomplex plays not only an important role in γ-secretase complex assembly but also in recruiting substrate C-terminal fragment of amyloid precursor protein generated by β-cleavage. Ablating any one component resulted in the instability of other components of the γ-secretase complex, and the presence of all three of the other components is required for full maturation of NCT.
authors.affiliation: Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.
authors.forename: Guozhang
authors.initials: G
authors.lastname: Mao
authors.forename: Mei-Zhen
authors.initials: MZ
authors.lastname: Cui
authors.forename: Tong
authors.initials: T
authors.lastname: Li
authors.forename: Yipeng
authors.initials: Y
authors.lastname: Jin
authors.forename: Xuemin
authors.initials: X
authors.lastname: Xu
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D010450:Endopeptidases / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D055786:Gene Knockout Techniques; D047468:Immunoprecipitation; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D053764:Presenilin-1 / Q000378:metabolism*; D059748:Proteolysis; D034741:RNA, Small Interfering
chemical_list: D008562:Membrane Glycoproteins; D053764:Presenilin-1; D034741:RNA, Small Interfering; C413604:nicastrin protein; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; C555827:presenilin enhancer 2, mouse