Mammalian APH-1 interacts with presenilin and nicastrin and is required for intramembrane proteolysis of amyloid-beta precursor protein and Notch.
Presenilin and nicastrin are essential components of the gamma-secretase complex that is required for the intramembrane proteolysis of an increasing number of membrane proteins including the amyloid-beta precursor protein (APP) and Notch. By using co-immunoprecipitation and nickel affinity pull-down approaches, we now show that mammalian APH-1 (mAPH-1), a conserved multipass membrane protein, physically associates with nicastrin and the heterodimers of the presenilin amino- and carboxyl-terminal fragments in human cell lines and in rat brain. Similar to the loss of presenilin or nicastrin, the inactivation of endogenous mAPH-1 using small interfering RNAs results in the decrease of presenilin levels, accumulation of gamma-secretase substrates (APP carboxyl-terminal fragments), and reduction of gamma-secretase products (amyloid-beta peptides and the intracellular domains of APP and Notch). These data indicate that mAPH-1 is probably a functional component of the gamma-secretase complex required for the intramembrane proteolysis of APP and Notch.
Lee
Sheu-Fen
SF
Center for Basic Neuroscience and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9111, USA.
Shah
Sanjiv
S
Li
Hongqiao
H
Yu
Cong
C
Han
Weiping
W
Yu
Gang
G
D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D019281:Dimerization; D010450:Endopeptidases / Q000378:metabolism; D017930:Genes, Reporter; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D010447:Peptide Hydrolases; D053764:Presenilin-1; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015534:Trans-Activators / Q000378:metabolism*
D016564:Amyloid beta-Protein Precursor; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009841:Oligonucleotides; C508853:PSEN1 protein, human; D053764:Presenilin-1; D034741:RNA, Small Interfering; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; C413604:nicastrin protein; C475154:APH1A protein, human; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D010447:Peptide Hydrolases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human