Essential subunit of the gamma-secretase complex, an endoprotease complex that catalyzes the intramembrane cleavage of integral proteins such as Notch receptors and APP (beta-amyloid precursor protein). It probably represents a stabilizing cofactor for the presenilin homodimer that promotes the formation of a stable complex.
A major component of the amyloid plaque core in Alzheimer's disease (AD) is the 40-42-residue amyloid beta peptide (Abeta). Mutations linked to AD such as those in presenilins 1 (PS1) and 2 (PS2) invariably increase the longer Abeta42 species that forms neurotoxic oligomers. It is believed that PS1/2 constitute the catalytic subunit of the gamma-secretase responsible for the final step in Abeta biogenesis. Recent genetic studies have identified a number of additional genes encoding APH1a, APH1b, PEN2, and Nicastrin proteins, which are part of the gamma-secretase complex with PS1. Further, knockout studies using RNAi showed that these components are essential for gamma-secretase activity. However, the nature of gamma-secretase and how the aforementioned proteins regulate its activity are still incompletely understood. Here we present evidence that unlike PS1, overexpression of these proteins can increase the levels of Abeta, suggesting that these proteins are limiting for gamma-secretase activity. In addition, our studies also suggest that the presenilin partners regulate the relative levels of Abeta40 and Abeta42.
Erratum in:
Biochem Biophys Res Commun. 307(3), 756 (2003 Aug 1)
Presenilin (PS, PS1/PS2) complexes are known to be responsible for the intramembranous gamma-secretase cleavage of the beta-amyloid precursor protein and signaling receptor Notch. PS holoprotein undergoes endoproteolysis by an unknown enzymatic activity to generate NH(2)- and COOH-terminal fragments, a process that is required for the formation of the active and stable PS/-gamma-secretase complex. Biochemical and genetic studies have recently identified nicastrin, APH-1, and PEN-2 as essential cofactors that physically interact with PS1 and are necessary for the gamma-secretase activity. However, their precise function in regulating the PS complex and gamma-secretase activity remains unknown. Here, we demonstrate that endogenous PEN-2 preferentially interacts with PS1 holoprotein. Down-regulation of PEN-2 expression by small interfering RNA (siRNA) abolishes the endoproteolysis of PS1, whereas overexpression of PEN-2 promotes the production of PS1 fragments, indicating a critical role for PEN-2 in PS1 endoproteolysis. Interestingly, accumulation of full-length PS1 resulting from down-regulation of PEN-2 is alleviated by additional siRNA down-regulation of APH-1. Furthermore, overexpression of APH-1 facilitates PEN-2-mediated PS1 proteolysis, resulting in a significant increase in PS1 fragments. Our data reveal a direct role of PEN-2 in proteolytic cleavage of PS1 and a regulatory function of APH-1, in coordination with PEN-2, in the biogenesis of the PS1 complex.
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.
Interacting selectively and non-covalently with any protein or protein complex (a complex of two or more proteins that may include other nonprotein molecules).
Evidence
1:
Inferred from Physical InteractionUniProtKB
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.
The chemical reactions and pathways resulting in the breakdown of amyloid precursor protein (APP), the precursor of beta-amyloid, a glycoprotein associated with Alzheimer's disease.
Gamma-secretase is a member of an unusual class of proteases with intramembrane catalytic sites. This enzyme cleaves many type I membrane proteins, including the amyloid beta-protein (Abeta) precursor (APP) and the Notch receptor. Biochemical and genetic studies have identified four membrane proteins as components of gamma-secretase: heterodimeric presenilin (PS) composed of its N- and C-terminal fragments (PS-NTF/CTF), a mature glycosylated form of nicastrin (NCT), Aph-1, and Pen-2. Recent data from studies in Drosophila, mammalian, and yeast cells suggest that PS, NCT, Aph-1, and Pen-2 are necessary and sufficient to reconstitute gamma-secretase activity. However, many unresolved issues, in particular the possibility of other structural or regulatory components, would be resolved by actually purifying the enzyme. Here, we report a detailed, multistep purification procedure for active gamma-secretase and an initial characterization of the purified protease. Extensive mass spectrometry of the purified proteins strongly suggests that PS-NTF/CTF, mNCT, Aph-1, and Pen-2 are the components of active gamma-secretase. Using the purified gamma-secretase, we describe factors that modulate the production of specific Abeta species: (1) phosphatidylcholine and sphingomyelin dramatically improve activity without changing cleavage specificity within an APP substrate; (2) increasing CHAPSO concentrations from 0.1 to 0.25% yields a approximately 100% increase in Abeta42 production; (3) exposure of an APP-based recombinant substrate to 0.5% SDS modulates cleavage specificity from a disease-mimicking pattern (high Abeta42/43) to a physiological pattern (high Abeta40); and (4) sulindac sulfide directly and preferentially decreases Abeta42 cleavage within the purified complex. Taken together, our results define a procedure for purifying active gamma-secretase and suggest that the lipid-mediated conformation of both enzyme and substrate regulate the production of the potentially neurotoxic Abeta42 and Abeta43 peptides.
Evidence
2:
Inferred from Mutant PhenotypeUniProtKB
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.
Gamma-secretase is a member of an unusual class of proteases with intramembrane catalytic sites. This enzyme cleaves many type I membrane proteins, including the amyloid beta-protein (Abeta) precursor (APP) and the Notch receptor. Biochemical and genetic studies have identified four membrane proteins as components of gamma-secretase: heterodimeric presenilin (PS) composed of its N- and C-terminal fragments (PS-NTF/CTF), a mature glycosylated form of nicastrin (NCT), Aph-1, and Pen-2. Recent data from studies in Drosophila, mammalian, and yeast cells suggest that PS, NCT, Aph-1, and Pen-2 are necessary and sufficient to reconstitute gamma-secretase activity. However, many unresolved issues, in particular the possibility of other structural or regulatory components, would be resolved by actually purifying the enzyme. Here, we report a detailed, multistep purification procedure for active gamma-secretase and an initial characterization of the purified protease. Extensive mass spectrometry of the purified proteins strongly suggests that PS-NTF/CTF, mNCT, Aph-1, and Pen-2 are the components of active gamma-secretase. Using the purified gamma-secretase, we describe factors that modulate the production of specific Abeta species: (1) phosphatidylcholine and sphingomyelin dramatically improve activity without changing cleavage specificity within an APP substrate; (2) increasing CHAPSO concentrations from 0.1 to 0.25% yields a approximately 100% increase in Abeta42 production; (3) exposure of an APP-based recombinant substrate to 0.5% SDS modulates cleavage specificity from a disease-mimicking pattern (high Abeta42/43) to a physiological pattern (high Abeta40); and (4) sulindac sulfide directly and preferentially decreases Abeta42 cleavage within the purified complex. Taken together, our results define a procedure for purifying active gamma-secretase and suggest that the lipid-mediated conformation of both enzyme and substrate regulate the production of the potentially neurotoxic Abeta42 and Abeta43 peptides.
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.
The process whose specific outcome is the progression of the metanephros over time, from its formation to the mature structure. In mammals, the metanephros is the excretory organ of the fetus, which develops into the mature kidney and is formed from the rear portion of the nephrogenic cord. The metanephros is an endocrine and metabolic organ that filters the blood and excretes the end products of body metabolism in the form of urine.
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.
Gamma-secretase is a member of an unusual class of proteases with intramembrane catalytic sites. This enzyme cleaves many type I membrane proteins, including the amyloid beta-protein (Abeta) precursor (APP) and the Notch receptor. Biochemical and genetic studies have identified four membrane proteins as components of gamma-secretase: heterodimeric presenilin (PS) composed of its N- and C-terminal fragments (PS-NTF/CTF), a mature glycosylated form of nicastrin (NCT), Aph-1, and Pen-2. Recent data from studies in Drosophila, mammalian, and yeast cells suggest that PS, NCT, Aph-1, and Pen-2 are necessary and sufficient to reconstitute gamma-secretase activity. However, many unresolved issues, in particular the possibility of other structural or regulatory components, would be resolved by actually purifying the enzyme. Here, we report a detailed, multistep purification procedure for active gamma-secretase and an initial characterization of the purified protease. Extensive mass spectrometry of the purified proteins strongly suggests that PS-NTF/CTF, mNCT, Aph-1, and Pen-2 are the components of active gamma-secretase. Using the purified gamma-secretase, we describe factors that modulate the production of specific Abeta species: (1) phosphatidylcholine and sphingomyelin dramatically improve activity without changing cleavage specificity within an APP substrate; (2) increasing CHAPSO concentrations from 0.1 to 0.25% yields a approximately 100% increase in Abeta42 production; (3) exposure of an APP-based recombinant substrate to 0.5% SDS modulates cleavage specificity from a disease-mimicking pattern (high Abeta42/43) to a physiological pattern (high Abeta40); and (4) sulindac sulfide directly and preferentially decreases Abeta42 cleavage within the purified complex. Taken together, our results define a procedure for purifying active gamma-secretase and suggest that the lipid-mediated conformation of both enzyme and substrate regulate the production of the potentially neurotoxic Abeta42 and Abeta43 peptides.
Gamma-secretase is a member of an unusual class of proteases with intramembrane catalytic sites. This enzyme cleaves many type I membrane proteins, including the amyloid beta-protein (Abeta) precursor (APP) and the Notch receptor. Biochemical and genetic studies have identified four membrane proteins as components of gamma-secretase: heterodimeric presenilin (PS) composed of its N- and C-terminal fragments (PS-NTF/CTF), a mature glycosylated form of nicastrin (NCT), Aph-1, and Pen-2. Recent data from studies in Drosophila, mammalian, and yeast cells suggest that PS, NCT, Aph-1, and Pen-2 are necessary and sufficient to reconstitute gamma-secretase activity. However, many unresolved issues, in particular the possibility of other structural or regulatory components, would be resolved by actually purifying the enzyme. Here, we report a detailed, multistep purification procedure for active gamma-secretase and an initial characterization of the purified protease. Extensive mass spectrometry of the purified proteins strongly suggests that PS-NTF/CTF, mNCT, Aph-1, and Pen-2 are the components of active gamma-secretase. Using the purified gamma-secretase, we describe factors that modulate the production of specific Abeta species: (1) phosphatidylcholine and sphingomyelin dramatically improve activity without changing cleavage specificity within an APP substrate; (2) increasing CHAPSO concentrations from 0.1 to 0.25% yields a approximately 100% increase in Abeta42 production; (3) exposure of an APP-based recombinant substrate to 0.5% SDS modulates cleavage specificity from a disease-mimicking pattern (high Abeta42/43) to a physiological pattern (high Abeta40); and (4) sulindac sulfide directly and preferentially decreases Abeta42 cleavage within the purified complex. Taken together, our results define a procedure for purifying active gamma-secretase and suggest that the lipid-mediated conformation of both enzyme and substrate regulate the production of the potentially neurotoxic Abeta42 and Abeta43 peptides.
Any protein maturation process achieved by the cleavage of a peptide bond or bonds within a protein. Protein maturation is the process leading to the attainment of the full functional capacity of a protein.
Gamma-secretase is a member of an unusual class of proteases with intramembrane catalytic sites. This enzyme cleaves many type I membrane proteins, including the amyloid beta-protein (Abeta) precursor (APP) and the Notch receptor. Biochemical and genetic studies have identified four membrane proteins as components of gamma-secretase: heterodimeric presenilin (PS) composed of its N- and C-terminal fragments (PS-NTF/CTF), a mature glycosylated form of nicastrin (NCT), Aph-1, and Pen-2. Recent data from studies in Drosophila, mammalian, and yeast cells suggest that PS, NCT, Aph-1, and Pen-2 are necessary and sufficient to reconstitute gamma-secretase activity. However, many unresolved issues, in particular the possibility of other structural or regulatory components, would be resolved by actually purifying the enzyme. Here, we report a detailed, multistep purification procedure for active gamma-secretase and an initial characterization of the purified protease. Extensive mass spectrometry of the purified proteins strongly suggests that PS-NTF/CTF, mNCT, Aph-1, and Pen-2 are the components of active gamma-secretase. Using the purified gamma-secretase, we describe factors that modulate the production of specific Abeta species: (1) phosphatidylcholine and sphingomyelin dramatically improve activity without changing cleavage specificity within an APP substrate; (2) increasing CHAPSO concentrations from 0.1 to 0.25% yields a approximately 100% increase in Abeta42 production; (3) exposure of an APP-based recombinant substrate to 0.5% SDS modulates cleavage specificity from a disease-mimicking pattern (high Abeta42/43) to a physiological pattern (high Abeta40); and (4) sulindac sulfide directly and preferentially decreases Abeta42 cleavage within the purified complex. Taken together, our results define a procedure for purifying active gamma-secretase and suggest that the lipid-mediated conformation of both enzyme and substrate regulate the production of the potentially neurotoxic Abeta42 and Abeta43 peptides.
Protein involved in the Notch signaling, a signaling pathway involved in cell-cell communications that regulates a broad spectrum of cell- fate determinations. Notch proteins are transmembrane receptors, which are cleaved by the gamma-secretase complex upon activation and released from the cell membrane and turn into transcriptional activators after their association with SU(H) proteins.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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