Tag secretase [16 articles]

Abstract

10.1073/pnas.0910757106 γ-Secretase cleaves multiple substrates within the transmembrane domain that include the amyloid precursor protein as well as the Notch family of receptors. These substrates are associated with Alzheimer disease and cancer. Despite extensive investigation of this protease, little is known regarding the regulation of γ-secretase specificity. To discover selective inhibitors for drug development and for probing the mechanisms of γ-secretase specificity, we screened chemical libraries and consequently developed a di-coumarin family of inhibitors that preferentially inhibit γ-secretase-mediated production of Aβ42 ...

Abstract

ADAM10 is involved in the proteolytic processing and shedding of proteins such as the amyloid precursor protein (APP), cadherins, and the Notch receptors, thereby initiating the regulated intramembrane proteolysis (RIP) of these proteins. Here, we demonstrate that the sheddase ADAM10 is also subject to RIP. We identify ADAM9 and -15 as the proteases responsible for releasing the ADAM10 ectodomain, and Presenilin/gamma-Secretase as the protease responsible for the release of the ADAM10 intracellular domain (ICD). This domain then translocates to the nucleus ...

Abstract

Gamma-Secretase is a promiscuous protease that cleaves bitopic membrane proteins within the lipid bilayer. Elucidating both the mechanistic basis of gamma-secretase proteolysis and the precise factors regulating substrate identification is important because modulation of this biochemical degradative process can have important consequences in a physiological and pathophysiological context. Here, we briefly review such information for all major classes of intramembranously cleaving proteases (I-CLiPs), with an emphasis on gamma-secretase, an I-CLiP closely linked to the etiology of Alzheimer's disease. A large body ...

Abstract

gamma -Secretase mediates the final proteolytic cleavage, which liberates amyloid beta-peptide (Abeta), the major component of senile plaques in the brains of Alzheimer disease patients. Therefore, gamma-secretase is a prime target for Abeta-lowering therapeutic strategies. gamma-Secretase is a protein complex composed of four different subunits, presenilin (PS), APH-1, nicastrin, and PEN-2, which are most likely present in a 1:1:1:1 stoichiometry. PS harbors the catalytically active site, which is critically required for the aspartyl protease activity of gamma-secretase. Moreover, numerous familial Alzheimer ...

Abstract

ADAM metalloproteases play important roles in development and disease. One of the key functions of ADAMs is the proteolytic processing of Notch receptors and their ligands. ADAM-mediated cleavage of Notch represents the first step in regulated intramembrane proteolysis of the receptor, leading to activation of the Notch pathway. Recent reports indicate that the transmembrane Notch ligands also undergo ADAM-mediated processing in cultured cells and in vivo. The proteolytic processing of Notch ligands modulates the strength and duration of Notch signals, leads ...

Abstract

Physiological angiogenesis is essential for development, homeostasis and tissue repair but pathological neovascularization is a major feature of tumours, rheumatoid arthritis and ocular complications. Studies over the last decade have identified gamma-secretase, a presenilin-dependent protease, as a key regulator of angiogenesis through: (i) regulated intramembrane proteolysis and transmembrane cleavage of receptors (e.g. VEGFR-1, Notch, ErbB-4, IGFI-R) followed by translocation of the intracellular domain to the nucleus, (ii) translocation of full length membrane-bound receptors to the nucleus (VEGFR-1), (iii) phosphorylation of membrane ...

Abstract

Gradual changes in steady-state levels of beta amyloid peptides (Aβ) in brain are considered an initial step in the amyloid cascade hypothesis of Alzheimer’s disease. Aβ is a product of the secretase cleavage of amyloid precursor protein (APP). There is evidence that the membrane lipid environment may modulate secretase activity and alters its function. Cleavage of APP strongly depends on membrane properties. Since Aβ perturbs cell membrane fluidity, the cell membrane may be the location where the neurotoxic cascade of Aβ ...

Abstract

Notch signaling is a well-conserved pathway involved in cell fate decisions, proliferation and apoptosis. We report on the involvement of Notch signaling in regulating gene expression in activated macrophages. Toll-like receptors (TLR) agonists such as bacterial lipopeptide, polyI:C, lipopolysaccharide and unmethylated CpG DNA all induced up-regulation of Notch1 in primary and macrophage-like cell lines. Notch1 up-regulation was dependent on the MyD88 pathway when stimulated through TLR2, but not TLR4. Activated Notch1 and expression of the Notch target genes, Hes1 and Deltex, ...

Abstract

The amyloid- peptide (A) is the major protein component of the characteristic cerebral plaques of Alzheimer's disease (AD), and a large body of evidence supports a pathogenic role for this peptide. Thus, the proteases - and -secretase that are responsible for carving Ab out of its precursor protein are considered prime targets for therapeutic design. -Secretase is a membrane-anchored aspartyl protease of the pepsin family, while -secretase is much more complex. -Secretase requires presenilin, a multipass membrane protein that is the ...

Abstract

Amyloid plaques, which are composed of amyloid-[beta] peptide (A[beta]), signify Alzheimer's disease pathology. Secretases generate A[beta] by processing the [beta]-amyloid precursor protein. [gamma]-Secretase, a complex comprising four different proteins, liberates A[beta] from its precursor by intramembrane proteolysis. The first impression of the shape of [gamma]-secretase has recently been revealed by electron microscopy. It indicates a spherical transmembrane particle with an interior chamber that, presumably, accommodates its catalytic residues, and two openings that might be exit sites for the cleavage products. ...

Abstract

[gamma]-Secretase belongs to an atypical class of aspartic proteases that hydrolyzes peptide bonds within the transmembrane domain of substrates, including amyloid-[beta] precursor protein and Notch. [gamma]-Secretase is comprised of presenilin, nicastrin, APH-1, and PEN-2 which form a large multimeric membrane protein complex, the three-dimensional structure of which is unknown. To gain insight into the structure of this complex enzyme, we purified functional [gamma]-secretase complex reconstituted in Sf9 cells and analyzed it using negative stain electron microscopy and 3D reconstruction techniques. Analysis ...

Abstract

The [gamma]-secretase intramembrane protease cleaves many type I membrane proteins including amyloid precursor protein and Notch, generating peptide fragments that are important signaling components. In this issue of Cell, Shah et al. (2005) reveal the function of nicastrin, the largest member of the [gamma]-secretase complex. They show that the nicastrin extracellular domain is essential for recognition of substrate by the [gamma]-secretase. ...

Abstract

Data accumulated during the past two decades place amyloid [beta]-peptide (A[beta]) at center stage as the main perpetrator in initiating the pathological cascade that eventually leads to Alzheimer's disease. Consequently, significant resources have been allocated to identify and develop treatment strategies that alter the metabolism of A[beta]. The [gamma]-secretase protease has deservedly received attention as an attractive drug target, as it is directly involved in A[beta] biogenesis and determines the pathogenic potential of A[beta] by its heterogeneous catalytic action, generating peptides ...

Abstract

[gamma]-Secretase is a protease complex, which catalyzes the final of two subsequent cleavages of the [beta]-amyloid precursor protein (APP) to release the amyloid-[beta] peptide (A[beta]) implicated in Alzheimer's disease (AD) pathogenesis. In human cells, six [gamma]-secretase complexes exist, which are composed of either presenilin (PS) 1 or 2, the catalytic subunit, nicastrin, PEN-2, and either APH-1a (as S or L splice variants) or its homolog APH-1b. It is not known whether and how different APH-1 species contribute to the pathogenic activity ...

Abstract

10.1126/science.286.5440.735 ...

Abstract

beta-Amyloid peptides (Abeta) that form the senile plaques of Alzheimer disease consist mainly of 40- and 42-amino acid (Abeta 40 and Abeta 42) peptides generated from the cleavage of the amyloid precursor protein (APP). Generation of Abeta involves beta-secretase and gamma-secretase activities and is regulated by membrane trafficking of the proteins involved in Abeta production. Here we describe a new small molecule, EHT 1864, which blocks the Rac1 signaling pathways. In vitro, EHT 1864 blocks Abeta 40 and Abeta 42 production ...