The amyloid β-protein (Aβ) deposited in Alzheimer’s disease (AD) is a normally secreted proteolytic product of the amyloid β-protein precursor (APP). Generation of Aβ from the APP requires two sequential proteolytic events: an initial β-secretase cleavage at the amino terminus of the Aβ sequence followed by γ-secretase cleavage at the carboxyl terminus of Aβ. We describe the development of a ro...

AD (Alzheimer's disease) is a neurodegenerative disease characterized by a gradual loss of neurons and the accumulation of neurotoxic Aβ (amyloid β-peptide) and hyperphosphorylated tau. The discovery of mutations in three genes, PSEN1 (presenilin 1), PSEN2 (presenilin 2) and APP (amyloid precursor protein), in patients with FAD (familial AD) has made an important contribution towards an underst...

Alzheimer’s disease (AD) is a tenacious neurodegenerative dementia, characterized clinically by progressive loss of memory, cognitive dysfunction, and behavioral abnormalities, accompanied by the accumulation of intracellular neurofibrillary tangles (NFTs), neuropil threads, as well as extracellular amyloid-beta containing senile plaques, cerebrovascular amyloid-beta deposits, and selective ner...

Gamma-secretase is an enzyme complex that mediates both Notch signaling and beta-amyloid precursor protein (APP) processing, resulting in the generation of Notch intracellular domain, APP intracellular domain, and the amyloid beta peptide (Abeta), the latter playing a central role in Alzheimer disease (AD). By a hitherto undefined mechanism, the activity of gamma-secretase gives rise to Abeta p...

BACKGROUND Mutations linked to early onset, familial forms of Alzheimer's disease (FAD) are found most frequently in PSEN1, the gene encoding presenilin-1 (PS1). Together with nicastrin (NCT), anterior pharynx-defective protein 1 (APH1), and presenilin enhancer 2 (PEN2), the catalytic subunit PS1 constitutes the core of the γ-secretase complex and contributes to the proteolysis of the amyloid p...

The cleavage of the transmembrane amyloid precursor protein (APP) by beta-secretase leaves the C-terminal fragment of APP, C99, anchored in the plasma membrane. C99 is subsequently processed by gamma-secretase, an unusual aspartyl protease activity largely dependent on presenilin (PS), generating the amyloid beta-peptide (Abeta) that accumulates in the brain of patients with Alzheimer's disease...

The 19-transmembrane multisubunit γ-secretase complex generates the amyloid β-peptide (Aβ) of Alzheimer's disease (AD) by intramembrane proteolysis of the β-amyloid precursor protein (APP). Despite substantial advances in elucidating how this protein complex functions, the effect of the local membrane lipid microenvironment on γ-secretase cleavage of substrates is still poorly understood. Using...

The γ-secretase complex is a member of the family of intramembrane cleaving proteases, involved in the generation of the Aβ peptides in Alzheimer disease. One of the four subunits of the complex, presenilin, harbors the catalytic site, although the role of the other three subunits is less well understood. Here, we studied the role of the smallest subunit, Pen-2, in vivo and in vitro. We found a...

Mutations in PSEN1 and PSEN2 genes, encoding presenilin 1 (PS1) and presenilin 2 (PS2), respectively, cause autosomal-dominant Alzheimer’s disease (ADAD) (1, 2). The precise mechanism by which PS1 mutations lead to AD is under active investigation. Multiple theories have been suggested to explain the role of PS1 and PS2 mutations on AD pathogenesis, including the effects on γ-secretase activity...