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The Journal of Biological Chemistry May 2013Presenilin and signal peptide peptidase are multispanning intramembrane-cleaving proteases with a conserved catalytic GxGD motif. Presenilin comprises the catalytic... (Review)
Review
Presenilin and signal peptide peptidase are multispanning intramembrane-cleaving proteases with a conserved catalytic GxGD motif. Presenilin comprises the catalytic subunit of γ-secretase, a protease responsible for the generation of amyloid-β peptides causative of Alzheimer disease. Signal peptide peptidase proteins are implicated in the regulation of the immune system. Both protease family proteins have been recognized as druggable targets for several human diseases, but their detailed structure still remains unknown. Recently, the x-ray structures of some archaeal GxGD proteases have been determined. We review the recent progress in biochemical and biophysical probing of the structure of these atypical proteases.
Topics: Alzheimer Disease; Amyloid Precursor Protein Secretases; Amyloid beta-Peptides; Animals; Archaea; Archaeal Proteins; Catalytic Domain; Humans; Membrane Proteins; Presenilins; Protein Structure, Tertiary; Serine Endopeptidases; Structure-Activity Relationship
PubMed: 23585568
DOI: 10.1074/jbc.R113.463281 -
ELife Jan 2017The high levels of serine (S) and threonine (T) residues within the Presenilin 1 (PS1) N-terminus and in the large hydrophilic loop region suggest that the enzymatic...
The high levels of serine (S) and threonine (T) residues within the Presenilin 1 (PS1) N-terminus and in the large hydrophilic loop region suggest that the enzymatic function of PS1/γ-secretase can be modulated by its 'phosphorylated' and 'dephosphorylated' states. However, the functional outcome of PS1 phosphorylation and its significance for Alzheimer's disease (AD) pathogenesis is poorly understood. Here, comprehensive analysis using FRET-based imaging reveals that activity-driven and Protein Kinase A-mediated PS1 phosphorylation at three domains (domain 1: T74, domain 2: S310 and S313, domain 3: S365, S366, and S367), with S367 being critical, is responsible for the PS1 pathogenic 'closed' conformation, and resulting increase in the Aβ42/40 ratio. Moreover, we have established novel imaging assays for monitoring PS1 conformation in vivo, and report that PS1 phosphorylation induces the pathogenic conformational shift in the living mouse brain. These phosphorylation sites represent potential new targets for AD treatment.
Topics: Alzheimer Disease; Animals; Disease Models, Animal; Fluorescence Resonance Energy Transfer; Mice; Optical Imaging; Phosphorylation; Presenilin-1; Protein Conformation; Protein Domains; Protein Processing, Post-Translational
PubMed: 28132667
DOI: 10.7554/eLife.19720 -
International Journal of Molecular... May 2021Perinatal asphyxia is mainly a brain disease leading to the development of neurodegeneration, in which a number of peripheral lesions have been identified; however,...
Perinatal asphyxia is mainly a brain disease leading to the development of neurodegeneration, in which a number of peripheral lesions have been identified; however, little is known about the expression of key genes involved in amyloid production by peripheral cells, such as lymphocytes, during the development of hypoxic-ischemic encephalopathy. We analyzed the gene expression of the , , and and by RT-PCR in the lymphocytes of post-asphyxia and control neonates. In all examined periods after asphyxia, decreased expression of the genes of the , and was noted in lymphocytes. Conversely, expression of and genes decreased on days 1-7 and 8-14 but increased after survival for more than 15 days. We believe that the expression of genes in lymphocytes could be a potential biomarker to determine the severity of the post-asphyxia neurodegeneration or to identify the underlying factors for brain neurodegeneration and get information about the time they occurred. This appears to be the first worldwide data on the role of the and genes associated with Alzheimer's disease in the dysregulation of neonatal lymphocytes after perinatal asphyxia.
Topics: Asphyxia; Case-Control Studies; Female; Gene Expression Regulation; Humans; Infant, Newborn; Lymphocytes; Male; Presenilin-1; Presenilin-2
PubMed: 34067945
DOI: 10.3390/ijms22105140 -
Biochemical Society Transactions Dec 2013Early-onset FAD (familial Alzheimer's disease) is caused by mutations of PS1 (presenilin 1), PS2 (presenilin 2) and APP (amyloid precursor protein). Beyond the effects... (Review)
Review
Early-onset FAD (familial Alzheimer's disease) is caused by mutations of PS1 (presenilin 1), PS2 (presenilin 2) and APP (amyloid precursor protein). Beyond the effects of PS1 mutations on proteolytic functions of the γ-secretase complex, mutant or deficient PS1 disrupts lysosomal function and Ca2+ homoeostasis, both of which are considered strong pathogenic factors in FAD. Loss of PS1 function compromises assembly and proton-pumping activity of the vacuolar-ATPase on lysosomes, leading to defective lysosomal acidification and marked impairment of autophagy. Additional dysregulation of cellular Ca2+ by mutant PS1 in FAD has been ascribed to altered ion channels in the endoplasmic reticulum; however, rich stores of Ca2+ in lysosomes are also abnormally released in PS1-deficient cells secondary to the lysosomal acidification defect. The resultant rise in cytosolic Ca2+ activates Ca2+-dependent enzymes, contributing substantially to calpain overactivation that is a final common pathway leading to neurofibrillary degeneration in all forms of AD (Alzheimer's disease). In the present review, we discuss the close inter-relationships among deficits of lysosomal function, autophagy and Ca2+ homoeostasis as a pathogenic process in PS1-related FAD and their relevance to sporadic AD.
Topics: Alzheimer Disease; Autophagy; Calcium; Humans; Lysosomes; Presenilin-1
PubMed: 24256243
DOI: 10.1042/BST20130201 -
Brain Structure & Function Mar 2010Mutations in presenilin-1 (PS1) and presenilin-2 (PS2) cause familial Alzheimer's disease (FAD). Presenilins influence multiple molecular pathways and are best known for... (Review)
Review
Mutations in presenilin-1 (PS1) and presenilin-2 (PS2) cause familial Alzheimer's disease (FAD). Presenilins influence multiple molecular pathways and are best known for their role in the gamma-secretase cleavage of type I transmembrane proteins including the amyloid precursor protein (APP). PS1 and PS2 FAD mutant transgenic mice have been generated using a variety of promoters. PS1-associated FAD mutations have also been knocked into the endogenous mouse gene. PS FAD mutant mice consistently show elevations of Abeta42 with little if any effect on Abeta40. When crossed with plaque forming APP FAD mutant lines, the PS1 FAD mutants cause earlier and more extensive plaque deposition. Although single transgenic PS1 or PS2 mice do not form plaques, they exhibit a number of pathological features including age-related neuronal and synaptic loss as well as vascular pathology. They also exhibit increased susceptibility to excitotoxic injury most likely on the basis of exaggerated calcium release from the endoplasmic reticulum. Electrophysiologically long-term potentiation in the hippocampus is increased in young PS1 FAD mutant mice but this effect appears to be lost with aging. In most studies neurogenesis in the adult hippocampus is also impaired by PS1 FAD mutants. Mice in which PS1 has been conditionally knocked out in adult forebrain on a PS2 null background (PS1/2 cDKO) develop a striking neurodegeneration that mimics AD neuropathology in being associated with neuronal and synaptic loss, astrogliosis and hyperphosphorylation of tau, although it is not accompanied by plaque deposits. The relevance of PS transgenic mice as models of AD is discussed.
Topics: Alzheimer Disease; Animals; Brain Chemistry; Disease Models, Animal; Hippocampus; Long-Term Potentiation; Mice; Mice, Transgenic; Nerve Degeneration; Plaque, Amyloid; Presenilins
PubMed: 19921519
DOI: 10.1007/s00429-009-0227-3 -
Neuron Apr 2003Gamma-Secretase cleaves the Amyloid Precursor Protein (APP) in its transmembrane domain, releasing the amyloid peptide Abeta. Abeta is the main constituent of the... (Review)
Review
Gamma-Secretase cleaves the Amyloid Precursor Protein (APP) in its transmembrane domain, releasing the amyloid peptide Abeta. Abeta is the main constituent of the amyloid plaques in the brains of patients suffering from Alzheimer's disease. Several other type I integral membrane proteins are also cleaved by this protease. Recent work indicates that gamma-Secretase is a multiprotein complex consisting of Presenilin, Nicastrin, Aph-1, and Pen-2 and that all four proteins are necessary for full proteolytic activity. Since several paralogs and alternatively spliced variants of at least Presenilin and Aph-1 have been identified as well, it is anticipated that gamma-Secretase is not a homogeneous activity. Gamma-Secretase is an interesting but complex drug target that challenges classical thinking about proteolytic processing and intracellular signaling.
Topics: Amyloid Precursor Protein Secretases; Animals; Aspartic Acid Endopeptidases; Endopeptidases; Humans; Membrane Glycoproteins; Membrane Proteins; Peptide Hydrolases; Presenilin-1; Presenilin-2; Protein Binding
PubMed: 12691659
DOI: 10.1016/s0896-6273(03)00205-8 -
Neurochemical Research 2007The biogenesis and accumulation of the beta amyloid protein (Abeta) is a key event in the cascade of oxidative and inflammatory processes that characterises Alzheimer's... (Review)
Review
The biogenesis and accumulation of the beta amyloid protein (Abeta) is a key event in the cascade of oxidative and inflammatory processes that characterises Alzheimer's disease. The presenilins and its interacting proteins play a pivotal role in the generation of Abeta from the amyloid precursor protein (APP). In particular, three proteins (nicastrin, aph-1 and pen-2) interact with presenilins to form a large multi-subunit enzymatic complex (gamma-secretase) that cleaves APP to generate Abeta. Reconstitution studies in yeast and insect cells have provided strong evidence that these four proteins are the major components of the gamma-secretase enzyme. Current research is directed at elucidating the roles that each of these protein play in the function of this enzyme. In addition, a number of presenilin interacting proteins that are not components of gamma-secretase play important roles in modulating Abeta production. This review will discuss the components of the gamma-secretase complex and the role of presenilin interacting proteins on gamma-secretase activity.
Topics: Alzheimer Disease; Amyloid Precursor Protein Secretases; Amyloid beta-Peptides; Animals; Aspartic Acid Endopeptidases; Humans; Membrane Glycoproteins; Membrane Proteins; Nucleocytoplasmic Transport Proteins; Presenilins; Protein Binding; Substrate Specificity
PubMed: 16944319
DOI: 10.1007/s11064-006-9131-x -
Neurochemical Research Aug 2021Early-onset Alzheimer's disease (AD) is associated with variants in amyloid precursor protein (APP) and presenilin (PSEN) 1 and 2. It is increasingly recognized... (Review)
Review
Early-onset Alzheimer's disease (AD) is associated with variants in amyloid precursor protein (APP) and presenilin (PSEN) 1 and 2. It is increasingly recognized that patients with AD experience undiagnosed focal seizures. These AD patients with reported seizures may have worsened disease trajectory. Seizures in epilepsy can also lead to cognitive deficits, neuroinflammation, and neurodegeneration. Epilepsy is roughly three times more common in individuals aged 65 and older. Due to the numerous available antiseizure drugs (ASDs), treatment of seizures has been proposed to reduce the burden of AD. More work is needed to establish the functional impact of seizures in AD to determine whether ASDs could be a rational therapeutic strategy. The efficacy of ASDs in aged animals is not routinely studied, despite the fact that the elderly represents the fastest growing demographic with epilepsy. This leaves a particular gap in understanding the discrete pathophysiological overlap between hyperexcitability and aging, and AD more specifically. Most of our preclinical knowledge of hyperexcitability in AD has come from mouse models that overexpress APP. While these studies have been invaluable, other drivers underlie AD, e.g. PSEN2. A diversity of animal models should be more frequently integrated into the study of hyperexcitability in AD, which could be particularly beneficial to identify novel therapies. Specifically, AD-associated risk genes, in particular PSENs, altogether represent underexplored contributors to hyperexcitability. This review assesses the available studies of ASDs administration in clinical AD populations and preclinical studies with AD-associated models and offers a perspective on the opportunities for further therapeutic innovation.
Topics: Aging; Alzheimer Disease; Animals; Anticonvulsants; Comorbidity; Epilepsy; Humans; Mutation; Presenilin-1; Presenilin-2; Seizures
PubMed: 33929683
DOI: 10.1007/s11064-021-03332-y -
Biochimica Et Biophysica Acta Mar 2007Alzheimer's disease is the most prevalent form of dementia. Neuropathogenesis is proposed to be a result of the accumulation of amyloid beta peptides in the brain... (Review)
Review
Alzheimer's disease is the most prevalent form of dementia. Neuropathogenesis is proposed to be a result of the accumulation of amyloid beta peptides in the brain together with oxidative stress mechanisms and neuroinflammation. The presenilin proteins are central to the gamma-secretase cleavage of the amyloid prescursor protein (APP), releasing the amyloid beta peptide. Point mutations in the presenilin genes lead to cases of familial Alzheimer's disease by increasing APP cleavage resulting in excess amyloid beta formation. This review discusses the molecular mechanism of Alzheimer's disease with a focus on the presenilin genes. Alternative splicing of transcripts from these genes and how these may function in several disease states is discussed. There is an emphasis on the importance of animal models in elucidating the molecular mechanisms behind the development of Alzheimer's disease and how the zebrafish, Danio rerio, can be used as a model organism for analysis of presenilin function and Alzheimer's disease pathogenesis.
Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Disease Models, Animal; Mice; Point Mutation; Presenilins; Zebrafish
PubMed: 17208417
DOI: 10.1016/j.bbadis.2006.12.001 -
TheScientificWorldJournal Jun 2003Alzheimer's dementia (AD) is the most common degenerative disorder of the central nervous system. Although the onset of dementia is above 65 years of age in the majority... (Review)
Review
Alzheimer's dementia (AD) is the most common degenerative disorder of the central nervous system. Although the onset of dementia is above 65 years of age in the majority of the patients (late-onset AD, LOAD), a small subgroup of patients develops AD before 65 years of age (early-onset AD, EOAD). To date 3 genes responsible for EOAD have been identified: the amyloid precursor protein gene (APP), presenilin 1 (PSEN1) and presenilin 2 (PSEN2). PSEN1 is the most frequently mutated EOAD gene with a mutation frequency of 18 to 50% in autosomal dominant EOAD. In addition, the epsilon4 allele of the gene encoding apolipoprotein E (APOE) was identified as a risk factor for both LOAD and EOAD. Many studies reported other susceptibility genes, but the APOEepsilon4 alelle has been the only risk factor that was consistently replicated in all AD populations. Extensive cell biology research in the past ten years led to the hypothesis that the 4 EOAD genes lead to AD through a common biological pathway resulting in abnormal APP processing by subtle different mechanisms. Now, transgenic mice are produced to study the influence of EOAD mutations in vivo, eventually leading to the development of novel therapeutic strategies.
Topics: Alzheimer Disease; Amino Acid Sequence; Animals; Disease Models, Animal; Humans; Membrane Proteins; Molecular Epidemiology; Molecular Sequence Data; Presenilin-1; Presenilin-2
PubMed: 12847300
DOI: 10.1100/tsw.2003.39