scholarly journals Lysosome and calcium dysregulation in Alzheimer's disease: partners in crime

2013 ◽  
Vol 41 (6) ◽  
pp. 1495-1502 ◽  
Author(s):  
MaryKate McBrayer ◽  
Ralph A. Nixon
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Proton Pumping ◽  
Calcium Dysregulation ◽  
Lysosomal Function ◽  
Pathogenic Factors ◽  
Presenilin 2 ◽  
Ad Alzheimer’S Disease ◽  
Pathogenic Process ◽  
Lysosomal Acidification

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.

scholarly journals Intracellular Calcium Dysregulation by the Alzheimer’s Disease-Linked Protein Presenilin 2

2020 ◽  
Vol 21 (3) ◽  
pp. 770 ◽  
Author(s):  
Luisa Galla ◽  
Nelly Redolfi ◽  
Tullio Pozzan ◽  
Paola Pizzo ◽  
Elisa Greotti
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Autosomal Dominant ◽  
Amyloid Β ◽  
Presenilin 1 ◽  
Calcium Dysregulation ◽  
Aβ Peptides ◽  
Functional Consequences ◽  
Presenilin 2 ◽  
Amyloid Cascade

Alzheimer’s disease (AD) is the most common form of dementia. Even though most AD cases are sporadic, a small percentage is familial due to autosomal dominant mutations in amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes. AD mutations contribute to the generation of toxic amyloid β (Aβ) peptides and the formation of cerebral plaques, leading to the formulation of the amyloid cascade hypothesis for AD pathogenesis. Many drugs have been developed to inhibit this pathway but all these approaches currently failed, raising the need to find additional pathogenic mechanisms. Alterations in cellular calcium (Ca2+) signaling have also been reported as causative of neurodegeneration. Interestingly, Aβ peptides, mutated presenilin-1 (PS1), and presenilin-2 (PS2) variously lead to modifications in Ca2+ homeostasis. In this contribution, we focus on PS2, summarizing how AD-linked PS2 mutants alter multiple Ca2+ pathways and the functional consequences of this Ca2+ dysregulation in AD pathogenesis.

In Vivo Perturbation of Lysosomal Function Promotes Neurodegeneration in the PS1M146V/APPK670N,M671L Mouse Model of Alzheimer's Disease Pathology

2003 ◽  
pp. 687-695 ◽  
Author(s):  
Ralph A. Nixon ◽  
Paul M. Mathews ◽  
Anne M. Cataldo ◽  
Panaiyur S. Mohan ◽  
Stephen D. Schmidt ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Lysosomal Function ◽  
Model Of Alzheimer’S Disease

scholarly journals The Influence of Endoproteolytic Processing of Familial Alzheimer's Disease Presenilin 2 on Aβ42 Amyloid Peptide Formation

1999 ◽  
Vol 274 (49) ◽  
pp. 35233-35239 ◽  
Author(s):  
Helmut Jacobsen ◽  
Dieter Reinhardt ◽  
Manfred Brockhaus ◽  
Daniel Bur ◽  
Christine Kocyba ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Peptide ◽  
Familial Alzheimer’S Disease ◽  
Peptide Formation ◽  
Presenilin 2 ◽  
Familial Alzheimer's Disease

The proteins BACE1 and BACE2 and β-secretase activity in normal and Alzheimer's disease brain

2007 ◽  
Vol 35 (3) ◽  
pp. 574-576 ◽  
Author(s):  
J.H. Stockley ◽  
C. O'Neill
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Protein Levels ◽  
Rate Limiting Step ◽  
Secretase Activity ◽  
Aβ Amyloid ◽  
Ad Alzheimer’S Disease ◽  
And Function

The insidious progression of AD (Alzheimer's disease) is believed to be linked closely to the production, accumulation and aggregation of the ∼4.5 kDa protein fragment called Aβ (amyloid β-peptide). Aβ is produced by sequential cleavage of the amyloid precursor protein by two enzymes referred to as β- and γ-secretase. β-Secretase is of central importance, as it catalyses the rate-limiting step in the production of Aβ and was identified 7 years ago as BACE1 (β-site APP-cleaving enzyme 1). Soon afterwards, its homologue BACE2 was discovered, and both proteins represent a new subclass of the aspartyl protease family. Studies examining the regulation and function of β-secretase in the normal and AD brain are central to the understanding of excessive production of Aβ in AD, and in targeting and normalizing this β-secretase process if it has gone awry in the disease. Several reports indicate this, showing increased β-secretase activity in AD, with recent findings by our group showing changes in β-secretase enzyme kinetics in AD brain caused by an increased Vmax. This article gives a brief review of studies which have examined BACE1 protein levels and β-secretase activity in control and AD brain, considering further the expression of BACE2 in the human brain.

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