Structural and regulatory elements of the interaction between amyloid-β protein precursor and Homer3.

Amyloid-β protein precursor (AβPP) metabolism and the accumulation of its derivative amyloid-β (Aβ) peptide in senile plaques have been considered key players in the development of Alzheimer's disease (AD). However, the mechanisms underlying the generation and the deposition of Aβ are not clear but emphasis has been given in the role of AβPP protein interactions that regulate its processing and offer a means to manipulate Aβ production. We have previously shown that AβPP interacts with members of the Homer protein family, which leads to inhibition of Aβ generation.

Stress, the stress system and the role of glucocorticoids.

All living organisms have developed a highly conserved and regulatory system, the stress system, to cope with a broad spectrum of stressful stimuli that threaten, or are perceived as threatening, their dynamic equilibrium or homeostasis. This neuroendocrine system consists of the hypothalamic-pituitary-adrenal (HPA) axis and the locus caeruleus/norepinephrine-autonomic nervous system. In parallel with the evolution of the homeostasis and stress concepts from ancient Greek to modern medicine, significant advances in the field of neuroendocrinology have identified the physiologic biochemical effector molecules of the stress response.

Calcium regulates the interaction of amyloid precursor protein with Homer3 protein.

Ca(2+) dysregulation is an important factor implicated in Alzheimer's disease pathogenesis. The mechanisms mediating the reciprocal regulation of Ca(2+) homeostasis and amyloid precursor protein (APP) metabolism, function, and protein interactions are not well known. We have previously shown that APP interacts with Homer proteins, which inhibit APP processing toward amyloid-β.

Protective effect of LRRK2 p.R1398H on risk of Parkinson's disease is independent of MAPT and SNCA variants.

The best validated susceptibility variants for Parkinson's disease are located in the α-synuclein (SNCA) and microtubule-associated protein tau (MAPT) genes. Recently, a protective p.N551K-R1398H-K1423K haplotype in the leucine-rich repeat kinase 2 (LRRK2) gene was identified, with p.

Population-specific frequencies for LRRK2 susceptibility variants in the Genetic Epidemiology of Parkinson's Disease (GEO-PD) Consortium.

Background: Variants within the leucine-rich repeat kinase 2 gene are recognized as the most frequent genetic cause of Parkinson's disease. Leucine-rich repeat kinase 2 variation related to disease susceptibility displays many features that reflect the nature of complex, late-onset sporadic disorders like Parkinson's disease.

Methods: The Genetic Epidemiology of Parkinson's Disease Consortium recently performed the largest genetic association study for variants in the leucine-rich repeat kinase 2 gene across 23 different sites in 15 countries.

Downregulation of AβPP enhances both calcium content of endoplasmic reticulum and acidic stores and the dynamics of store operated calcium channel activity.

The amyloid-β protein precursor (AβPP) is a type-1 transmembrane protein involved in Alzheimer's disease (AD). It has become increasingly evident that AβPP, its protein-protein interactions, and its proteolytical fragments may affect calcium homeostasis and vice versa. In addition, there is evidence that calcium dysregulation contributes to AD.

Selective neuroprotective effects of the S18Y polymorphic variant of UCH-L1 in the dopaminergic system.

Genetic studies have implicated the neuronal ubiquitin C-terminal hydrolase (UCH) protein UCH-L1 in Parkinson's disease (PD) pathogenesis. Moreover, the function of UCH-L1 may be lost in the brains of PD and Alzheimer's disease patients. We have previously reported that the UCH-L1 polymorphic variant S18Y, potentially protective against PD in population studies, demonstrates specific antioxidant functions in cell culture.

Association of LRRK2 exonic variants with susceptibility to Parkinson's disease: a case-control study.

Background: Background The leucine-rich repeat kinase 2 gene (LRRK2) harbours highly penetrant mutations that are linked to familial parkinsonism. However, the extent of its polymorphic variability in relation to risk of Parkinson's disease (PD) has not been assessed systematically. We therefore assessed the frequency of LRRK2 exonic variants in individuals with and without PD, to investigate the role of the variants in PD susceptibility.

The S18Y polymorphic variant of UCH-L1 confers an antioxidant function to neuronal cells.

A number of studies have associated the S18Y polymorphic variant of UCH-L1 with protection from sporadic Parkinson's Disease (PD). The mechanism involved in this protective function is unknown, but has generally been assumed to be linked to the ubiquitin-proteasome system (UPS). In the current study, we have investigated the effects of overexpression of UCH-L1 and its variants, including S18Y, in neuronal cells.

Differential effects of Parkin and its mutants on protein aggregation, the ubiquitin-proteasome system, and neuronal cell death in human neuroblastoma cells.

Mutations in Parkin, an E3 ligase, which participates in the ubiquitin-proteasome system (UPS), cause juvenile onset Parkinson's disease (PD). Some mutants aggregate upon over-expression, but the effects of such aggregation on the UPS and neuronal survival have not been characterized. We show in this study that transient over-expression of wild type (WT) Parkin or various mutants in human neuroblastoma cells leads to localized accumulation of green fluorescent protein (GFP(u)), an artificial proteasomal substrate, indicative of UPS dysfunction.