共查询到20条相似文献,搜索用时 31 毫秒
1.
Alzheimer disease (AD) is the most common neurodegenerative disorder worldwide and is at present, incurable. The accumulation
of toxic amyloid-beta (Aβ) peptide aggregates in AD brain is thought to trigger the extensive synaptic loss and neurodegeneration
linked to cognitive decline, an idea that underlies the ‘amyloid hypothesis’ of AD etiology in both the familal (FAD) and
sporadic forms of the disease. Genetic mutations causing FAD also result in the dysregulation of neuronal calcium (Ca2+) handling and may contribute to AD pathogenesis, an idea termed the ‘calcium hypothesis’ of AD. Mutations in presenilin proteins
account for majority of FAD cases. Presenilins function as catalytic subunit of γ-secretase involved in generation of Aβ peptide
Recently, we discovered that presenilns function as low-conductance, passive ER Ca2+ leak channels, independent of γ-secretase activity. We further discovered that many FAD mutations in presenilins result in
loss of ER Ca2+ leak function activity and Ca2+ overload in the ER. These results provided potential explanation for abnormal Ca2+ signaling observed in FAD cells with mutations in presenilns. Our latest work on studies of ER Ca2+ leak channel function of presenilins and implications of these findings for understanding AD pathogenesis are discussed in
this article. 相似文献
2.
Krishna Midde Ryan Rich Ashwini Saxena Ignacy Gryczynski Julian Borejdo Hriday K. Das 《Cell biochemistry and biophysics》2014,70(2):923-932
Presenilin-1 (PS1) protein acts as passive ER Ca2+ leak channels that facilitate passive Ca2+ leak across ER membrane. Mutations in the gene encoding PS1 protein cause neurodegeneration in the brains of patients with familial Alzheimer’s disease (FAD). FADPS1 mutations abrogate the function of ER Ca2+ leak channel activity in human neuroblastoma SK-N-SH cells in vitro (Das et al., J Neurochem 122(3):487–500, 2012) and in mouse embryonic fibroblasts. Consequently, genetic deletion or mutations of the PS1 gene cause calcium (Ca2+) signaling abnormalities leading to neurodegeneration in FAD patients. By analogy with other known ion channels it has been proposed that the functional PS1 channels in ER may be multimers of several PS1 subunits. To test this hypothesis, we conjugated the human PS1 protein with an NH2-terminal YFP-tag and a COOH-terminal CFP-tag. As expected YFP–PS1, and PS1–CFP were found to be expressed on the plasma membranes by TIRF microscopy, and both these fusion proteins increased ER Ca2+ leak channel activity similar to PS1 (WT) in SK-N-SH cells, as determined by functional calcium imaging. PS1–CFP was either expressed alone or together with YFP–PS1 into SK-N-SH cell line and the interaction between YFP–PS1 and PS1–CFP was determined by Förster resonance energy transfer analysis. Our results suggest interaction between YFP–PS1 and PS1–CFP confirming the presence of a dimeric or multimeric form of PS1 in SK-N-SH cells. Lateral diffusion of PS1–CFP and YFP–PS1 in the plasma membrane of SK-N-SH cells was measured in the absence or in the presence of glycerol by fluorescence correlation spectroscopy to show that both COOH-terminal and NH2-terminal of human PS1 are located on the cytoplasmic side of the plasma membrane. Therefore, we conclude that both COOH-terminal and NH2-terminal of human PS1 may also be oriented on the cytosolic side of ER membrane. 相似文献
3.
Jie Liu Charlene Supnet Suya Sun Hua Zhang Levi Good Elena Popugaeva Ilya Bezprozvanny 《Channels (Austin, Tex.)》2014,8(3):230-242
Dysregulated endoplasmic reticulum (ER) calcium (Ca2+) signaling is reported to play an important role in Alzheimer disease (AD) pathogenesis. The role of ER Ca2+ release channels, the ryanodine receptors (RyanRs), has been extensively studied in AD models and RyanR expression and activity are upregulated in the brains of various familial AD (FAD) models. The objective of this study was to utilize a genetic approach to evaluate the importance of RyanR type 3 (RyanR3) in the context of AD pathology. 相似文献
4.
《Cell calcium》2019
An imbalance in Ca2+ homeostasis represents an early event in the pathogenesis of Alzheimer’s disease (AD). Presenilin-1 and -2 (PS1 and PS2) mutations, the major cause of familial AD (FAD), have been extensively associated with alterations in different Ca2+ signaling pathways, in particular those handled by storage compartments. However, FAD-PSs effect on organelles Ca2+ content is still debated and the mechanism of action of mutant proteins is unclear.To fulfil the need of a direct investigation of intracellular stores Ca2+ dynamics, we here present a detailed and quantitative single-cell analysis of FAD-PSs effects on organelle Ca2+ handling using specifically targeted, FRET (Fluorescence/Förster Resonance Energy Transfer)-based Ca2+ indicators. In SH-SY5Y human neuroblastoma cells and in patient-derived fibroblasts expressing different FAD-PSs mutations, we directly measured Ca2+ concentration within the main intracellular Ca2+ stores, e.g., Endoplasmic Reticulum (ER) and Golgi Apparatus (GA) medial- and trans-compartment. We unambiguously demonstrate that the expression of FAD-PS2 mutants, but not FAD-PS1, in either SH-SY5Y cells or FAD patient-derived fibroblasts, is able to alter Ca2+ handling of ER and medial-GA, but not trans-GA, reducing, compared to control cells, the Ca2+ content within these organelles by partially blocking SERCA (Sarco/Endoplasmic Reticulum Ca2+-ATPase) activity. Moreover, by using a cytosolic Ca2+ probe, we show that the expression of both FAD-PS1 and -PS2 reduces the Ca2+ influx activated by stores depletion (Store-Operated Ca2+ Entry; SOCE), by decreasing the expression levels of one of the key molecules, STIM1 (STromal Interaction Molecule 1), controlling this pathway.Our data indicate that FAD-linked PSs mutants differentially modulate the Ca2+ content of intracellular stores yet leading to a complex dysregulation of Ca2+ homeostasis, which represents a common disease phenotype of AD. 相似文献
5.
MJ Kipanyula L Contreras E Zampese C Lazzari AK Wong P Pizzo C Fasolato T Pozzan 《Aging cell》2012,11(5):885-893
Mutations in amyloid precursor protein (APP), and presenilin‐1 and presenilin‐2 (PS1 and PS2) have causally been implicated in Familial Alzheimer’s Disease (FAD), but the mechanistic link between the mutations and the early onset of neurodegeneration is still debated. Although no consensus has yet been reached, most data suggest that both FAD‐linked PS mutants and endogenous PSs are involved in cellular Ca2+ homeostasis. We here investigated subcellular Ca2+ handling in primary neuronal cultures and acute brain slices from wild type and transgenic mice carrying the FAD‐linked PS2‐N141I mutation, either alone or in the presence of the APP Swedish mutation. Compared with wild type, both types of transgenic neurons show a similar reduction in endoplasmic reticulum (ER) Ca2+ content and decreased response to metabotropic agonists, albeit increased Ca2+ release induced by caffeine. In both transgenic neurons, we also observed a higher ER–mitochondria juxtaposition that favors increased mitochondrial Ca2+ uptake upon ER Ca2+ release. A model is described that integrates into a unifying hypothesis the contradictory effects on Ca2+ homeostasis of different PS mutations and points to the relevance of these findings in neurodegeneration and aging. 相似文献
6.
《Channels (Austin, Tex.)》2013,7(3):230-242
Dysregulated endoplasmic reticulum (ER) calcium (Ca2+) signaling is reported to play an important role in Alzheimer disease (AD) pathogenesis. The role of ER Ca2+ release channels, the ryanodine receptors (RyanRs), has been extensively studied in AD models and RyanR expression and activity are upregulated in the brains of various familial AD (FAD) models. The objective of this study was to utilize a genetic approach to evaluate the importance of RyanR type 3 (RyanR3) in the context of AD pathology. 相似文献
7.
《Cell calcium》2017
We have studied in HeLa cells the molecular nature of the 2-APB induced ER Ca2+ leak using synthetic Ca2+ indicators that report changes in both the cytoplasmic ([Ca2+]i) and the luminal ER ([Ca2+]ER) Ca2+ concentrations. We have tested the hypothesis that Orai channels participate in the 2-APB-induced ER Ca2+ leak that was characterized in the companion paper. The expression of the dominant negative Orai1 E106A mutant, which has been reported to block the activity of all three types of Orai channels, inhibited the effect of 2-APB on the [Ca2+]ER but did not decrease the ER Ca2+ leak after thapsigargin (TG). Orai3 channel, but neither Orai1 nor Orai2, colocalizes with expressed IP3R and only Orai3 channel supported the 2-APB-induced ER Ca2+ leak, while Orai1 and Orai2 inhibited this type of ER Ca2+ leak. Decreasing the expression of Orai3 inhibited the 2-APB-induced ER Ca2+ leak but did not modify the ER Ca2+ leak revealed by inhibition of SERCA pumps with TG. However, reducing the expression of Orai3 channel resulted in larger [Ca2+]i response after TG but only when the ER store had been overloaded with Ca2+ by eliminating the acidic internal Ca2+ store with bafilomycin. These data suggest that Orai3 channel does not participate in the TG-revealed ER Ca2+ leak but forms an ER Ca2+ leak channel that is limiting the overloading with Ca2+ of the ER store. 相似文献
8.
Chau DM Crump CJ Villa JC Scheinberg DA Li YM 《The Journal of biological chemistry》2012,287(21):17288-17296
Presenilin-1 (PS1) is the catalytic subunit of γ-secretase, and mutations in this protein cause familial Alzheimer Disease (FAD). However, little is known about how these mutations affect the active site of γ-secretase. Here, we show that PS1 mutations alter the S2 subsite within the active site of γ-secretase using a multiple photoaffinity probe approach called "photophore walking." Moreover, we developed a unique in vitro assay with a biotinylated recombinant Notch1 substrate and demonstrated that PS1 FAD mutations directly and significantly reduced γ-secretase activity for Notch1 cleavage. Substitution of the Notch Cys-1752 residue, which interacts with the S2 subsite, with Val, Met, or Ile has little effect on wild-type PS1 but leads to more efficient substrates for mutant PS1s. This study indicates that alteration of this S2 subsite plays an important role in determining the activity and specificity of γ-secretase for APP and Notch1 processing, which provides structural basis and insights on how certain PS1 FAD mutations lead to AD pathogenesis. 相似文献
9.
10.
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 understanding of the disease aetiology; however, a complete molecular mechanism is still lacking. Both presenilins belong to the γ-secretase complex, and serve as the catalytic entity needed for the final cleavage of APP into Aβ. PSEN only functions within the γ-secretase complex through intra- and inter-molecular interactions with three other membrane components, including nicastrin, Aph-1 (anterior pharynx defective-1) and Pen-2 (PSEN enhancer-2). However, although the list of γ-secretase substrates is still expanding, other non-catalytic activities of presenilins are also increasing the complexity behind its molecular contribution towards AD. These γ-secretase-independent roles are so far mainly attributed to PSEN1, including the transport of membrane proteins, cell adhesion, ER (endoplasmic reticulum) Ca(2+) regulation and cell signalling. In the present minireview, we discuss the current understanding of the γ-secretase-independent roles of PSENs and their possible implications in respect of AD. 相似文献
11.
Fujita H Kato T Watanabe N Takahashi T Kitagawa S 《Archives of biochemistry and biophysics》2011,(1):121-60
Calpain inhibitors induce pertussis toxin (PTx)-sensitive chemotaxis in human neutrophils and monocytes. Here, we show that various calpain inhibitors (PD150606, PD151746, N-acetyl-Leu-Leu-Nle-CHO [ALLN], N-acetyl-Leu-Leu-Met-CHO [ALLM], and calpeptin) and γ-secretase inhibitor I induced PTx-sensitive increase in cytoplasmic free Ca2+ ([Ca2+]i) in human neutrophils and neutrophil migration. HEK-293 cells stably expressing human formyl peptide receptor (hFPR) or hFPR-like 1 (hFPRL1) displayed stimulus-specific increase in [Ca2+]i in response to calpain inhibitors (PD150606, PD151746, ALLN, ALLM, MG-132, and calpeptin), γ-secretase inhibitor I, and N-formyl-Met-Leu-Phe. Parent HEK-293 cells also displayed PTx-sensitive increase in [Ca2+]i in response to calpeptin and γ-secretase inhibitor I, whereas they displayed PTx-resistant increase in [Ca2+]i in response to MG-132. MDL-28170 induced neither an increase in [Ca2+]i in neutrophils and HEK-293 cells nor neutrophil migration. Ionomycin-induced cleavage of talin (a substrate of calpain) in neutrophils was inhibited by all inhibitors used here. These findings suggest that potent calpain inhibitors could stimulate phagocyte functions via activation of hFPR, hFPRL1 and/or other G-protein coupled receptors depending on the inhibitors used. 相似文献
12.
An increase in the intracellular calcium ion concentration ([Ca2+]) impacts a diverse range of cell functions, including adhesion, motility, gene expression and proliferation. Elevation of intracellular calcium ion (Ca2+) regulates various cellular events after the stimulation of cells. Initial increase in Ca2+ comes from the endoplasmic reticulum (ER), intracellular storage space. However, the continuous influx of extracellular Ca2+ is required to maintain the increased level of Ca2+ inside cells. Store-operated Ca2+ entry (SOCE) manages this process, and STIM1, a newly discovered molecule, has a unique and essential role in SOCE. STIM1 can sense the exhaustion of Ca2+ in the ER, and activate the SOC channel in the plasma membrane, leading to the continuous influx of extracellular Ca2+. STIM1 senses the status of the intracellular Ca2+ stores via a luminal N-terminal Ca2+-binding EF-hand domain. Dissociation of Ca2+ from this domain induces the clustering of STIM1 to regions of the ER that lie close to the plasma membrane, where it regulates the activity of the store-operated Ca2+ channels/entry (calcium-release-activated calcium channels/entry). In this review, we summarize the mechanism by which STIM1 regulates SOCE, and also its role in the control of mast cell functions and allergic responses. 相似文献
13.
Rachel E. Milner Konrad S. Famulski Marek Michalak 《Molecular and cellular biochemistry》1992,112(1):1-13
In this paper we review some of the large quantities of information currently available concerning the identification, structure and function of Ca2+-binding proteins of endoplasmic and sarcoplasmic reticulum membranes. The review places particular emphasis on identification and discussion of Ca2+ storage proteins in these membranes. We believe that the evidence reviewed here supports the contention that the Ca2+-binding capacity of both calsequestrin and calreticulin favor their contribution as the major Ca2+-binding proteins of muscle and nonmuscle cells, respectively. Other Ca2+-binding proteins discovered in both endoplasmic reticulum and sarcoplasmic reticulum membranes probably contribute to the overall Ca2+ storage capacity of these membrane organelles, and they also play other important functional role such as posttranslational modification of newly synthesized proteins, a cytoskeletal (structural) function, or movement of Ca2+ within the lumen of the sarcoplasmic/endoplasmic reticulum towards the storage sites.Abbreviations SR
Sarcoplasmic Reticulum
- ER
Endoplasmic Reticulum
- InsP3
Inositol 1,4,5-trisphosphate
- SDS-PAGE
Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis
- PDI
Protein Disulphide Isomerase
- T3BP
Thyroid Hormone Binding Protein
- Grp
Glucose regulated proteins
- HCP
Histidine-rich Ca2+ binding Protein
- LDL
Low Density Lipoprotein 相似文献
14.
Presenilins form ER Ca2+ leak channels, a function disrupted by familial Alzheimer's disease-linked mutations 总被引:1,自引:0,他引:1
Tu H Nelson O Bezprozvanny A Wang Z Lee SF Hao YH Serneels L De Strooper B Yu G Bezprozvanny I 《Cell》2006,126(5):981-993
Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder. Mutations in presenilins 1 and 2 (PS1 and PS2) account for approximately 40% of familial AD (FAD) cases. FAD mutations and genetic deletions of presenilins have been associated with calcium (Ca(2+)) signaling abnormalities. We demonstrate that wild-type presenilins, but not PS1-M146V and PS2-N141I FAD mutants, can form low-conductance divalent-cation-permeable ion channels in planar lipid bilayers. In experiments with PS1/2 double knockout (DKO) mouse embryonic fibroblasts (MEFs), we find that presenilins account for approximately 80% of passive Ca(2+) leak from the endoplasmic reticulum. Deficient Ca(2+) signaling in DKO MEFs can be rescued by expression of wild-type PS1 or PS2 but not by expression of PS1-M146V or PS2-N141I mutants. The ER Ca(2+) leak function of presenilins is independent of their gamma-secretase activity. Our data suggest a Ca(2+) signaling function for presenilins and provide support for the "Ca(2+) hypothesis of AD." 相似文献
15.
Ha-Na Woo Jong-Sung Park A-Ryeong Gwon Dong-Gyu Jo 《Biochemical and biophysical research communications》2009,390(4):1093-1097
Cleavage of the amyloid precursor protein (APP) by γ-secretase generates a neurotoxic amyloid β-peptide (Aβ) that is thought to be associated with the neurodegeneration observed in Alzheimer’s disease (AD) patients. Presenilin is the catalytic member of the γ-secretase proteolytic complex and mutations in presenilins are the major cause of early-onset familial Alzheimer’s disease. In addition to APP, γ-secretase substrates include Notch1 homologues, Notch ligands Delta and Jagged, and additional type I membrane proteins, raising concerns about mechanism-based toxicities that might arise as a consequence of inhibiting γ-secretase. Notch signaling is involved in tumorigenesis as well as in determining the fates of neural and nonneural cells during development and in adults. Alterations in proteolysis of the Notch by γ-secretase could be involved in the pathogenesis of AD. Inconsistently, several recent observations have indicated that enhanced Notch signaling and expression could be instrumental in neurodegeneration in AD. Therefore, detailed and precise study of Notch signaling in AD is important for elucidating diverse mechanisms of pathogenesis and potentially for treating and preventing Alzheimer’s disease. 相似文献
16.
T. S. Novorodovskaya 《Neurophysiology》2009,41(6):380-388
The objects of the study were single-compartment mathematical models corresponding to a fragment of the dendrite of a cerebellar
Purkinje neuron. The fragments contained the mitochondria (model 1) or a cistern of the endoplasmic reticulum, ER (model 2),
functioning as calcium stores. With simulating single excitatory synaptic actions, we examined the dependence of the dynamics
of intracellular Ca2+ levels on the maximum rate of Ca2+ exchange between the cytosol and these stores, as well as on the intensity of the diffusion flow into adjacent organelle-free
regions. The plasma membrane of the compartment had ion channels (including those of the synaptic current) and the calcium
pump characteristic of the mentioned neurons. The model equations took into account Ca2+ exchange between the cytosol, extracellular environment, and organellar stores, as well as the diffusion process. In model
1, the mitochondria exchanged Ca2+ with the cytosol through the uniporter and sodium-calcium exchanger; mitochondrial processes, such as the tricarboxylic acid
cycle and aerobic cellular respiration, were also included. In model 2, the ER membrane had the calcium pump, leak channels,
and channels of calcium-induced and inositol-3-phosphate-dependent Ca2+ release. The stores (mitochondria or ER) occupied 36% of the total volume of the compartment. An increase in the maximum
rate of calcium exchange with the stores led to a proportional decrease in the peak Ca2+ concentrations in the cytosol ([Ca2+]i), more pronounced in the case of the ER; the Ca2+ concentration in both types of stores increased significantly. Due to the higher storage rate, the ER was able to absorb
several times greater amounts of Ca2+ than the mitochondria did. With smaller diffusion flux (e.g., similarly to the case of diffusion from a larger-sized head
into the neck of the dendritic spine), the intensity of cytosolic transients increased at fixed kinetics of flux exchange
with the stores. Therefore, the organellar stores can significantly modulate not only the intensity but also the time course
of changes in the intracellular Ca2+ levels. 相似文献
17.
Santeri Kiviluoto Tomas Luyten Lars Schneider Dmitrij Lisak Diego Rojas-Rivera Kirsten Welkenhuyzen Ludwig Missaen Humbert De Smedt Jan B. Parys Claudio Hetz Axel Methner Geert Bultynck 《Cell calcium》2013
Bax Inhibitor-1 (BI-1) is an evolutionarily conserved six-transmembrane domain endoplasmic reticulum (ER)-localized protein that protects against ER stress-induced apoptotic cell death. This function is closely connected to its ability to lower steady-state ER Ca2+ levels. Recently, we elucidated BI-1's Ca2+-channel pore in the C-terminal part of the protein and identified the critical amino acids of its pore. Based on these insights, a Ca2+-channel pore-dead mutant BI-1 (BI-1D213R) was developed. We determined whether BI-1 behaves as a bona fide H+/Ca2+ antiporter or as an ER Ca2+-leak channel by investigating the effect of pH on unidirectional Ca2+-efflux rates. At pH 6.8, wild-type BI-1 expression in BI-1−/− cells increased the ER Ca2+-leak rate, correlating with its localization in the ER compartment. In contrast, BI-1D231R expression in BI-1−/−, despite its ER localization, did not increase the ER Ca2+-leak rate. However, at pH < 6.8, the BI-1-mediated ER Ca2+ leak was blocked. Finally, a peptide representing the Ca2+-channel pore of BI-1 promoting Ca2+ flux from the ER was used. Lowering the pH from 6.8 to 6.0 completely abolished the ability of the BI-1 peptide to mediate Ca2+ flux from the ER. We propose that this pH dependence is due to two aspartic acid residues critical for the function of the Ca2+-channel pore and located in the ER membrane-dipping domain, which facilitates the protonation of these residues. 相似文献
18.
Amongst the cellular cacophony of altered signals in Alzheimer’s disease (AD), disrupted Ca2+ homeostasis and consequential endoplasmic reticulum (ER) stress signals have been recognized as key determinants of neuron fate. This altered Ca2+ state is accompanied by a failing sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump, which has been recognized as a causal feature of the underlying disease state. Repair of the Ca2+ dyshomeostasis represents a putative drug target via alleviation of ER stress and rescue of injured neurons, effectively modifying the AD state. Herein, we report a small molecule SERCA activator that rescues brain cells and raises ER Ca2+ in vitro, and shows efficacy in the APP/PS1 double transgenic mouse model of Alzheimer’s disease. These results support SERCA activation as a therapeutic target for AD. 相似文献
19.
《Cell calcium》2018
Store-operated calcium entry (SOCE) is the flow of calcium ions (Ca2+) into cells in response to the depletion of intracellular Ca2+ stores that reside predominantly in the endoplasmic reticulum (ER). The role of SOCE has been relatively well understood for non-excitable cells. It is mediated mostly by the ER Ca2+ sensor STIM1 and plasma membrane Ca2+ channel Orai1 and serves to sustain Ca2+ signaling and refill ER Ca2+ stores. In contrast, because of the complexity of Ca2+ influx mechanisms that are present in excitable cells, our knowledge about the function of neuronal SOCE (nSOCE) is still nascent. This review summarizes the available data on the molecular components of nSOCE and their relevance to neuronal signaling. We also present evidence of disturbances of nSOCE in neurodegenerative diseases (namely Alzheimer’s disease, Huntington’s disease, and Parkinson’s disease) and traumatic brain injury. The emerging important role of nSOCE in neuronal physiology and pathology makes it a possible clinical target. 相似文献
20.
Chera L Maarouf Ian D Daugs Salvatore Spina Ruben Vidal Tyler A Kokjohn RLyle Patton Walter M Kalback Dean C Luehrs Douglas G Walker Eduardo M Castaño Thomas G Beach Bernardino Ghetti Alex E Roher 《Molecular neurodegeneration》2008,3(1):1-18