Lysosomes are central players in cellular catabolism, signaling, and metabolic regulation. Cellular and environmental stresses that damage lysosomal membranes can compromise their function and ...release toxic content into the cytoplasm. Here, we examine how cells respond to osmotic stress within lysosomes. Using sensitive assays of lysosomal leakage and rupture, we examine acute effects of the osmotic disruptant glycyl-L-phenylalanine 2-naphthylamide (GPN). Our findings reveal that low concentrations of GPN rupture a small fraction of lysosomes, but surprisingly trigger Ca
release from nearly all. Chelating cytoplasmic Ca
makes lysosomes more sensitive to GPN-induced rupture, suggesting a role for Ca
in lysosomal membrane resilience. GPN-elicited Ca
release causes the Ca
-sensor Apoptosis Linked Gene-2 (ALG-2), along with Endosomal Sorting Complex Required for Transport (ESCRT) proteins it interacts with, to redistribute onto lysosomes. Functionally, ALG-2, but not its ESCRT binding-disabled ΔGF
splice variant, increases lysosomal resilience to osmotic stress. Importantly, elevating juxta-lysosomal Ca
without membrane damage by activating TRPML1 also recruits ALG-2 and ESCRTs, protecting lysosomes from subsequent osmotic rupture. These findings reveal that Ca
, through ALG-2, helps bring ESCRTs to lysosomes to enhance their resilience and maintain organelle integrity in the face of osmotic stress.
Endocytic sorting of amyloid precursor protein (APP) governed by the vacuolar protein sorting (Vps10) family of receptors plays a decisive role in controlling the outcome of APP proteolytic ...processing and the generation of amyloid β (Aβ) peptides, the key pathogenic factor of Alzheimer's disease (AD). This study provides the first evidence to our knowledge that a G protein-coupled receptor, namely, the α
2A
adrenergic receptor, modulates APP endocytic sorting and promotes Aβ generation through disrupting APP interaction with a Vps10 family protein, sorting-related receptor with A repeat. Significantly, blockade of α
2A
AR by a clinical antagonist reduces AD-related pathology and ameliorates cognitive deficits in an AD transgenic model, suggesting repurposing clinical α
2
AR antagonists as a new direction for AD treatment.
Accumulation of amyloid β (Aβ) peptides in the brain is the key pathogenic factor driving Alzheimer’s disease (AD). Endocytic sorting of amyloid precursor protein (APP) mediated by the vacuolar protein sorting (Vps10) family of receptors plays a decisive role in controlling the outcome of APP proteolytic processing and Aβ generation. Here we report for the first time to our knowledge that this process is regulated by a G protein-coupled receptor, the α
2A
adrenergic receptor (α
2A
AR). Genetic deficiency of the α
2A
AR significantly reduces, whereas stimulation of this receptor enhances, Aβ generation and AD-related pathology. Activation of α
2A
AR signaling disrupts APP interaction with a Vps10 family receptor, sorting-related receptor with A repeat (SorLA), in cells and in the mouse brain. As a consequence, activation of α
2A
AR reduces Golgi localization of APP and concurrently promotes APP distribution in endosomes and cleavage by β secretase. The α
2A
AR is a key component of the brain noradrenergic system. Profound noradrenergic dysfunction occurs consistently in patients at the early stages of AD. α
2A
AR-promoted Aβ generation provides a novel mechanism underlying the connection between noradrenergic dysfunction and AD. Our study also suggests α
2A
AR as a previously unappreciated therapeutic target for AD. Significantly, pharmacological blockade of the α
2A
AR by a clinically used antagonist reduces AD-related pathology and ameliorates cognitive deficits in an AD transgenic model, suggesting that repurposing clinical α
2
AR antagonists would be an effective therapeutic strategy for AD.
Low-Cost Sorting Network Circuits Using Unary Processing Najafi, M. Hassan; Lilja, David. J.; Riedel, Marc D. ...
IEEE transactions on very large scale integration (VLSI) systems,
08/2018, Letnik:
26, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Sorting is a common task in a wide range of applications from signal and image processing to switching systems. For applications that require high performance, sorting is often performed in hardware ...with application-specified integrated circuits or field-programmable gate arrays. Hardware cost and power consumption are the dominant concerns. The usual approach is to wire up a network of compare-and-swap units in a configuration called the Batcher (or bitonic) network. Such networks can readily be pipelined. This paper proposes a novel area-efficient and power-efficient approach to sorting networks, based on "unary processing." In unary processing, numbers are encoded uniformly by a sequence of one value (say 1) followed by a sequence of the other value (say 0) in a stream of 0's and 1's with the value defined by the fraction of 1's in the stream. Synthesis results of complete sorting networks show up to 92% area and power saving compared to the conventional binary implementations. However, the latency increases. To mitigate the increased latency, this paper uses a novel time-encoding of data. The approach is validated with two implementations of an important application of sorting: median filtering. The result is a low cost, energy-efficient implementation of median filtering with only a slight accuracy loss, compared to conventional implementations.
The MEME Suite Bailey, Timothy L; Johnson, James; Grant, Charles E ...
Nucleic acids research,
07/2015, Letnik:
43, Številka:
W1
Journal Article
Recenzirano
Odprti dostop
The MEME Suite is a powerful, integrated set of web-based tools for studying sequence motifs in proteins, DNA and RNA. Such motifs encode many biological functions, and their detection and ...characterization is important in the study of molecular interactions in the cell, including the regulation of gene expression. Since the previous description of the MEME Suite in the 2009 Nucleic Acids Research Web Server Issue, we have added six new tools. Here we describe the capabilities of all the tools within the suite, give advice on their best use and provide several case studies to illustrate how to combine the results of various MEME Suite tools for successful motif-based analyses. The MEME Suite is freely available for academic use at http://meme-suite.org, and source code is also available for download and local installation.
Retromer mediates sequence-directed cargo exit from endosomes to support both endosome-to-Golgi (retrograde transport) and endosome-to-plasma membrane (recycling) itineraries. It is not known whether ...these trafficking functions require cargos to exit endosomes separately via distinct transport intermediates or whether the same retromer-coated carriers can support both itineraries. We addressed this question by comparing human Wntless (Wls) and β2 adrenergic receptor (β2AR), which require retromer physiologically for retrograde transport and recycling, respectively. We show here by direct visualization in living cells that both cargos transit primarily the same endosomes and exit via shared transport vesicles generated from a retromer-coated endosome domain. While both Wls and β2AR clearly localize to the same retromer-coated endosome domains, Wls is consistently enriched more strongly. This enrichment difference is determined by distinct motifs present in the cytoplasmic tail of each cargo, with Wls using tandem Φ-X-L/M motifs and β2AR using a PDZ motif. Exchanging these determinants reverses the enrichment phenotype of each cargo but does not change cargo itinerary, verifying the multifunctional nature of retromer and implying that additional sorting must occur downstream. Quantitative differences in the degree of cargo enrichment instead underlie a form of kinetic sorting that impacts the rate of cargo delivery via both itineraries and determines the ability of β2AR to activate its cognate G protein transducer locally from endosomes. We propose that mammalian retromer forms a multifunctional membrane coat that supports shared cargo exit for divergent trafficking itineraries and regulates signaling from endosomes.
•Recycling and retrograde cargos exit endosomes via shared retromer domains•The same retromer domains accumulate cargos with distinct sorting motifs•Sorting motifs determine endosome exit kinetics but not downstream itinerary•GPCR exit kinetics inversely correlate with local G protein activation at endosomes
Varandas et al. provide evidence that mammalian retromer forms a multifunctional membrane coat that allows shared endosome exit of cargos with divergent destinations and controls G protein activation by GPCRs at endosomes.
The endosomal deubiquitylase USP8 has profound effects on endosomal morphology and organisation. Previous reports have proposed both positive (EGFR, MET) and negative roles in the down‐regulation of ...receptors (Frizzled, Smoothened). Here we report an additional influence of USP8 on the retromer‐dependent shuttling of ci‐M6PR between the sorting endosome and biosynthetic pathway. Depletion of USP8 leads to a steady state redistribution of ci‐M6PR from the Trans‐Golgi Network (TGN) to endosomal compartments. Consequently we observe a defect in sorting of lysosomal enzymes, evidenced by increased levels of unprocessed Cathepsin D, which is secreted into the medium. The normal distribution of receptor can be restored by expression of siRNA‐resistant USP8 but not by a catalytically inactive mutant or a truncated form, lacking a MIT domain required for endosomal localisation. We suggest that effects of USP8 depletion may reflect the loss of ESCRT‐0 components which associate with retromer components Vps35 and SNX1, whilst failure to efficiently deliver lysosomal enzymes may also contribute to the observed block in receptor tyrosine kinase degradation.
The endosomal deubiquitylase, USP8, controls many aspects of the endocytic pathway. These include stability of the ESCRT‐0 complex and governance of the fate of activated receptor tyrosine kinases such as EGFR. Here we extend this reach to the recycling of ci‐M6PR from endosomes to Trans‐Golgi network. Following USP8 depletion, ci‐M6PR accumulates in endosomes. The consequent secretion of cathepsin D into the extracellular milieu may provide a pharmacodynamic marker for USP8 inhibitors, which are under development.
The order-of-addition (OofA) experiment has received a great deal of attention in the recent literature. The primary goal of the OofA experiment is to identify the optimal order in a sequence of m ...components. All the existing methods are model-dependent and are limited to small number of components. The appropriateness of the resulting optimal order heavily depends on (a) the correctness of the underlying assumed model, and (b) the goodness of model fitting. Moreover, these methods are not applicable to deal with large m (e.g.,
). With this in mind, this article proposes an efficient adaptive methodology, building upon the quick-sort algorithm, to explore the optimal order without any model specification. Compared to the existing work, the run sizes of the proposed method needed to achieve the optimal order are much smaller. Theoretical supports are given to illustrate the effectiveness of the proposed method. The proposed method is able to obtain the optimal order for large m (e.g.,
). Numerical experiments are used to demonstrate the effectiveness of the proposed method.
Obesity-associated morbidity is exacerbated by abdominal obesity, which can be measured as the waist-to-hip ratio adjusted for the body mass index (WHRadjBMI). Here we identify genes associated with ...obesity and WHRadjBMI and characterize allele-sensitive enhancers that are predicted to regulate WHRadjBMI genes in women. We found that several waist-to-hip ratio-associated variants map within primate-specific Alu retrotransposons harboring a DNA motif associated with adipocyte differentiation. This suggests that a genetic component of adipose distribution in humans may involve co-option of retrotransposons as adipose enhancers. We evaluated the role of the strongest female WHRadjBMI-associated gene, SNX10, in adipose biology. We determined that it is required for human adipocyte differentiation and function and participates in diet-induced adipose expansion in female mice, but not males. Our data identify genes and regulatory mechanisms that underlie female-specific adipose distribution and mediate metabolic dysfunction in women.
This article proposes a multiobjective sizing method of the retired battery integrating with the photovoltaic solar energy used for the electric vehicle charging station (EVCS) against the charging ...demand uncertainty. The proposed size optimization approach employs non-dominated sorting genetic algorithm II (NSGA-II) to minimize the renewable energy waste, energy purchased from the external grid, as well as the cost characterized by the net present value produced in 20 years. Especially for the remaining life prediction of retired batteries, this article leverages the calendar-life degradation model by integrating the battery cycle-life counting method. Also, in this article, the charging demand uncertainty is built as different charging patterns for various EVCS scenarios with different combinations of fast- and slow-charging demand. Furthermore, the technoeconomic attractions of retired batteries are verified by a comprehensive comparison with the new batteries. Case studies are implemented with real-world data, and the results show that under the proposed sizing method, the EVCS could achieve a 29.4% cost reduction in the long-term operation with the retired batteries.
Multicomponent supramolecular systems can be used to achieve different properties and new behaviors compared to their corresponding single component systems. Here, a two‐component system is used, ...showing that a non‐gelling component modifies the assembly of the gelling component, allowing access to co‐assembled structures that cannot be formed from the gelling component alone. The systems are characterized across multiple length scales, from the molecular level by NMR and CD spectroscopy to the microstructure level by SANS and finally to the material level using nanoindentation and rheology. By exploiting the enhanced mechanical properties achieved through addition of the second component, multicomponent noodles are formed with superior mechanical properties to those formed by the single‐component system. Furthermore, the non‐gelling component can be triggered to crystallize within the multicomponent noodles, allowing the preparation of new types of hierarchical composite noodles.
Multicomponent assembly of 2NapFF with the structurally similar functionalized dipeptide 2NapLG causes changes to the formed first‐order supramolecular structures. These changes to assembly allow access to new properties and behaviors. This multicomponent system can be used to form mechanically robust supramolecular noodles. Through a change in external conditions (a reduction in pH), crystals can be formed within these noodles.
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