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1.
Cell ; 184(1): 133-148.e20, 2021 01 07.
Article in English | MEDLINE | ID: mdl-33338421

ABSTRACT

Flaviviruses pose a constant threat to human health. These RNA viruses are transmitted by the bite of infected mosquitoes and ticks and regularly cause outbreaks. To identify host factors required for flavivirus infection, we performed full-genome loss of function CRISPR-Cas9 screens. Based on these results, we focused our efforts on characterizing the roles that TMEM41B and VMP1 play in the virus replication cycle. Our mechanistic studies on TMEM41B revealed that all members of the Flaviviridae family that we tested require TMEM41B. We tested 12 additional virus families and found that SARS-CoV-2 of the Coronaviridae also required TMEM41B for infection. Remarkably, single nucleotide polymorphisms present at nearly 20% in East Asian populations reduce flavivirus infection. Based on our mechanistic studies, we propose that TMEM41B is recruited to flavivirus RNA replication complexes to facilitate membrane curvature, which creates a protected environment for viral genome replication.


Subject(s)
Flavivirus Infections/genetics , Flavivirus/physiology , Membrane Proteins/metabolism , Animals , Asian People/genetics , Autophagy , COVID-19/genetics , COVID-19/metabolism , COVID-19/virology , CRISPR-Cas Systems , Cell Line , Flavivirus Infections/immunology , Flavivirus Infections/metabolism , Flavivirus Infections/virology , Gene Knockout Techniques , Genome-Wide Association Study , Host-Pathogen Interactions , Humans , Immunity, Innate , Membrane Proteins/genetics , Polymorphism, Single Nucleotide , SARS-CoV-2/physiology , Virus Replication , Yellow fever virus/physiology , Zika Virus/physiology
2.
Mol Cell ; 67(6): 974-989.e6, 2017 Sep 21.
Article in English | MEDLINE | ID: mdl-28890335

ABSTRACT

During autophagosome formation in mammalian cells, isolation membranes (IMs; autophagosome precursors) dynamically contact the ER. Here, we demonstrated that the ER-localized metazoan-specific autophagy protein EPG-3/VMP1 controls ER-IM contacts. Loss of VMP1 causes stable association of IMs with the ER, thus blocking autophagosome formation. Interaction of WIPI2 with the ULK1/FIP200 complex and PI(3)P contributes to the formation of ER-IM contacts, and these interactions are enhanced by VMP1 depletion. VMP1 controls contact formation by promoting SERCA (sarco[endo]plasmic reticulum calcium ATPase) activity. VMP1 interacts with SERCA and prevents formation of the SERCA/PLN/SLN inhibitory complex. VMP1 also modulates ER contacts with lipid droplets, mitochondria, and endosomes. These ER contacts are greatly elevated by the SERCA inhibitor thapsigargin. Calmodulin acts as a sensor/effector to modulate the ER contacts mediated by VMP1/SERCA. Our study provides mechanistic insights into the establishment and disassociation of ER-IM contacts and reveals that VMP1 modulates SERCA activity to control ER contacts.


Subject(s)
Autophagosomes/enzymology , Endoplasmic Reticulum/enzymology , Intracellular Membranes/enzymology , Membrane Proteins/metabolism , Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism , Animals , Animals, Genetically Modified , Autophagy-Related Protein-1 Homolog/genetics , Autophagy-Related Protein-1 Homolog/metabolism , Autophagy-Related Proteins , COS Cells , CRISPR-Cas Systems , Caenorhabditis elegans/enzymology , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Calcium-Binding Proteins/metabolism , Chlorocebus aethiops , Genotype , HEK293 Cells , HeLa Cells , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lipid Droplets/metabolism , Membrane Proteins/genetics , Muscle Proteins/metabolism , Phenotype , Phosphatidylinositol Phosphates/metabolism , Proteolipids/metabolism , RNA Interference , Sarcoplasmic Reticulum Calcium-Transporting ATPases/genetics , Transfection
3.
Article in English | MEDLINE | ID: mdl-39466176

ABSTRACT

Osteosarcoma (OS) is a highly malignant tumor, and chemotherapy resistance is a major challenge in the treatment of this disease. This study aims to explore the role of the CLTC-VMP1 gene fusion in the mechanism of chemotherapy resistance in OS and investigate its molecular mechanisms in mediating energy metabolism reprogramming by regulating autophagy and apoptosis balance. Using single-cell transcriptome analysis, the heterogeneity of OS cells and their correlation with resistance to platinum drugs were revealed. Cisplatin-resistant cell lines were established in human OS cell lines for subsequent experiments. Based on transcriptomic analysis, the importance of VMP1 in chemotherapy resistance was confirmed. Lentiviral vectors overexpressing or interfering with VMP1 were used, and it was observed that inhibiting VMP1 could reverse cisplatin resistance, promote cell apoptosis, and inhibit autophagy, as well as mitochondrial respiration and glycolysis. Furthermore, the presence of CLTC-VMP1 gene fusion was validated, and its ability to regulate autophagy and apoptosis balance, promote mitochondrial respiration, and glycolysis was demonstrated. Mouse model experiments further confirmed the promoting effect of CLTC-VMP1 on tumor growth and chemotherapy resistance. In summary, the CLTC-VMP1 gene fusion mediates energy metabolism reprogramming by regulating autophagy and apoptosis balance, which promotes chemotherapy resistance in OS.

4.
EMBO Rep ; 23(2): e53894, 2022 02 03.
Article in English | MEDLINE | ID: mdl-35044051

ABSTRACT

The endoplasmic reticulum (ER) is a central hub for the biogenesis of various organelles and lipid-containing structures. Recent studies suggest that vacuole membrane protein 1 (VMP1) and transmembrane protein 41B (TMEM41B), multispanning ER membrane proteins, regulate the formation of many of these ER-derived structures, including autophagosomes, lipid droplets, lipoproteins, and double-membrane structures for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. VMP1 and TMEM41B possess a DedA domain that is widely distributed not only in eukaryotes but also in prokaryotes and predicted to adopt a characteristic structure containing two reentrant loops. Furthermore, recent studies show that both proteins have lipid scrambling activity. Based on these findings, the potential roles of VMP1 and TMEM41B in the dynamic remodeling of ER membranes and the biogenesis of ER-derived structures are discussed.


Subject(s)
Autophagy , Membrane Proteins/genetics , Endoplasmic Reticulum/genetics , Humans
5.
Inflamm Res ; 73(4): 563-580, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38411635

ABSTRACT

BACKGROUND: Altered expression of vacuole membrane protein 1 (VMP1) has recently been observed in the context of multiple sclerosis and Parkinson's disease (PD). However, how changes in VMP1 expression may impact pathogenesis has not been explored. OBJECTIVE: This study aimed to characterize how altered VMP1 expression affects NLRP3 inflammasome activation and mitochondrial function. METHODS: VMP1 expression was depleted in a monocytic cell line using CRISPR-Cas9. The effect of VMP1 on NLRP3 inflammasome activation was examined by stimulating cells with LPS and ATP or α-synuclein fibrils. Inflammasome activation was determined by caspase-1 activation using both a FLICA assay and a biosensor as well as by the release of proinflammatory molecules measured by ELISA. RNA-sequencing was utilized to define global gene expression changes resulting from VMP1 deletion. SERCA activity and mitochondrial function were investigated using various fluorescence microscopy-based approaches including a novel method that assesses the function of individual mitochondria in a cell. RESULTS: Here, we report that genetic deletion of VMP1 from a monocytic cell line resulted in increased NLRP3 inflammasome activation and release of proinflammatory molecules. Examination of the VMP1-dependent changes in these cells revealed that VMP1 deficiency led to decreased SERCA activity and increased intracellular [Ca2+]. We also observed calcium overload in mitochondria in VMP1 depleted cells, which was associated with mitochondrial dysfunction and release of mitochondrial DNA into the cytoplasm and the extracellular environment. CONCLUSIONS: Collectively, these studies reveal VMP1 as a negative regulator of inflammatory responses, and we postulate that decreased expression of VMP1 can aggravate the inflammatory sequelae associated with neurodegenerative diseases like PD.


Subject(s)
Inflammasomes , Mitochondrial Diseases , Humans , Inflammasomes/metabolism , Membrane Proteins/metabolism , Mitochondrial Diseases/genetics , Mitochondrial Diseases/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Vacuoles/metabolism
6.
Bioessays ; 44(12): e2100261, 2022 12.
Article in English | MEDLINE | ID: mdl-36285664

ABSTRACT

The asymmetric distribution of lipids, maintained by flippases/floppases and scramblases, plays a pivotal role in various physiologic processes. Scramblases are proteins that move phospholipids between the leaflets of the lipid bilayer of the cellular membrane in an energy-independent manner. Recent studies have indicated that viral infection is closely related to cellular lipid distribution. The level and distribution of phosphatidylserine (PtdSer) in cells have been demonstrated to be critical regulators of viral infections. Previous studies have supported that the infection of human immunodeficiency virus (HIV), Zika virus, Ebola virus (EBOV), influenza virus, and dengue fever virus require the externalization of phospholipids mediated by scramblases, which are also involved in the pathogenicity of the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this review, we review the relationship of scramblases with viruses and the potential viral effector proteins that might utilize host scramblases.


Subject(s)
COVID-19 , Virus Diseases , Zika Virus Infection , Zika Virus , Humans , SARS-CoV-2 , Phosphatidylserines/metabolism , Phospholipids/metabolism
7.
Cryobiology ; 117: 104977, 2024 Oct 14.
Article in English | MEDLINE | ID: mdl-39368531

ABSTRACT

Critical cooling and warming rates (CCR and CWR) are two important calorimetric properties of cryoprotective agents (CPA) solutions, and achieving these rates is generally regarded as the critical criterion for successful vitrification and rewarming. In 1996, Peyridieu et al. discovered that the measured critical rates are reduced inside kidney tissue equilibrated with 30 % (w/w) 2,3-butanediol compared to its free CPA solution. In general, they found a ∼5-fold reduction for CCR and a >100-fold reduction for CWR. However, to our knowledge, no follow-up studies have been conducted. We revisit this important concept, understanding that tissues never fully equilibrate with full-strength 100 % CPAs during perfusion. We therefore performed measurements in a range of dilutions of two commonly employed CPA cocktails, including 75-100 % VS55 (41.25-55.00 % w/v) and 90-100 % VMP (48.60-54.00 % w/v) equilibrated with kidney tissues vs. free solution. The measured reduction in the kidney was up to 5-fold for CCR and 9-fold for CWR. After discussing possible mechanisms for this effect, curves that fit the dilution to the observed reduction in critical rate were constructed to allow extrapolation for differentially loaded tissues, which can guide the follow-up studies to find the more concentrated CPA (>8.4 M VMP) in the M22 family to achieve human-sized kidney vitrification and rewarming.

8.
Proc Natl Acad Sci U S A ; 118(16)2021 04 20.
Article in English | MEDLINE | ID: mdl-33850023

ABSTRACT

The autophagy protein ATG2, proposed to transfer bulk lipid from the endoplasmic reticulum (ER) during autophagosome biogenesis, interacts with ER residents TMEM41B and VMP1 and with ATG9, in Golgi-derived vesicles that initiate autophagosome formation. In vitro assays reveal TMEM41B, VMP1, and ATG9 as scramblases. We propose a model wherein membrane expansion results from the partnership of a lipid transfer protein, moving lipids between the cytosolic leaflets of apposed organelles, and scramblases that reequilibrate the leaflets of donor and acceptor organelle membranes as lipids are depleted or augmented. TMEM41B and VMP1 are implicated broadly in lipid homeostasis and membrane dynamics processes in which their scrambling activities likely are key.


Subject(s)
Autophagy-Related Proteins/metabolism , Phospholipid Transfer Proteins/metabolism , Autophagosomes/metabolism , Autophagy/physiology , Autophagy-Related Proteins/physiology , Carrier Proteins/metabolism , Endoplasmic Reticulum/metabolism , Humans , Lipid Metabolism/physiology , Lipids/physiology , Membrane Proteins/metabolism , Membranes/metabolism , Models, Biological , Models, Theoretical , Organelle Biogenesis , Phospholipid Transfer Proteins/physiology
9.
Int J Mol Sci ; 25(7)2024 Mar 28.
Article in English | MEDLINE | ID: mdl-38612567

ABSTRACT

Autophagy, a catabolic process orchestrating the degradation of proteins and organelles within lysosomes, is pivotal for maintaining cellular homeostasis. However, its dual role in cancer involves preventing malignant transformation while fostering progression and therapy resistance. Vacuole Membrane Protein 1 (VMP1) is an essential autophagic protein whose expression, per se, triggers autophagy, being present in the whole autophagic flux. In pancreatic cancer, VMP1-whose expression is linked to the Kirsten Rat Sarcoma Virus (KRAS) oncogene-significantly contributes to disease promotion, progression, and chemotherapy resistance. This investigation extends to breast cancer, colon cancer, hepatocellular carcinoma, and more, highlighting VMP1's nuanced nature, contingent on specific tissue contexts. The examination of VMP1's interactions with micro-ribonucleic acids (miRNAs), including miR-21, miR-210, and miR-124, enhances our understanding of its regulatory network in cancer. Additionally, this article discusses VMP1 gene fusions, especially with ribosomal protein S6 kinase B1 (RPS6KB1), shedding light on potential implications for tumor malignancy. By deciphering the molecular mechanisms linking VMP1 to cancer progression, this exploration paves the way for innovative therapeutic strategies to disrupt these pathways and potentially improve treatment outcomes.


Subject(s)
Carcinoma, Hepatocellular , Colonic Neoplasms , Liver Neoplasms , Membrane Proteins , MicroRNAs , Humans , Autophagy/genetics , Membrane Proteins/genetics , Membrane Proteins/physiology , MicroRNAs/genetics
10.
Aten Primaria ; 2024 Jan 24.
Article in Spanish | MEDLINE | ID: mdl-38272784

ABSTRACT

Gender violence has multiple and serious consequences for the health of victims and their families, hence the reason for the important role that the health system plays in addressing it. Health professionals have a key role in the response, which must include early detection, care, and follow-up; actions in which primary care, because of its privileged position in the system, can play a fundamental part. This article establishes the necessary characteristics for the intervention to be effective: comprehensive care, multidisciplinary approach, intersectoral coordination, and integrated service provision; all of it community-oriented, person-centered, and adapted to its context (social factors and vulnerabilities) with an intersectional approach. The woman, her sons and daughters, and other cohabitants, as well as the perpetrator, are considered the object of intervention in the response, and specific guidelines for action are provided for detection, care, and follow-up. Reorientation of interventions, with emphasis on a community approach, is also proposed.

11.
J Cell Sci ; 134(8)2021 04 15.
Article in English | MEDLINE | ID: mdl-33771928

ABSTRACT

TMEM41B and VMP1 are endoplasmic reticulum (ER)-localizing multi-spanning membrane proteins required for ER-related cellular processes such as autophagosome formation, lipid droplet homeostasis and lipoprotein secretion in eukaryotes. Both proteins have a VTT domain, which is similar to the DedA domain found in bacterial DedA family proteins. However, the molecular function and structure of the DedA and VTT domains (collectively referred to as DedA domains) and the evolutionary relationships among the DedA domain-containing proteins are largely unknown. Here, we conduct a remote homology search and identify a new clade consisting mainly of bacterial proteins of unknown function that are members of the Pfam family PF06695. Phylogenetic analysis reveals that the TMEM41, VMP1, DedA and PF06695 families form a superfamily with a common origin, which we term the DedA superfamily. Coevolution-based structural prediction suggests that the DedA domain contains two reentrant loops facing each other in the membrane. This topology is biochemically verified by the substituted cysteine accessibility method. The predicted structure is topologically similar to that of the substrate-binding region of Na+-coupled glutamate transporter solute carrier 1 (SLC1) proteins. A potential ion-coupled transport function of the DedA superfamily proteins is discussed. This article has an associated First Person interview with the joint first authors of the paper.


Subject(s)
Endoplasmic Reticulum , Membrane Proteins , Bacterial Proteins , Endoplasmic Reticulum/genetics , Humans , Intracellular Membranes , Membrane Proteins/genetics , Phylogeny
12.
Sensors (Basel) ; 23(4)2023 Feb 12.
Article in English | MEDLINE | ID: mdl-36850661

ABSTRACT

Due to their lack of driving controllability, overweight vehicles are a big threat to road safety. The proposed method for a moving passenger car load estimation is capable of detecting an overweight vehicle, and thus it finds its application in road safety improvement. The weight of a car's load entering or leaving a considered zone, e.g., industrial facility, a state, etc., is also of concern in many applications, e.g., surveillance. Dedicated vehicle weight-in-motion measurement systems generally use expensive load sensors that also require deep intervention in the road while being installed and also are calibrated only for heavy trucks. In this paper, a vehicle magnetic profile (VMP) is used for defining a load parameter proportional to the passenger vehicle load. The usefulness of the proposed load parameter is experimentally demonstrated in field tests. The sensitivity of the VMP to the load change results from the fact that the higher load decreases the vehicle clearance value which in turn increases the VMP. It is also shown that a slim inductive-loop sensors allows the building of a load estimation system, with a maximum error around 30 kg, which allows approximate determination of the number of passengers in the car. The presented proof of concept extends the functionality of inductive loops, already installed in the road, for acquiring other traffic parameters, e.g., moving vehicle axle-to-axle distance measurement, to road safety and surveillance related applications.

13.
Int J Mol Sci ; 24(16)2023 Aug 19.
Article in English | MEDLINE | ID: mdl-37629161

ABSTRACT

Autophagy is a tightly regulated catabolic process involved in the degradation and recycling of proteins and organelles. Ubiquitination plays an important role in the regulation of autophagy. Vacuole Membrane Protein 1 (VMP1) is an essential autophagy protein. The expression of VMP1 in pancreatic cancer stem cells carrying the activated Kirsten rat sarcoma viral oncogene homolog (KRAS) triggers autophagy and enables therapy resistance. Using biochemical and cellular approaches, we identified ubiquitination as a post-translational modification of VMP1 from the initial steps in autophagosome biogenesis. VMP1 remains ubiquitinated as part of the autophagosome membrane throughout autophagic flux until autolysosome formation. However, VMP1 is not degraded by autophagy, nor by the ubiquitin-proteasomal system. Mass spectrometry and immunoprecipitation showed that the cell division cycle protein cdt2 (Cdt2), the substrate recognition subunit of the E3 ligase complex associated with cancer, cullin-RING ubiquitin ligase complex 4 (CRL4), is a novel interactor of VMP1 and is involved in VMP1 ubiquitination. VMP1 ubiquitination decreases under the CRL inhibitor MLN4924 and increases with Cdt2 overexpression. Moreover, VMP1 recruitment and autophagosome formation is significantly affected by CRL inhibition. Our results indicate that ubiquitination is a novel post-translational modification of VMP1 during autophagy in human tumor cells. VMP1 ubiquitination may be of clinical relevance in tumor-cell-therapy resistance.


Subject(s)
Membrane Proteins , Neoplasms , Protein Processing, Post-Translational , Humans , Autophagy/genetics , Macroautophagy , Membrane Proteins/metabolism , Ubiquitin , Ubiquitination
14.
Int J Mol Sci ; 23(16)2022 Aug 11.
Article in English | MEDLINE | ID: mdl-36012210

ABSTRACT

Caudal fin regeneration is regulated by a variety of mechanisms, but the role of long non-coding RNA (lncRNA) has rarely been studied. The present study aimed to describe the landscape of lncRNAs during caudal fin regeneration using whole transcriptome sequencing, and then to conduct a functional study on the target lncRNAs using real-time fluorescent quantitative PCR (RT-qPCR), in situ hybridization, and the CRISPR/Cas9 method for lncRNA gene knockout. The results of the transcriptome sequencing showed that a total of 381 lncRNAs were differentially expressed, among which ENSDART00000154324 (lincRNA-154324) was found to be highly related to caudal fin regeneration, and thus it was chosen as the target lncRNA for the subsequent functional study. The results regarding the temporal and spatial expression of lincRNA-154324 and the gene knockout results from CRISPR/Cas9 indicated that lincRNA-154324 is involved in the caudal fin regeneration of zebrafish. Importantly, we serendipitously discovered that the cis correlation coefficient between lincRNA-154324 and its neighboring gene vacuole membrane protein 1 (vmp1) is extremely high, and they are essential for the process of caudal fin regeneration. Moreover, studies have found that vmp1 plays an important role in protein secretion, organelle formation, multicellular development, and autophagy. Collectively, our result may provide a framework for the identification and analysis of lncRNAs involved in the regeneration of the zebrafish caudal fin.


Subject(s)
RNA, Long Noncoding , Zebrafish , Animals , In Situ Hybridization , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Wound Healing , Zebrafish/metabolism , Zebrafish Proteins/genetics , Zebrafish Proteins/metabolism
15.
Molecules ; 27(15)2022 Aug 01.
Article in English | MEDLINE | ID: mdl-35956862

ABSTRACT

In addition to wax, propolis is a mixture of resins, terpenes, and etheric and aromatic oils. This composition supports its very strong biochemical activity that affects bee health. Bee colonies are externally exposed to the activity of other different pharmacologically active substances and toxic agents used in beekeeping procedures, veterinary interventions, and the environment. Even if free form common diseases, they may suffer from parasites or toxins. In any such case the abundance and variety of honeyflow, besides proper therapy, is crucial for the maintenance of bee health. Propolis itself cannot be considered as food but can be considered as micro-nutrients for bees. This is due to the fact that some of its compounds may penetrate different bee products, and this way be consumed by bees and their larvae, while stored in the hive. This perspective shows propolis as natural agent reducing the toxicity of pyrethroid acaricides, stimulating production of detoxification enzymes, enhancing the action of antibiotics, and increasing expression of genes that encode proteins responsible for detoxication. The aim of this review is to summarize current data on the possible impact on veterinary public health of the introduction into propolis of residues of pharmacological agents approved in the EU for use in the treatment of bee colonies and their environment.


Subject(s)
Ascomycota , Propolis , Pyrethrins , Animals , Beekeeping , Larva , Propolis/pharmacology
16.
J Neuroinflammation ; 18(1): 165, 2021 Jul 26.
Article in English | MEDLINE | ID: mdl-34311746

ABSTRACT

BACKGROUND: Malignant glioma, especially glioblastoma, is a highly aggressive disease with a dismal prognosis. Vacuole membrane protein 1 (VMP1) is a critical autophagy-associated protein with roles in oncogenesis and tumor progression. However, the contribution of VMP1 to glioma development as well as its prognostic value has not been established. METHODS: The expression of VMP1 and clinicopathologic data for 1996 glioma samples were collected from authoritative public databases to explore its prognostic value. Lentiviral CRISPR-Cas9 gene editing system was performed to deplete VMP1 expression. Apoptosis assays, cell cycle assays, colony formation assays, and EdU incorporation analysis were conducted to validate the biological function of VMP1. Transmission electron microscopy was used to determine the role of VMP1 in regulating autophagy. RESULTS: VMP1 overexpression was associated with advanced disease and had a poor prognosis in patients with glioma. The depletion of VMP1 by CRISPR-Cas9 gene editing significantly inhibited cell proliferation, increased cell death, and induced cell cycle arrest. Mechanistically, VMP1 knockout blocked autophagic flux and thus sensitized glioma cells to radiotherapy and chemotherapy. Moreover, a nomogram model showed that VMP1 expression has high prognostic value for determining survival in glioma. CONCLUSIONS: Our results provide insights into the pathological and biological functions of VMP1, including its roles in promoting tumor growth and progression, and support its value as a new diagnostic and prognostic biomarker for glioma.


Subject(s)
Autophagy , Glioma/metabolism , Glioma/pathology , Membrane Proteins/metabolism , Apoptosis , Autophagy/genetics , Biomarkers , Cell Cycle , Cell Line, Tumor , Cell Proliferation , Gene Editing/methods , Humans , Membrane Proteins/genetics , Microscopy, Electron, Transmission , Neoplasm Staging , Prognosis
17.
Traffic ; 19(8): 624-638, 2018 08.
Article in English | MEDLINE | ID: mdl-29761602

ABSTRACT

The multispanning membrane protein vacuole membrane protein 1 (VMP1) marks and regulates endoplasmic reticulum (ER)-domains associated with diverse ER-organelle membrane contact sites. A proportion of these domains associate with endosomes during their maturation and remodeling. We found that these VMP1 domains are enriched in choline/ethanolamine phosphotransferase and phosphatidylinositol synthase (PIS1), 2 ER enzymes required for the synthesis of various phospholipids. Interestingly, the lack of VMP1 impairs the formation of PIS1-enriched ER domains, suggesting a role in the distribution of phosphoinositides. In fact, depletion of VMP1 alters the distribution of PtdIns4P and proteins involved in the trafficking of PtdIns4P. Consistently, in these conditions, defects were observed in endosome trafficking and maturation as well as in Golgi morphology. We propose that VMP1 regulates the formation of ER domains enriched in lipid synthesizing enzymes. These domains might be necessary for efficient distribution of PtdIns4P and perhaps other lipid species. These findings, along with previous reports that involved VMP1 in regulating PtdIns3P during autophagy, expand the role of VMP1 in lipid trafficking and explain the pleiotropic effects observed in VMP1-deficient mammalian cells and other model systems.


Subject(s)
CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase/metabolism , Endoplasmic Reticulum/metabolism , Membrane Proteins/metabolism , Phosphatidylinositols/metabolism , Vacuoles/metabolism , Animals , Autophagy/physiology , COS Cells , Cell Line , Cell Line, Tumor , Chlorocebus aethiops , Endosomes/metabolism , Golgi Apparatus/metabolism , HeLa Cells , Humans , Phosphatidylinositol Phosphates/metabolism , Protein Transport/physiology
18.
J Biomed Sci ; 27(1): 97, 2020 Oct 22.
Article in English | MEDLINE | ID: mdl-33087127

ABSTRACT

Autophagy is a process in which a myriad membrane structures called autophagosomes are formed de novo in a single cell, which deliver the engulfed substrates into lysosomes for degradation. The size of the autophagosomes is relatively uniform in non-selective autophagy and variable in selective autophagy. It has been recently established that autophagosome formation occurs near the endoplasmic reticulum (ER). In this review, we have discussed recent advances in the relationship between autophagosome formation and endoplasmic reticulum. Autophagosome formation occurs near the ER subdomain enriched with phospholipid synthesizing enzymes like phosphatidylinositol synthase (PIS)/CDP-diacylglycerol-inositol 3-phosphatidyltransferase (CDIPT) and choline/ethanolamine phosphotransferase 1 (CEPT1). Autophagy-related protein 2 (Atg2), which is involved in autophagosome formation has a lipid transfer capacity and is proposed to directly transfer the lipid molecules from the ER to form autophagosomes. Vacuole membrane protein 1 (VMP1) and transmembrane protein 41b (TMEM41b) are ER membrane proteins that are associated with the formation of the subdomain. Recently, we have reported that an uncharacterized ER membrane protein possessing the DNAJ domain, called ERdj8/DNAJC16, is associated with the regulation of the size of autophagosomes. The localization of ERdj8/DNAJC16 partially overlaps with the PIS-enriched ER subdomain, thereby implying its association with autophagosome size determination.


Subject(s)
Autophagosomes/metabolism , Endoplasmic Reticulum/metabolism , Animals , Autophagy , Autophagy-Related Proteins/metabolism , Humans
19.
Sensors (Basel) ; 20(21)2020 Nov 05.
Article in English | MEDLINE | ID: mdl-33167525

ABSTRACT

Localization estimation and clock synchronization are important research directions in the application of wireless sensor networks. Aiming at the problems of low positioning accuracy and slow convergence speed in localization estimation methods based on message passing, this paper proposes a low-complexity distributed cooperative joint estimation method suitable for dynamic networks called multi-Gaussian variational message passing (M-VMP). The proposed method constrains the message to be a multi-Gaussian function superposition form to reduce the information loss in the variational message passing algorithm (VMP). Only the mean, covariance and weight of each message need to be transmitted in the network, which reduces the computational complexity while ensuring the information completeness. The simulation results show that the proposed method is superior to the VMP algorithm in terms of position accuracy and convergence speed and is close to the sum-product algorithm over a wireless network (SPAWN) based on non-parametric belief propagation, but the computational complexity and communication load are significantly reduced.

20.
Ann Hematol ; 98(12): 2805-2814, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31620815

ABSTRACT

In the ALCYONE trial, daratumumab plus bortezomib, melphalan, and prednisone (D-VMP) reduced the risk of disease progression or death by 50% versus bortezomib, melphalan, and prednisone (VMP) in patients with transplant-ineligible newly diagnosed multiple myeloma. Here, we report a subanalysis of East Asian patients from ALCYONE. After a median follow-up of 17.1 and 15.9 months for Japanese (n = 50) and Korean (n = 41) patients, respectively, median progression-free survival for D-VMP versus VMP was not reached (NR) versus 20.7 months in Japanese patients and NR versus 14.0 months in Korean patients. The overall response rate for D-VMP versus VMP was 96% versus 92% in Japanese patients and 91% versus 61% in Korean patients. Using next-generation sequencing, minimal residual disease negativity at 10-5 sensitivity for D-VMP versus VMP was 33% versus 8% among Japanese patients and 17% versus 0% among Korean patients. Rates of any grade and grade 3/4 pneumonia were consistent with the rates observed for the global safety population. Similar efficacy and safety findings were observed in the combined Japanese and Korean subgroup and ≥ 75 years of age subgroup. In conclusion, D-VMP was safe and efficacious in East Asian patients, consistent with the global ALCYONE population.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Multiple Myeloma/drug therapy , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Bortezomib/administration & dosage , Bortezomib/adverse effects , Disease-Free Survival , Asia, Eastern/epidemiology , Female , Humans , Male , Melphalan/administration & dosage , Melphalan/adverse effects , Middle Aged , Multiple Myeloma/mortality , Prednisolone/administration & dosage , Prednisolone/adverse effects , Survival Rate
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