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Membrane fusion

Jeannette Attiger, Alois Boos, Karl Klisch
Binucleate trophoblast giant cells (TGCs) are one characteristic feature of the ruminant placenta. In cows, the frequency of TGCs remains constant for most of the duration of pregnancy. As TGCs are depleted by their fusion with uterine epithelial cells, they need to be constantly formed. It is still unclear whether they develop from stem cells within the trophectoderm or whether they can arise from any uninucleate trophoblast cell (UTC). Within the latter, generally accepted theory, a basally located uninucleate cell (BUC) without contact to the feto-maternal interface would represent a transient cell between a UTC and a TGC...
June 20, 2018: Cells, Tissues, Organs
Qinle Ba, Guruprasad Raghavan, Kirill Kiselyov, Ge Yang
In eukaryotic cells, lysosomes are distributed in the cytoplasm as individual membrane-bound compartments to degrade macromolecules and to control cellular metabolism. A fundamental yet unanswered question is whether and, if so, how individual lysosomes are organized spatially to coordinate and integrate their functions. To address this question, we analyzed their collective behavior in cultured cells using spatial statistical techniques. We found that in single cells, lysosomes maintain non-random, stable, yet distinct spatial distributions mediated by the cytoskeleton, the endoplasmic reticulum (ER), and lysosomal biogenesis...
June 19, 2018: Cell Reports
Michael P Triebwasser, Xiaobo Wu, Paula Bertram, Dennis E Hourcade, Donald Michael Nelson, John P Atkinson
PROBLEM: Crry is a widely expressed type 1 transmembrane complement regulatory protein in rodents which protects self-tissue by downregulating C3 activation. Crry-/- concepti produced by Crry+/-  × Crry+/- matings are attacked by maternal complement system leading to loss before day 10. The membrane attack complex is not the mediator of this death. We hypothesized that the ability of C3b to engage the alternative pathway's feedback loop relatively unchecked on placental membranes induces the lesion yielding the demise of the Crry-/- mouse...
June 20, 2018: American Journal of Reproductive Immunology: AJRI
Abhijit Chowdhury, Teru Ogura, Masatoshi Esaki
Mitochondria continuously undergo coordinated fusion and fission during vegetative growth to keep their homogeneity and to remove damaged components. A cytosolic AAA ATPase, Cdc48, is implicated in the mitochondrial fusion event and turnover of a fusion-responsible GTPase in the mitochondrial outer membrane, Fzo1, suggesting a possible linkage of mitochondrial fusion and Fzo1 turnover. Here, we identified two Cdc48 cofactor proteins, Ubp3 and Ubx2, involving mitochondria regulation. In the absence of UBP3, mitochondrial fragmentation and aggregation were observed...
June 19, 2018: Journal of Biochemistry
M Shettar, R Karkal, R Misra, A Kakunje, V V Mohan Chandran, R D Mendonsa
Arachnoid cysts are benign space-occupying brain lesions that contain cerebrospinal fluid. Most cases are congenital in origin, caused by failed fusion of the arachnoid membrane early in fetal development. Cases are often incidentally detected on neuroimaging; however, rarely patients present with neuropsychiatric manifestations when cysts expand and cause a midline shift, compression of nearby brain tissue or cerebrospinal fluid compartments or both. We report a case of a 56-year-old woman with no past history or family history of psychiatric illness who developed acute-onset right-sided weakness, depressive symptoms, and other neuropsychiatric deficits...
June 2018: East Asian Archives of Psychiatry: Official Journal of the Hong Kong College of Psychiatrists
Julia Pfanzelter, Serge Mostowy, Michael Way
Septins are conserved components of the cytoskeleton that play important roles in many fundamental cellular processes including division, migration, and membrane trafficking. Septins can also inhibit bacterial infection by forming cage-like structures around pathogens such as Shigella We found that septins are recruited to vaccinia virus immediately after its fusion with the plasma membrane during viral egress. RNA interference-mediated depletion of septins increases virus release and cell-to-cell spread, as well as actin tail formation...
June 19, 2018: Journal of Cell Biology
C Zhao, A Y-H Wu, X Yu, Y Gu, Y Lu, X Song, N An, Y Zhang
Airway remodeling manifested by hyperplasia of airway smooth muscle cells (ASMCs) and other structural and functional changes is a pathological condition in asthma not addressed by current treatment. Ca2+ signaling is crucial for ASMC proliferation. Inositol-1,4,5-trisphosphate receptor (IP3R) and ryanodine receptor (RyR) mediate Ca2+ release from endoplasmic reticulum/sarcoplasmic reticulum (ER/SR). Upon sensing the depletion of Ca2+ in ER/SR, stromal interaction molecule 1 (STIM1) aggregates and redistributes at the microdomain of ER/SR-plasma membrane (PM) and activates Orai1, a component of the store-operated Ca2+ (SOC) channels, to initiate Ca2+ influx...
April 2018: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
Daniel Kerr, Gregory T Tietjen, Zhiliang Gong, Emad Tajkhorshid, Erin J Adams, Ka Yee C Lee
There is a diverse class of peripheral membrane-binding proteins that specifically bind phosphatidylserine (PS), a lipid that signals apoptosis or cell fusion depending on the membrane context of its presentation. PS-receptors are specialized for particular PS-presenting pathways, indicating that they might be sensitive to the membrane context. In this review, we describe a combination of thermodynamic, structural, and computational techniques that can be used to investigate the mechanisms underlying this sensitivity...
June 16, 2018: Biochimica et Biophysica Acta
Temet M McMichael, Yu Zhang, Adam D Kenney, Lizhi Zhang, Ashley Zani, Mijia Lu, Mahesh Chemudupati, Jianrong Li, Jacob S Yount
Human metapneumovirus (hMPV) utilizes a bifurcated cellular entry strategy, fusing either with the plasma membrane or, after endocytosis, with the endosome membrane. Whether cellular factors restrict or enhance either entry pathway is largely unknown. We found that the interferon-induced transmembrane protein 3 (IFITM3) inhibits hMPV infection to an extent similar to endocytosis-inhibiting drugs, and an IFITM3 variant that accumulates at the plasma membrane in addition to its endosome localization provided increased virus restriction...
June 15, 2018: Journal of Infectious Diseases
Kathleen Delfosse, Michael R Wozny, Kiah A Barton, Neeta Mathur, Nigel Griffiths, Jaideep Mathur
Plastids in the viridiplantae sporadically form thin tubules called stromules that increase the interactive surface between the plastid and the surrounding cytoplasm. Several recent publications that report observations of certain proteins localizing to the extensions have then used the observations to suggest stromule-specific functions. The mechanisms by which specific localizations on these transient and sporadically formed extensions might occur remain unclear. Previous studies have yet to address the spatiotemporal relationship between a particular protein localization pattern and its distribution on an extended stromules and/or the plastid body...
2018: Frontiers in Plant Science
Antonietta Rosella Farina, Lucia Cappabianca, Pierdomenico Ruggeri, Luciana Gneo, Cristina Pellegrini, Maria-Concetta Fargnoli, Andrew Reay Mackay
Oncogenes derived from the neurotrophin receptor tropomyosin-related kinase TrkA act as drivers in sub-populations of a wide-range of human cancers. This, combined with a recent report that both adult and childhood cancers driven by novel oncogenic TrkA chimeric-fusions exhibit profound, long-lived therapeutic responses to the Trk inhibitor Larotrectinib, highlights the need to improve clinical detection of TrkA oncogene-driven cancers in order to maximise this novel therapeutic potential. Cancers potentially driven by TrkA oncogenes include a proportion of paediatric neuroblastomas (NBs) that express the alternative TrkA splice variant TrkAIII, which exhibits exon 6, 7 and 9 skipping and oncogenic-activity that depends upon deletion of the extracellular D4 Ig-like domain...
June 18, 2018: Journal of Experimental & Clinical Cancer Research: CR
Ling Chien, Min-Zong Liang, Chu-Yuan Chang, Chen Wang, Linyi Chen
Due to the inhibitory microenvironment and reduced intrinsic growth capacity of neurons, neuronal regeneration of central nervous system remains challenging. Neurons are highly energy demanding and require sufficient mitochondria to support cellular activities. In response to stimuli, mitochondria undergo fusion/fission cycles to adapt to environment. It is thus logical to hypothesize that the plasticity of mitochondrial dynamics is required for neuronal regeneration. In this study, we examined the role of mitochondrial dynamics during regeneration of rat hippocampal neurons...
June 15, 2018: Biochimica et Biophysica Acta
Clifford M Csizmar, Jacob R Petersburg, Carston R Wagner
The ability to direct targeted intercellular interactions has the potential to enable and expand the use of cell-based therapies for regenerative medicine, tissue engineering, and immunotherapy. While genetic engineering approaches have proven effective, these techniques are not amenable to all cell types and often yield permanent modifications with potentially long-lasting adverse effects, restricting their application. To circumvent these limitations, there is intense interest in developing non-genetic methods to modify cell membranes with functional groups that will enable the recognition of target cells...
May 22, 2018: Cell Chemical Biology
Wei Liu, Xiuying Duan, Xuefei Fang, Weina Shang, Chao Tong
Neurodegeneration is characterized by protein aggregate deposits and mitochondrial malfunction. Reduction in Tom40 (translocase of outer membrane 40) expression, a key subunit of the translocase of the outer mitochondrial membrane complex, led to accumulation of ubiquitin (Ub)-positive protein aggregates engulfed by Atg8a-positive membranes. Other macroautophagy markers were also abnormally accumulated. Autophagy was induced but the majority of autophagosomes failed to fuse with lysosomes when Tom40 was downregulated...
June 18, 2018: Autophagy
Adrian Florea, Andrei Patrick Varga, Horea Vladi Matei
We tested the ability of bee venom (BV), melittin (Mlt), and phospholipase A2 (PLA) - used in 5 concentrations each (5, 10, 15, 20 and 40 μg/100 μl) - to promote ultrastructural changes and reorganization of cristae in vitro in mitochondria isolated from rat adrenal cortex after a protocol optimized by us. Thus, apart from two control grups (CI and CS), in which the mitochondria were suspended into saline buffer and isolation medium respectively, 15 more groups of mitochondria were constituted, corresponding to the five different doses of the three substance tested (BV5 to M40; M5 to M40 and P5 to P40)...
June 9, 2018: Micron: the International Research and Review Journal for Microscopy
Mamiko Tsugane, Hiroaki Suzuki
We assessed the applicability of giant unilamellar vesicles (GUVs) for RNA detection using in vesicle reverse transcription polymerase chain reaction (RT-PCR). We prepared GUVs that encapsulated one-pot RT-PCR reaction mixture including template RNA, primers, and Taqman probe, using water-in-oil emulsion transfer method. After thermal cycling, we analysed the GUVs that exhibited intense fluorescence signals, which represented the cDNA amplification. The detailed analysis of flow cytometry data demonstrated that rRNA and mRNA in the total RNA can be amplified from 10-100 copies in the GUVs with 5-10 μm diameter, although the fraction of reactable GUV was approximately 60% at most...
June 15, 2018: Scientific Reports
H Saari, E Lisitsyna, K Rautaniemi, T Rojalin, L Niemi, O Nivaro, T Laaksonen, M Yliperttula, E Vuorimaa-Laukkanen
In response to physiological and artificial stimuli, cells generate nano-scale extracellular vesicles (EVs) by encapsulating biomolecules in plasma membrane-derived phospholipid envelopes. These vesicles are released to bodily fluids, hence acting as powerful endogenous mediators in intercellular signaling. EVs provide a compelling alternative for biomarker discovery and targeted drug delivery, but their kinetics and dynamics while interacting with living cells are poorly understood. Here we introduce a novel method, fluorescence lifetime imaging microscopy (FLIM) to investigate these interaction attributes...
June 12, 2018: Journal of Controlled Release: Official Journal of the Controlled Release Society
Hao Sun, Yaoke Duan, Xiaocui Qi, Liyang Zhang, Heqiang Huo, Haijun Gong
Background and Aims: Silicon has been proven to exert beneficial effects on plant growth and stress tolerance, and silicon accumulation varies among different plant species. Cucumber (Cucumis sativus) is a widely used dicot model for silicon accumulation, but little is known about the molecular mechanism of its silicon uptake. Previously, we isolated and characterized CsLsi1, a silicon influx transporter gene from cucumber. In this study, we cloned a putative silicon efflux transporter gene, CsLsi2, from cucumber and investigated its role in silicon uptake...
June 14, 2018: Annals of Botany
Satyan Sharma, Manfred Lindau
Neurotransmitter release occurs in the form of quantal events by fusion of secretory vesicles with the plasma membrane, and begins with the formation of a fusion pore that has a conductance similar to that of a large ion channel or gap junction. In this review we propose mechanisms of fusion pore formation and discuss their implications for fusion pore structure and function. Accumulating evidence indicates a direct role of SNARE proteins in the opening of fusion pores. Fusion pores are likely neither protein channels nor purely lipid, but are of proteolipidic composition...
June 14, 2018: FEBS Letters
Yineng Han, Lingfei Jia, Yunfei Zheng, Weiran Li
Saliva, which contains biological information, is considered a valuable diagnostic tool for local and systemic diseases and conditions because, similar to blood, it contains important molecules like DNA, RNA, and proteins. Exosomes are cell-derived vesicles 30-100 nm in diameter with substantial biological functions, including intracellular communication and signalling. These vesicles, which are present in bodily fluids, including saliva, are released upon fusion of multivesicular bodies (MVBs) with the cellular plasma membrane...
2018: International Journal of Biological Sciences
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