scholarly journals SMN protein promotes membrane compartmentalization of ribosomal protein S6 transcript in human fibroblasts

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Francesca Gabanella ◽  
Annalisa Onori ◽  
Massimo Ralli ◽  
Antonio Greco ◽  
Claudio Passananti ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Ribosome Biogenesis ◽  
Potential Role ◽  
Muscular Atrophy ◽  
Human Fibroblasts ◽  
Membrane Dynamics ◽  
Translation Efficiency ◽  
Dependent Manner ◽  
Smn Protein

Abstract Alterations of RNA homeostasis can lead to severe pathological conditions. The Survival of Motor Neuron (SMN) protein, which is reduced in Spinal Muscular Atrophy, impacts critical aspects of the RNA life cycle, such as splicing, trafficking, and translation. Increasing evidence points to a potential role of SMN in ribosome biogenesis. Our previous study revealed that SMN promotes membrane-bound ribosomal proteins (RPs), sustaining activity-dependent local translation. Here, we suggest that plasma membrane domains could be a docking site not only for RPs but also for their encoding transcripts. We have shown that SMN knockdown perturbs subcellular localization as well as translation efficiency of RPS6 mRNA. We have also shown that plasma membrane-enriched fractions from human fibroblasts retain RPS6 transcripts in an SMN-dependent manner. Furthermore, we revealed that SMN traffics with RPS6 mRNA promoting its association with caveolin-1, a key component of membrane dynamics. Overall, these findings further support the SMN-mediated crosstalk between plasma membrane dynamics and translation machinery. Importantly, our study points to a potential role of SMN in the ribosome assembly pathway by selective RPs synthesis/localization in both space and time.

scholarly journals The action of α-adrenergic agonists on plasma-membrane calcium fluxes in perfused rat liver

1984 ◽  
Vol 220 (1) ◽  
pp. 43-50 ◽  
Author(s):  
P H Reinhart ◽  
W M Taylor ◽  
F L Bygrave
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Potential Role ◽  
Dependent Manner ◽  
Perfused Rat Liver ◽  
Adrenergic Agonists ◽  
Mediated Effects ◽  
Alpha Agonist ◽  
Alpha Adrenergic Agonist

The effect of alpha-adrenergic agonists on Ca2+ fluxes was examined in the perfused rat liver by using a combination of Ca2+-electrode and 45Ca2+-uptake techniques. We showed that net Ca2+ fluxes can be described by the activities of separate Ca2+-uptake and Ca2+-efflux components, and that alpha-adrenergic agonists modulate the activity of both components in a time-dependent manner. Under resting conditions, Ca2+-uptake and -efflux activities are balanced, resulting in Ca2+ cycling across the plasma membrane. The alpha-adrenergic agonists vasopressin and angiotensin, but not glucagon, stimulate the rate of both Ca2+ efflux and Ca2+ uptake. During the first 2-3 min of alpha-agonist administration the effect on the efflux component is the greater, the net effect being efflux of Ca2+ from the cell. After 3-4 min of phenylephrine treatment, net Ca2+ movements are essentially complete, however, the rate of Ca2+ cycling is significantly increased. After removal of the alpha-agonist a large stimulation of the rate of Ca2+ uptake leads to the net accumulation of Ca2+ by the cell. The potential role of these Ca2+ flux changes in the expression of alpha-adrenergic-agonist-mediated effects is discussed.

Cloning and expression of two plasma membrane aquaporins expressed during the ripening of grape berry

2003 ◽  
Vol 30 (6) ◽  
pp. 621 ◽  
Author(s):  
Sarah Picaud ◽  
Frédéric Becq ◽  
Fabienne Dédaldéchamp ◽  
Agnès Ageorges ◽  
Serge Delrot
Keyword(s):  
Plasma Membrane ◽  
Xenopus Oocytes ◽  
Potential Role ◽  
Grape Berry ◽  
Cloning And Expression ◽  
Vitis Vinifera L ◽  
Moderate Increase ◽  
Grape Berries ◽  
Urea Uptake

The ripening of grape (Vitis vinifera L.) berry is accompanied by dramatic accumulation of sugars and water. Two full-length clones and several partial clones encoding plasma membrane aquaporins (PIP) were cloned from grape berries collected at the beginning of ripening. Based on their sequences, on a phylogenetic analysis and on functional properties, both clones, called VvPIP1a and VvPIP1b were assigned to the PIP1 subfamily. RNA gel blot studies with berries at various stages of development indicated that VvPIP expression was highest at stages following veraison. Injection of Xenopus oocytes with VvPIP1a cRNA induced a moderate increase of water permeability and a large increase in glycerol permeability, whereas injection with VvPIP1b cRNA did not affect these permeabilities. Injection of VvPIP1a cRNA, but not VvPIP1b cRNA, inhibited urea uptake by the oocyte, and this inhibition was sensitive to HgCl2. The data are discussed in relation with the potential role of aquaporins in fruit physiology.

scholarly journals Quorum-sensing regulation in rhizobia and its role in symbiotic interactions with legumes

2007 ◽  
Vol 362 (1483) ◽  
pp. 1149-1163 ◽  
Author(s):  
Maria Sanchez-Contreras ◽  
Wolfgang D Bauer ◽  
Mengsheng Gao ◽  
Jayne B Robinson ◽  
J Allan Downie
Keyword(s):  
Quorum Sensing ◽  
Potential Role ◽  
Active Role ◽  
Dependent Manner ◽  
Homoserine Lactones ◽  
Signalling Molecules ◽  
Sensing Systems ◽  
Symbiotic Interactions ◽  
Regulatory Systems

Legume-nodulating bacteria (rhizobia) usually produce N -acyl homoserine lactones, which regulate the induction of gene expression in a quorum-sensing (or population-density)-dependent manner. There is significant diversity in the types of quorum-sensing regulatory systems that are present in different rhizobia and no two independent isolates worked on in detail have the same complement of quorum-sensing genes. The genes regulated by quorum sensing appear to be rather diverse and many are associated with adaptive aspects of physiology that are probably important in the rhizosphere. It is evident that some aspects of rhizobial physiology related to the interaction between rhizobia and legumes are influenced by quorum sensing. However, it also appears that the legumes play an active role, both in terms of interfering with the rhizobial quorum-sensing systems and responding to the signalling molecules made by the bacteria. In this article, we review the diversity of quorum-sensing regulation in rhizobia and the potential role of legumes in influencing and responding to this signalling system.

scholarly journals Contact inhibition of growth of human diploid fibroblasts by immobilized plasma membrane glycoproteins.

1986 ◽  
Vol 103 (2) ◽  
pp. 361-367 ◽  
Author(s):  
R J Wieser ◽  
F Oesch
Keyword(s):  
Plasma Membrane ◽  
Cell Density ◽  
High Cell Density ◽  
Human Fibroblasts ◽  
Dependent Manner ◽  
High Cell ◽  
Membrane Glycoproteins ◽  
Type Iii ◽  
Inhibition Of Growth ◽  
Terminal Galactose

The human embryonic fibroblasts used in this study show pronounced inhibition of growth when reaching a critical cell density. High cell density and growth inhibition has previously been mimicked by the addition of glutaraldehyde-fixed cells or of isolated plasma membranes to sparsely seeded proliferating fibroblasts (Wieser, R. J., R. Heck, and F. Oesch, 1985, Exp. Cell Res., 158:493-499). In this report, we describe the successful solubilization of the growth-inhibiting glycoproteins and their covalent coupling to silicabeads (10 microns), which had been derivatized with 3-isothiocyanatopropyltriethoxysilane. The beads, bearing the plasma membrane proteins, were added to sparsely seeded, actively proliferating fibroblasts, and growth was measured by the determination of cell number or of incorporation of [3H]thymidine into DNA. The growth was inhibited in a concentration-dependent manner, whereby 50% inhibition was achieved with 0.3 micrograms of immobilized protein added to 5 X 10(3) cells. Terminal galactose residues of plasma membrane glycoproteins with N-glycosydically bound carbohydrates were responsible for the inhibition of growth. Dense cultures of human fibroblasts are characterized by an accelerated synthesis of procollagen type III. We have found that this cellular response can also be induced by the addition of immobilized plasma membrane glycoproteins to sparsely seeded cells. These observations support the conclusion that the addition of immobilized plasma membrane glycoproteins to sparsely seeded fibroblasts mimics the situation occurring at high cell density. These results show that cell-cell contacts via plasma membrane glycoproteins carrying terminal galactose residues are important for the regulation of the proliferation of cultured human fibroblasts and presumably of the accelerated synthesis of collagen type III.

scholarly journals Regulation of the electrogenic H+ channel in the plasma membrane of neutrophils: possible role of phospholipase A2, internal and external protons

1993 ◽  
Vol 292 (2) ◽  
pp. 445-450 ◽  
Author(s):  
A Kapus ◽  
K Suszták ◽  
E Ligeti
Keyword(s):  
Plasma Membrane ◽  
Phospholipase A2 ◽  
Neutrophil Granulocytes ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Conducting Pathway ◽  
External Ph ◽  
Force Relationship ◽  
Stimulation Of

Possible factors regulating the opening of and the rate of H+ flux through a recently described, Cd(2+)-sensitive, phorbol ester- and arachidonic acid (AA)-activatable H(+)-conducting pathway in the plasma membrane of neutrophil granulocytes were investigated. (1) The phospholipase A2 blocker p-bromophenacyl bromide (BPB) inhibited the phorbol 12-myristate 13-acetate (PMA)-induced activation of this channel in a concentration-dependent manner (IC50, 4 microM). (2) Neither BPB nor the protein kinase C (PKC) inhibitor staurosporine influenced the AA-elicited stimulation of this route. (3) Intracellular acidification (cytoplasmic pH below 6.9) itself is capable of activating an electrogenic, Cd(2+)-sensitive H+ efflux indicating that protons can open up this route in the absence of any other stimulator. (4) PMA significantly decreases the intracellular H+ concentration ([H+]i) threshold for the opening of the channel, thus providing a conductive state at resting pH values, and elevates the rate of H+ efflux at any [H+]i. (5) Changes in external pH also modify the operation of the channel: above an extracellular pH (pH(o)) value of 7.4, the H(+)-flux/driving force relationship is approx. 5-fold greater than below this value. Our results suggest a multifactorial regulation of the electrogenic H+ channel: most probably PKC activates the channel indirectly, via stimulation of phospholipase A2 that subsequently liberates AA. In addition to this, the channel conductance seems to be promoted by internal H+ and inhibited by external H+.

scholarly journals Palmitoylation-dependent Estrogen Receptor α Membrane Localization: Regulation by 17β-Estradiol

2005 ◽  
Vol 16 (1) ◽  
pp. 231-237 ◽  
Author(s):  
Filippo Acconcia ◽  
Paolo Ascenzi ◽  
Alessio Bocedi ◽  
Enzo Spisni ◽  
Vittorio Tomasi ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Estrogen Receptor ◽  
Plasma Membrane ◽  
Estrogen Receptor Α ◽  
Membrane Localization ◽  
Target Cells ◽  
Dependent Manner ◽  
Caveolin 1 ◽  
17Β Estradiol

A fraction of the nuclear estrogen receptor α (ERα) is localized to the plasma membrane region of 17β-estradiol (E2) target cells. We previously reported that ERα is a palmitoylated protein. To gain insight into the molecular mechanism of ERα residence at the plasma membrane, we tested both the role of palmitoylation and the impact of E2 stimulation on ERα membrane localization. The cancer cell lines expressing transfected or endogenous human ERα (HeLa and HepG2, respectively) or the ERα nonpalmitoylable Cys447Ala mutant transfected in HeLa cells were used as experimental models. We found that palmitoylation of ERα enacts ERα association with the plasma membrane, interaction with the membrane protein caveolin-1, and nongenomic activities, including activation of signaling pathways and cell proliferation (i.e., ERK and AKT activation, cyclin D1 promoter activity, DNA synthesis). Moreover, E2 reduces both ERα palmitoylation and its interaction with caveolin-1, in a time- and dose-dependent manner. These data point to the physiological role of ERα palmitoylation in the receptor localization to the cell membrane and in the regulation of the E2-induced cell proliferation.

scholarly journals tRNA Synthetases Are Recruited to Yeast Ribosomes by rRNA Expansion Segment 7L but Do Not Require Association for Functionality

2021 ◽  
Vol 7 (4) ◽  
pp. 73
Author(s):  
Nina Krauer ◽  
Robert Rauscher ◽  
Norbert Polacek
Keyword(s):  
Ribosome Biogenesis ◽  
Protein Biosynthesis ◽  
Ribosomal Subunit ◽  
Trna Synthetase ◽  
Translation Efficiency ◽  
Functional Roles ◽  
Trna Synthetases ◽  
Yeast Ribosomes ◽  
Ribosome Association

Protein biosynthesis is essential for any organism, yet how this process is regulated is not fully understood at the molecular level. During evolution, ribosomal RNA expanded in specific regions, referred to as rRNA expansion segments (ES). First functional roles of these expansions have only recently been discovered. Here we address the role of ES7La located in the large ribosomal subunit for factor recruitment to the yeast ribosome and the potential consequences for translation. Truncation of ES7La has only minor effects on ribosome biogenesis, translation efficiency and cell doubling. Using yeast rRNA deletion strains coupled with ribosome-specific mass spectrometry we analyzed the interactome of ribosomes lacking ES7La. Three aminoacyl-tRNA synthetases showed reduced ribosome association. Synthetase activities however remained unaltered suggesting that the pool of aminoacylated tRNAs is unaffected by the ES deletion. These results demonstrated that aminoacylation activities of tRNA synthetases per se do not rely on ribosome association. These findings suggest a role of ribosome-associated aminoacyl-tRNA synthetase beyond their core enzymatic functions.

Ezrin has properties to self-associate at the plasma membrane

1994 ◽  
Vol 107 (9) ◽  
pp. 2509-2521 ◽  
Author(s):  
C. Andreoli ◽  
M. Martin ◽  
R. Le Borgne ◽  
H. Reggio ◽  
P. Mangeat
Keyword(s):  
Plasma Membrane ◽  
Recombinant Baculovirus ◽  
Dependent Manner ◽  
Physiological Properties ◽  
Self Association ◽  
A Site ◽  
Apical Membranes ◽  
Gastric Parietal Cells ◽  
Overlay Assay

Ezrin, a member of a family of proteins involved in the interaction of the microfilament cytoskeleton with the plasma membrane, plays a role in membrane translocation in gastric parietal cells (Hanzel, D., Reggio, H., Bretscher, A., Forte, J. G. and Mangeat, P. (1991). EMBO J. 10, 2363–2373). Human ezrin was expressed in and purified from Escherichia coli. It possesses all the major biophysical, immunological and physiological properties of natural ezrin. Upon microinjection in live gastric HGT-1 cells, ezrin was incorporated into the dorsal microvilli, a site where the endogeneous protein is localized. By coimmunoprecipitation and ezrin-affinity assays, two HGT-1 cell proteins of 77 and 72 kDa behaved as ezrin-binding proteins. In enriched gastric apical membranes, 125I-ezrin labelled proteins of 80, 77 and 72 kDa by overlay assay. The 80 kDa protein was identified as ezrin and the 77 and 72 kDa proteins as gastric forms of proteins structurally related to ezrin, such as radixin and moesin. In insect cells infected with a recombinant baculovirus, one-third of over-expressed ezrin accumulated at the plasma membrane. Ezrin bound a 77 kDa endogenous peripheral membrane protein, behaving as an insect counterpart of the mammalian ezrin family. In addition to the respective role of the amino- and carboxyl-terminal domains of ezrin in linking the membrane and the cytoskeleton (Algrain, M., Turunen, O., Vaheri, A., Louvard, D. and Arpin, M. (1993). J. Cell Biol. 120, 129–139), both domains interacted synergistically in a salt-dependent manner to trigger self-association of ezrin. Ezrin's self-association properties could represent another way of regulating the number of ezrin molecules bound at specific membrane sites.

Differential Role of PKC Isoforms in GnRH and Phorbol 12-Myristate 13-Acetate Activation of Extracellular Signal-Regulated Kinase and Jun N-Terminal Kinase

Endocrinology ◽  
2010 ◽  
Vol 151 (10) ◽  
pp. 4894-4907 ◽  
Author(s):  
Masha Dobkin-Bekman ◽  
Liat Rahamim Ben-Navi ◽  
Boris Shterntal ◽  
Ludmila Sviridonov ◽  
Fiorenza Przedecki ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fluorescent Protein ◽  
Preliminary Evidence ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Pkc Isoforms ◽  
Green Fluorescent ◽  
Jnk Activation ◽  
Erk2 Activation

GnRH is the first key hormone of reproduction. The role of protein kinase C (PKC) isoforms in GnRH-stimulated MAPK [ERK and Jun N-terminal kinase (JNK)] was examined in the αT3-1 and LβT2 gonadotrope cells. Incubation of the cells with GnRH resulted in a protracted activation of ERK1/2 and a slower and more transient activation of JNK1/2. Gonadotropes express conventional PKCα and conventional PKCβII, novel PKCδ, novel PKCε, and novel PKCθ, and atypical PKC-ι/λ. The use of green fluorescent protein-PKC constructs revealed that GnRH induced rapid translocation of PKCα and PKCβII to the plasma membrane, followed by their redistribution to the cytosol. PKCδ and PKCε localized to the cytoplasm and Golgi, followed by the rapid redistribution by GnRH of PKCδ to the perinuclear zone and of PKCε to the plasma membrane. Interestingly, PKCα, PKCβII, and PKCε translocation to the plasma membrane was more pronounced and more prolonged in phorbol-12-myristate-13-acetate (PMA) than in GnRH-treated cells. The use of selective inhibitors and dominant-negative plasmids for the various PKCs has revealed that PKCβII, PKCδ, and PKCε mediate ERK2 activation by GnRH, whereas PKCα, PKCβII, PKCδ, and PKCε mediate ERK2 activation by PMA. Also, PKCα, PKCβII, PKCδ, and PKCε are involved in GnRH and PMA stimulation of JNK1 in a cell-context-dependent manner. We present preliminary evidence that persistent vs. transient redistribution of selected PKCs or redistribution of a given PKC to the perinuclear zone vs. the plasma membrane may dictate its selective role in ERK or JNK activation. Thus, we have described the contribution of selective PKCs to ERK and JNK activation by GnRH.

Postsynaptic nanodomains generated by local palmitoylation cycles

2015 ◽  
Vol 43 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Masaki Fukata ◽  
Atsushi Sekiya ◽  
Tatsuro Murakami ◽  
Norihiko Yokoi ◽  
Yuko Fukata
Keyword(s):  
Plasma Membrane ◽  
Protein Targeting ◽  
Scaffolding Protein ◽  
Dependent Manner ◽  
Membrane Domains ◽  
Post Translational Modification ◽  
Cellular Functions ◽  
Protein Palmitoylation ◽  
Specific Proteins

Precise regulation of protein assembly at specialized membrane domains is essential for diverse cellular functions including synaptic transmission. However, it is incompletely understood how protein clustering at the plasma membrane is initiated, maintained and controlled. Protein palmitoylation, a common post-translational modification, regulates protein targeting to the plasma membrane. Such modified proteins are enriched in these specialized membrane domains. In this review, we focus on palmitoylation of PSD-95, which is a major postsynaptic scaffolding protein and makes discrete postsynaptic nanodomains in a palmitoylation-dependent manner and discuss a determinant role of local palmitoylation cycles in creating highly localized hotspots at the membrane where specific proteins concentrate to organize functional domains.

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