scholarly journals Arabidopsis ADR1 helper NLR immune receptors localize and function at the plasma membrane in a phospholipid dependent manner

2021 ◽  
Author(s):  
Svenja C. Saile ◽  
Frank M. Ackermann ◽  
Sruthi Sunil ◽  
Jutta Keicher ◽  
Adam Bayless ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Dependent Manner ◽  
Immune Receptors ◽  
And Function

MUNC13 REGULATES SECRETION AT THE GOLGI IN A LOCALIZATION-DEPENDENT MANNER

2008 ◽  
Vol 31 (4) ◽  
pp. 11
Author(s):  
Neil M Goldenberg ◽  
Mel Silverman
Keyword(s):  
Plasma Membrane ◽  
Secretory Pathway ◽  
Phorbol Esters ◽  
Cell Structure ◽  
Eukaryotic Cell ◽  
Temperature Sensitive ◽  
Dependent Manner ◽  
C1 Domain ◽  
Surface Labelling ◽  
And Function

Background: Constitutive secretion is critical for the maintenance of eukaryotic cell structure and function. Our lab has shown that Rab34 is required for secretion at the Golgi^1, and that the C1 domain-containing protein, Munc13, is an effector of Rab34^2. Current studies seek to elucidate potential roles for Munc13in secretion at the Golgi. Methods: Using a temperature-sensitive mutant of the Vesicular Stomatitis G-protein fused to GFP (VSVG-GFP) to monitor secretion, we examinedthe role of Munc13 in secretion in HeLa cells. Cells transfected with VSVG-GFP were treated with Munc13, amutant lacking the C1 domain (C1-less), and the phorbol esters TPA andPDBu. The rate of VSVG-GFP secretion was monitored using surface labelling of plasmalemmal VSVG-GFP and spinning disc confocal microscopy. Results: TPA treatment resulted in an increase in the rate of VSVG-GFP appearance at the plasma membrane. Co-transfection of either Munc13 or C1-less alone also resulted in an increased rate of VSVG-GFP transport. Transfection of Munc13 plus TPA treatment resulted in amarked decrease in the rate of VSVG-GFP transport. Since TPA treatment relocalizes Munc13 to the plasma membrane, this result suggests that the availability of Munc13 in the cytosol is required for its effect on VSVG-GFP secretion. Conclusions: Munc13 over-expression increases the rate of VSVG-GFP secretion to the plasma membrane. Sequestration of Munc13 at the plasma membrane with TPA abrogates thiseffect, and reduces the rate of VSVG-GFP secretion. We propose that Munc13 effects VSVG-GFP secretion via its interaction with Rab34 at the Golgi. References: 1. Goldenberg, NM, S. Grinstein, M. Silverman. Golgi-bound Rab34 is a Novel Member ofthe Secretory Pathway. Mol BiolCell. 18(12):4762-4771 (2007). 2. Speight, P, M. Silverman.Diacylglycerol-Activated Hmunc13 Serves as an Effector of the GTPaseRab34. Traffic.6(10):858-865 (2005).

scholarly journals Rab11-dependent recycling of calcium channels is mediated by auxiliary subunit α2δ-1 but not α2δ-3

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James O. Meyer ◽  
Annette C. Dolphin
Keyword(s):  
Plasma Membrane ◽  
Calcium Channels ◽  
Dominant Negative ◽  
Calcium Currents ◽  
Dependent Manner ◽  
Auxiliary Subunit ◽  
Voltage Gated Calcium Channels ◽  
Endosomal Recycling ◽  
Recycling Pathway ◽  
And Function

AbstractN-type voltage-gated calcium channels (CaV2.2) are predominantly expressed at presynaptic terminals, and their function is regulated by auxiliary α2δ and β subunits. All four mammalian α2δ subunits enhance calcium currents through CaV1 and CaV2 channels, and this increase is attributed, in part, to increased CaV expression at the plasma membrane. In the present study we provide evidence that α2δ-1, like α2δ-2, is recycled to the plasma membrane through a Rab11a-dependent endosomal recycling pathway. Using a dominant-negative Rab11a mutant, Rab11a(S25N), we show that α2δ-1 increases plasma membrane CaV2.2 expression by increasing the rate and extent of net forward CaV2.2 trafficking in a Rab11a-dependent manner. Dominant-negative Rab11a also reduces the ability of α2δ-1 to increase CaV2.2 expression on the cell-surface of hippocampal neurites. In contrast, α2δ-3 does not enhance rapid forward CaV2.2 trafficking, regardless of whether Rab11a(S25N) is present. In addition, whole-cell CaV2.2 currents are reduced by co-expression of Rab11a(S25N) in the presence of α2δ-1, but not α2δ-3. Taken together these data suggest that α2δ subtypes participate in distinct trafficking pathways which in turn influence the localisation and function of CaV2.2.

scholarly journals Gradients of phosphatidylserine contribute to plasma membrane charge localization and cell polarity in fission yeast

2017 ◽  
Vol 28 (1) ◽  
pp. 210-220 ◽  
Author(s):  
Armin Haupt ◽  
Nicolas Minc
Keyword(s):  
Plasma Membrane ◽  
Fission Yeast ◽  
Rho Gtpases ◽  
Cell Types ◽  
Dependent Manner ◽  
Surface Charges ◽  
Charge Localization ◽  
Membrane Charge ◽  
Altered Cell ◽  
And Function

Surface charges at the inner leaflet of the plasma membrane may contribute to regulate the surface recruitment of key signaling factors. Phosphatidylserine (PS) is an abundant charged lipid that may regulate charge distribution in different cell types. Here we characterize the subcellular distribution and function of PS in the rod-shaped, polarized fission yeast. We find that PS preferably accumulates at cell tips and defines a gradient of negative charges along the cell surface. This polarization depends on actin-mediated endocytosis and contributes to the subcellular partitioning of charged polarity-regulating Rho GTPases like Rho1 or Cdc42 in a protein charge–dependent manner. Cells depleted of PS have altered cell dimensions and fail to properly regulate growth from the second end, suggesting a role for PS and membrane charge in polarized cell growth.

scholarly journals Rab11-dependent recycling of calcium channels is mediated by auxiliary subunit α2δ-1 but not α2δ-3

2021 ◽  
Author(s):  
James O. Meyer ◽  
Annette C. Dolphin
Keyword(s):  
Plasma Membrane ◽  
Calcium Channels ◽  
Dominant Negative ◽  
Calcium Currents ◽  
Dependent Manner ◽  
Auxiliary Subunit ◽  
Endosomal Recycling ◽  
Summary Statement ◽  
Recycling Pathway ◽  
And Function

AbstractN-type voltage-gated calcium channels (CaV2.2) are predominantly expressed at presynaptic terminals, and their function is regulated by auxiliary α2δ and β subunits. All four mammalian α2δ subunits enhance calcium currents through CaV1 and CaV2 channels, and this increase is attributed, in part, to increased CaV expression at the plasma membrane. In the present study we provide evidence that α2δ-1, like α2δ-2, is recycled to the plasma membrane through a Rab11a-dependent endosomal recycling pathway. Using a dominant-negative Rab11a mutant, Rab11a(S25N), we show that α2δ-1 increases plasma membrane CaV2.2 expression by increasing the rate and extent of net forward CaV2.2 trafficking in a Rab11a-dependent manner. Dominant-negative Rab11a also reduces the ability of α2δ-1 to increase CaV2.2 expression on the cell-surface of hippocampal neurites. In contrast, α2δ-3 does not enhance rapid forward CaV2.2 trafficking, regardless of whether Rab11a(S25N) is present. In addition, whole-cell CaV2.2 currents are reduced by co-expression of Rab11a(S25N) in the presence of α2δ-1, but not α2δ-3. Taken together these data suggest that α2δ subtypes participate in distinct trafficking pathways which in turn influence the localisation and function of CaV2.2.Summary statementThe calcium channel auxiliary subunit α2δ-1 but not α2δ-3 participates in Rab11a-dependent recycling, which in turn influences the localisation and function of CaV2.2.

scholarly journals Actin-membrane interaction in fibroblasts: what proteins are involved in this association?

1984 ◽  
Vol 99 (1) ◽  
pp. 95s-103s ◽  
Author(s):  
P Mangeat ◽  
K Burridge
Keyword(s):  
Plasma Membrane ◽  
Actin Filaments ◽  
Stress Fiber ◽  
Membrane Interaction ◽  
Microfilament Bundles ◽  
The Family ◽  
Form Part ◽  
Membrane Attachment ◽  
A Chain ◽  
And Function

In this review we discuss some of the proteins for which a role in linking actin to the fibroblast plasma membrane has been suggested. We focus on the family of proteins related to erythrocyte spectrin, proteins that have generally been viewed as having an organization and a function in actin-membrane attachment similar to those of erythrocyte spectrin. Experiments in which we precipitated the nonerythrocyte spectrin within living fibroblasts have led us to question this supposed similarity of organization and function of the nonerythrocyte and erythrocyte spectrins. Intracellular precipitation of fibroblast spectrin does not affect the integrity of the major actin-containing structures, the stress fiber microfilament bundles. Unexpectedly, however, we found that the precipitation of spectrin results in a condensation and altered distribution of the vimentin class of intermediate filaments in most cells examined. Although fibroblast spectrin may have a role in the attachment of some of the cortical, submembranous actin, it is surprising how little the intracellular immunoprecipitation of the spectrin affects the cells. Several proteins have been found concentrated at the ends of stress fibers, where the actin filaments terminate at focal contacts. Two of these proteins, alpha-actinin and fimbrin, have properties that suggest that they are not involved in the attachment of the ends of the bundles to the membrane but are more probably involved in the organization and cross-linking of the filaments within the bundles. On the other hand, vinculin and talin are two proteins that interact with each other and may form part of a chain of attachments between the ends of the microfilament bundles and the focal contact membrane. Their role in this attachment, however, has not been established and further work is needed to examine their interaction with actin and to identify any other components with which they may interact, particularly in the plasma membrane.

scholarly journals Impact of Membrane Lipids on UapA and AzgA Transporter Subcellular Localization and Activity in Aspergillus nidulans

2021 ◽  
Vol 7 (7) ◽  
pp. 514
Author(s):  
Mariangela Dionysopoulou ◽  
George Diallinas
Keyword(s):  
Plasma Membrane ◽  
Subcellular Localization ◽  
Aspergillus Nidulans ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Lipid Biosynthesis ◽  
Transport Kinetics ◽  
Negative Effect ◽  
And Function

Recent biochemical and biophysical evidence have established that membrane lipids, namely phospholipids, sphingolipids and sterols, are critical for the function of eukaryotic plasma membrane transporters. Here, we study the effect of selected membrane lipid biosynthesis mutations and of the ergosterol-related antifungal itraconazole on the subcellular localization, stability and transport kinetics of two well-studied purine transporters, UapA and AzgA, in Aspergillus nidulans. We show that genetic reduction in biosynthesis of ergosterol, sphingolipids or phosphoinositides arrest A. nidulans growth after germling formation, but solely blocks in early steps of ergosterol (Erg11) or sphingolipid (BasA) synthesis have a negative effect on plasma membrane (PM) localization and stability of transporters before growth arrest. Surprisingly, the fraction of UapA or AzgA that reaches the PM in lipid biosynthesis mutants is shown to conserve normal apparent transport kinetics. We further show that turnover of UapA, which is the transporter mostly sensitive to membrane lipid content modification, occurs during its trafficking and by enhanced endocytosis, and is partly dependent on autophagy and Hect-type HulARsp5 ubiquitination. Our results point out that the role of specific membrane lipids on transporter biogenesis and function in vivo is complex, combinatorial and transporter-dependent.

scholarly journals Plasma membrane integrity in health and disease: significance and therapeutic potential

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Catarina Dias ◽  
Jesper Nylandsted
Keyword(s):  
Plasma Membrane ◽  
Therapeutic Potential ◽  
Calcium Influx ◽  
Membrane Integrity ◽  
Cell Types ◽  
Physical Parameters ◽  
Membrane Repair ◽  
Plasma Membrane Integrity ◽  
Repair Mechanisms ◽  
And Function

AbstractMaintenance of plasma membrane integrity is essential for normal cell viability and function. Thus, robust membrane repair mechanisms have evolved to counteract the eminent threat of a torn plasma membrane. Different repair mechanisms and the bio-physical parameters required for efficient repair are now emerging from different research groups. However, less is known about when these mechanisms come into play. This review focuses on the existence of membrane disruptions and repair mechanisms in both physiological and pathological conditions, and across multiple cell types, albeit to different degrees. Fundamentally, irrespective of the source of membrane disruption, aberrant calcium influx is the common stimulus that activates the membrane repair response. Inadequate repair responses can tip the balance between physiology and pathology, highlighting the significance of plasma membrane integrity. For example, an over-activated repair response can promote cancer invasion, while the inability to efficiently repair membrane can drive neurodegeneration and muscular dystrophies. The interdisciplinary view explored here emphasises the widespread potential of targeting plasma membrane repair mechanisms for therapeutic purposes.

scholarly journals Vacuolar-type H+-ATPase regulates cytoplasmic pH in Toxoplasma gondii tachyzoites

1998 ◽  
Vol 330 (2) ◽  
pp. 853-860 ◽  
Author(s):  
N. J. Silvia MORENO ◽  
Li ZHONG ◽  
Hong-Gang LU ◽  
Wanderley DE SOUZA ◽  
Marlene BENCHIMOL
Keyword(s):  
Plasma Membrane ◽  
Toxoplasma Gondii ◽  
Laser Scanning ◽  
Membrane Surface ◽  
Surface Proteins ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Dependent Manner ◽  
Cytoplasmic Ph ◽  
Bafilomycin A1

Cytoplasmic pH (pHi) regulation was studied in Toxoplasma gondii tachyzoites by using the fluorescent dye 2ʹ,7ʹ-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein. Their mean baseline pHi (7.07±0.06; n = 5) was not significantly affected in the absence of extracellular Na+, K+ or HCO3- but was significantly decreased in a dose-dependent manner by low concentrations of N,Nʹ-dicyclohexylcarbodi-imide (DCCD), N-ethylmaleimide (NEM) or bafilomycin A1. Bafilomycin A1 also inhibited the recovery of tachyzoite pHi after an acid load with sodium propionate. Similar concentrations of DCCD, NEM and bafilomycin A1 produced depolarization of the plasma membrane potential as measured with bis-(1,3-diethylthiobarbituric)trimethineoxonol (bisoxonol), and DCCD prevented the hyperpolarization that accompanies acid extrusion after the addition of propionate, in agreement with the electrogenic nature of this pump. Confocal laser scanning microscopy indicated that, in addition to being located in cytoplasmic vacuoles, the vacuolar (V)-H+-ATPase of T. gondii tachyzoites is also located in the plasma membrane. Surface localization of the V-H+-ATPase was confirmed by experiments using biotinylation of cell surface proteins and immunoprecipitation with antibodies against V-H+-ATPases. Taken together, the results are consistent with the presence of a functional V-H+-ATPase in the plasma membrane of these intracellular parasites and with an important role of this enzyme in the regulation of pHi homoeostasis in these cells.

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