scholarly journals Kv2 channels create endoplasmic reticulum / plasma membrane junctions: a brief history of Kv2 channel subcellular localization

Channels ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 88-101 ◽  
Author(s):  
Ben Johnson ◽  
Ashley N. Leek ◽  
Michael M. Tamkun
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Subcellular Localization ◽  
History Of

scholarly journals ER-Localized PIN Carriers: Regulators of Intracellular Auxin Homeostasis

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1527
Author(s):  
Nayyer Abdollahi Sisi ◽  
Kamil Růžička
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Subcellular Localization ◽  
Plant Development ◽  
Current Knowledge ◽  
Structural Features ◽  
Structure Evolution ◽  
Auxin Homeostasis ◽  
Auxin Efflux Carriers ◽  
Hydrophilic Loop

The proper distribution of the hormone auxin is essential for plant development. It is channeled by auxin efflux carriers of the PIN family, typically asymmetrically located on the plasma membrane (PM). Several studies demonstrated that some PIN transporters are also located at the endoplasmic reticulum (ER). From the PM-PINs, they differ in a shorter internal hydrophilic loop, which carries the most important structural features required for their subcellular localization, but their biological role is otherwise relatively poorly known. We discuss how ER-PINs take part in maintaining intracellular auxin homeostasis, possibly by modulating the internal levels of IAA; it seems that the exact identity of the metabolites downstream of ER-PINs is not entirely clear as well. We further review the current knowledge about their predicted structure, evolution and localization. Finally, we also summarize their role in plant development.

scholarly journals Subcellular localization of the enzyme that forms mannosyl retinyl phosphate from guanosine diphosphate [14C]mannose and retinyl phosphate

1979 ◽  
Vol 180 (3) ◽  
pp. 449-453 ◽  
Author(s):  
M J Smith ◽  
J B Schreiber ◽  
G Wolf
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Subcellular Localization ◽  
Rat Liver ◽  
Rough Endoplasmic Reticulum ◽  
Subcellular Distribution ◽  
Smooth Endoplasmic Reticulum ◽  
Marker Enzymes ◽  
Guanosine Diphosphate

The subcellular distribution of the enzyme catalysing the conversion of retinyl phosphate and GDP-[14C]mannose into [14C]mannosyl retinyl phosphate was determined by using subcellular fractions of rat liver. Purity of fractions, as determined by marker enzymes, was 80% or better. The amount of mannosyl retinyl phosphate formed (pmol/min per mg of protein) for each fraction was: rough endoplasmic reticulum 0.48 +/- 0.09 (mean +/- S.D.); smooth membranes (consisting of 60% smooth endoplasmic reticulum and 40% Golgi apparatus), 0.18 +/- 0.03; Golgi apparatus, 0.13 +/- 0.03; and plasma membrane 0.02.

The subcellular localization of testicular sulfogalactoglycerolipid

1980 ◽  
Vol 58 (3) ◽  
pp. 225-229 ◽  
Author(s):  
Abbey Klugerman ◽  
Mary Judith Kornblatt
Keyword(s):  
Alkaline Phosphatase ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Subcellular Localization ◽  
Density Distribution ◽  
Equilibrium Density ◽  
Enzyme Markers ◽  
Germinal Cells

The subcellular localization of sulfogalactoglycerolipid in rat testicular germinal cells was determined. The sulfolipid of young rats was labelled in vivo with Na235SO4. Rat testis cell suspensions were prepared, homogenized, and centrifuged on linear, continuous, sucrose gradients. The labelled lipid had the identical equilibrium density distribution pattern as alkaline phosphatase, an enzyme of the plasma membrane. The pattern of the sulfolipid was different from the patterns of enzyme markers for the Golgi apparatus, lysosomes, mitochondria, and endoplasmic reticulum. From these results, we conclude that sulfogalactoglycerolipid is located on the plasma membrane of rat testicular germinal cells.

Triple Fixation For Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 90-91 ◽  
Author(s):  
M. A. Hayat
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Beam ◽  
Plasma Membrane ◽  
Myelin Sheath ◽  
Good Deal ◽  
Granular Structure ◽  
Oxidizing Agent ◽  
Fixation Technique ◽  
Large Clusters

Potassium permanganate has been successfully employed to study membranous structures such as endoplasmic reticulum, Golgi, plastids, plasma membrane and myelin sheath. Since KMnO4 is a strong oxidizing agent, deposition of manganese or its oxides account for some of the observed contrast in the lipoprotein membranes, but a good deal of it is due to the removal of background proteins either by dehydration agents or by volatalization under the electron beam. Tissues fixed with KMnO4 exhibit somewhat granular structure because of the deposition of large clusters of stain molecules. The gross arrangement of membranes can also be modified. Since the aim of a good fixation technique is to preserve satisfactorily the cell as a whole and not the best preservation of only a small part of it, a combination of a mixture of glutaraldehyde and acrolein to obtain general preservation and KMnO4 to enhance contrast was employed to fix plant embryos, green algae and fungi.

scholarly journals Synaptotagmins at the endoplasmic reticulum–plasma membrane contact sites maintain diacylglycerol homeostasis during abiotic stress

2021 ◽  
Author(s):  
Noemi Ruiz-Lopez ◽  
Jessica Pérez-Sancho ◽  
Alicia Esteban del Valle ◽  
Richard P Haslam ◽  
Steffen Vanneste ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Abiotic Stress ◽  
Fluorescent Protein ◽  
Mechanical Damage ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact ◽  
Green Fluorescent

Abstract Endoplasmic reticulum-plasma membrane contact sites (ER-PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis thaliana mutants lacking the ER-PM protein tether synaptotagmin1 (SYT1) exhibit decreased plasma membrane (PM) integrity under multiple abiotic stresses such as freezing, high salt, osmotic stress and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER-PM tether that also functions in maintaining PM integrity. The ER-PM CS localization of SYT1 and SYT3 is dependent on PM phosphatidylinositol-4-phosphate and is regulated by abiotic stress. Lipidomic analysis revealed that cold stress increased the accumulation of diacylglycerol at the PM in a syt1/3 double mutant relative to wild type while the levels of most glycerolipid species remain unchanged. Additionally, the SYT1-green fluorescent protein (GFP) fusion preferentially binds diacylglycerol in vivo with little affinity for polar glycerolipids. Our work uncovers a SYT-dependent mechanism of stress adaptation counteracting the detrimental accumulation of diacylglycerol at the PM produced during episodes of abiotic stress.

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 Septin-dependent compartmentalization of the endoplasmic reticulum during yeast polarized growth

2005 ◽  
Vol 169 (6) ◽  
pp. 897-908 ◽  
Author(s):  
Cosima Luedeke ◽  
Stéphanie Buvelot Frei ◽  
Ivo Sbalzarini ◽  
Heinz Schwarz ◽  
Anne Spang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Diffusion Barriers ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Protein Diffusion ◽  
Ultrastructural Studies ◽  
Bud Neck ◽  
Er Membrane

Polarized cells frequently use diffusion barriers to separate plasma membrane domains. It is unknown whether diffusion barriers also compartmentalize intracellular organelles. We used photobleaching techniques to characterize protein diffusion in the yeast endoplasmic reticulum (ER). Although a soluble protein diffused rapidly throughout the ER lumen, diffusion of ER membrane proteins was restricted at the bud neck. Ultrastructural studies and fluorescence microscopy revealed the presence of a ring of smooth ER at the bud neck. This ER domain and the restriction of diffusion for ER membrane proteins through the bud neck depended on septin function. The membrane-associated protein Bud6 localized to the bud neck in a septin-dependent manner and was required to restrict the diffusion of ER membrane proteins. Our results indicate that Bud6 acts downstream of septins to assemble a fence in the ER membrane at the bud neck. Thus, in polarized yeast cells, diffusion barriers compartmentalize the ER and the plasma membrane along parallel lines.

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