Lipid homoeostasis and Golgi secretory function

2006 ◽  
Vol 34 (3) ◽  
pp. 363-366 ◽  
Author(s):  
S. Lev
Keyword(s):  
Lipid Binding ◽  
Membrane Domains ◽  
Functional Identity ◽  
Secretory Function ◽  
Critical Levels ◽  
Exact Role ◽  
Golgi Membranes ◽  
Golgi Secretory Function ◽  
Underlying Mechanisms ◽  
Specific Membrane

The unique lipid composition of the Golgi membranes is critical for maintaining their structural and functional identity, and is regulated by local lipid metabolism, a variety of lipid-binding, -modifying, -sensing and -transfer proteins, and by selective lipid sorting mechanisms. A growing body of evidence suggests that certain lipids, such as phosphoinositides and diacylglycerol, regulate Golgi-mediated transport events. However, their exact role in this process, and the underlying mechanisms that maintain their critical levels in specific membrane domains of the Golgi apparatus, remain poorly understood. Nevertheless, recent advances have revealed key regulators of lipid homoeostasis in the Golgi complex and have demonstrated their role in Golgi secretory function.

scholarly journals A phosphatidylinositol transfer protein controls the phosphatidylcholine content of yeast Golgi membranes

1994 ◽  
Vol 124 (3) ◽  
pp. 273-287 ◽  
Author(s):  
TP McGee ◽  
HB Skinner ◽  
EA Whitters ◽  
SA Henry ◽  
VA Bankaitis
Keyword(s):  
Protein Transport ◽  
Phospholipid Composition ◽  
Membrane Phospholipid ◽  
Secretory Function ◽  
Golgi Membrane ◽  
Transfer Protein ◽  
Golgi Membranes ◽  
Phosphatidylcholine Biosynthesis ◽  
Phosphatidylinositol Transfer

SEC14p is required for protein transport from the yeast Golgi complex. We describe a quantitative analysis of yeast bulk membrane and Golgi membrane phospholipid composition under conditions where Golgi secretory function has been uncoupled from its usual SEC14p requirement. The data demonstrate that SEC14p specifically functions to maintain a reduced phosphatidylcholine content in Golgi membranes and indicate that overproduction of SEC14p markedly reduces the apparent rate of phosphatidylcholine biosynthesis via the CDP-choline pathway in vivo. We suggest that SEC14p serves as a sensor of Golgi membrane phospholipid composition through which the activity of the CDP-choline pathway in Golgi membranes is regulated such that a phosphatidylcholine content that is compatible with the essential secretory function of these membranes is maintained.

scholarly journals Expression of Sugar Transporters by In Vivo Electroporation and Particle Gun Methods in the Rat Liver: Localization to Specific Membrane Domains.

2001 ◽  
Vol 34 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Yasuo Shinoda ◽  
Takeshi Suzuki ◽  
Minako Sugawara-Yokoo ◽  
Shinya Nagamatsu ◽  
Hiroyuki Kuwano ◽  
...  
Keyword(s):  
Rat Liver ◽  
Membrane Domains ◽  
Particle Gun ◽  
In Vivo Electroporation ◽  
Sugar Transporters ◽  
Specific Membrane

scholarly journals Evidence for an Intrinsic Toxicity of Phosphatidylcholine to Sec14p-dependent Protein Transport from the Yeast Golgi Complex

2001 ◽  
Vol 12 (4) ◽  
pp. 1117-1129 ◽  
Author(s):  
Zhigang Xie ◽  
Min Fang ◽  
Vytas A. Bankaitis
Keyword(s):  
Phospholipase D ◽  
Protein Transport ◽  
Choline Uptake ◽  
Secretory Function ◽  
Direct Production ◽  
Methylation Pathway ◽  
The Media ◽  
Golgi Secretory Function ◽  
Phosphatidylinositol Transfer ◽  
Cytidine Diphosphate

Yeast phosphatidylinositol-transfer protein (Sec14p) is essential for Golgi secretory function and cell viability. This requirement of Sec14p is relieved by genetic inactivation of the cytidine diphosphate-choline pathway for phosphatidycholine (PtdCho) biosynthesis. Standard phenotypic analyses indicate that inactivation of the phosphatidylethanolamine (PtdEtn) pathway for PtdCho biosynthesis, however, does not rescue the growth and secretory defects associated with Sec14p deficiency. We now report inhibition of choline uptake from the media reveals an efficient “bypass Sec14p” phenotype associated with PtdEtn-methylation pathway defects. We further show that the bypass Sec14p phenotype associated with PtdEtn-methylation pathway defects resembles other bypass Sec14p mutations in its dependence on phospholipase D activity. Finally, we find that increased dosage of enzymes that catalyze phospholipase D-independent turnover of PtdCho, via mechanisms that do not result in a direct production of phosphatidic acid or diacylglycerol, effect a partial rescue of sec14-1ts-associated growth defects. Taken together, these data support the idea that PtdCho is intrinsically toxic to yeast Golgi secretory function.

scholarly journals Sphingomyelin homeostasis is required to form functional enzymatic domains at the trans-Golgi network

2014 ◽  
Vol 206 (5) ◽  
pp. 609-618 ◽  
Author(s):  
Josse van Galen ◽  
Felix Campelo ◽  
Emma Martínez-Alonso ◽  
Margherita Scarpa ◽  
José Ángel Martínez-Menárguez ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Hela Cells ◽  
Transmembrane Proteins ◽  
Short Chain ◽  
Membrane Domains ◽  
Trans Golgi Network ◽  
And Function ◽  
Golgi Network ◽  
Specific Membrane

Do lipids such as sphingomyelin (SM) that are known to assemble into specific membrane domains play a role in the organization and function of transmembrane proteins? In this paper, we show that disruption of SM homeostasis at the trans-Golgi network (TGN) by treatment of HeLa cells with d-ceramide-C6, which was converted together with phosphatidylcholine to short-chain SM and diacylglycerol by SM synthase, led to the segregation of Golgi-resident proteins from each other. We found that TGN46, which cycles between the TGN and the plasma membrane, was not sialylated by a sialyltransferase at the TGN and that this enzyme and its substrate TGN46 could not physically interact with each other. Our results suggest that SM organizes transmembrane proteins into functional enzymatic domains at the TGN.

scholarly journals Control of lipid domain organization by a biomimetic contractile actomyosin cortex

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Sven Kenjiro Vogel ◽  
Ferdinand Greiss ◽  
Alena Khmelinskaia ◽  
Petra Schwille
Keyword(s):  
Cell Membrane ◽  
Actin Filaments ◽  
Shape Change ◽  
Line Tension ◽  
Membrane Domains ◽  
Lipid Domain ◽  
Actin Cortex ◽  
Control Dynamic ◽  
Underlying Mechanisms ◽  
Lateral Organization

The cell membrane is a heterogeneously organized composite with lipid-protein micro-domains. The contractile actin cortex may govern the lateral organization of these domains in the cell membrane, yet the underlying mechanisms are not known. We recently reconstituted minimal actin cortices (MACs) (Vogel et al., 2013b) and here advanced our assay to investigate effects of rearranging actin filaments on the lateral membrane organization by introducing various phase-separated lipid mono- and bilayers to the MACs. The addition of actin filaments reorganized membrane domains. We found that the process reached a steady state where line tension and lateral crowding balanced. Moreover, the phase boundary allowed myosin driven actin filament rearrangements to actively move individual lipid domains, often accompanied by their shape change, fusion or splitting. Our findings illustrate how actin cortex remodeling in cells may control dynamic rearrangements of lipids and other molecules inside domains without directly binding to actin filaments.

scholarly journals Focal cholesterol depletion during Fcγ receptor-mediated phagocytosis contributes to Lyn kinase regulation

2018 ◽  
Author(s):  
Stella M. Lu ◽  
Allen Volchuk ◽  
Gregory D. Fairn
Keyword(s):  
Cholesterol Depletion ◽  
Membrane Domains ◽  
Kinase Signaling ◽  
Protein Markers ◽  
Fcγ Receptor ◽  
Lyn Kinase ◽  
Selective Depletion ◽  
Summary Statement ◽  
Specific Membrane ◽  
Genetically Encoded Biosensor

AbstractCholesterol-rich nanodomains, historically referred to as lipid rafts, have previously been reported to be critical for proper Fcγ Receptor and Lyn kinase signaling during phagocytosis. Throughout the initial stages of phagocytosis, the nascent phagosome is actively remodeled by localized lipid metabolism and exocytosis. However, to date, little is known about the dynamics of cholesterol during this stage of particle engulfment. Using a genetically-encoded biosensor for cholesterol, we find that cholesterol is depleted from the nascent phagosome prior to sealing. Additionally, protein markers of both cholesterol-rich and cholesterol-poor nanodomains also clear from the site of phagocytosis arguing against the selective depletion of specific membrane domains. Consistent with previous studies we find that exocytosis contributes to the remodeling of the nascent phagosome. The displacement of cholesterol from the forming phagosome was paralleled by Lyn kinase helping to explain the reduction of phosphotyrosine signal in the nascent phagosome. This diminution of cholesterol and Lyn from the base of the cup may aid in the processivity of the phagocytic signal during pseudopod extension, and provide an unappreciated mechanism by which Lyn kinase signaling is regulated during phagocytosis.Summary Statement: Localized exocytosis dilutes cholesterol from the phagocytic cup leading to the displacement of Lyn kinase and an attenuation of signaling.

scholarly journals Tissue factor in microvesicles shed from U87MG human glioblastoma cells induces coagulation, platelet aggregation, and thrombogenesis

Blood ◽  
1984 ◽  
Vol 64 (1) ◽  
pp. 177-184 ◽  
Author(s):  
E Bastida ◽  
A Ordinas ◽  
G Escolar ◽  
GA Jamieson
Keyword(s):  
Platelet Aggregation ◽  
Tissue Factor ◽  
Bovine Brain ◽  
Membrane Domains ◽  
Extrinsic Pathway ◽  
Intact Cells ◽  
Human Glioblastoma ◽  
Single Protein ◽  
Specific Membrane

Abstract Microvesicles (diameter ca 200 nm) from the cell-free supernatant of U87MG human glioblastoma cell caused platelet aggregation and coagulation in a manner identical with that previously shown for the intact cells. Both activities were inhibited by dansylarginine -N-(3- ethyl-1,5-pentanediyl) amide (DAPA), confirming the thrombin-dependent nature of both activities. The specific activities per microgram of protein were 2–10 times greater in the microvesicles than in the plasma membrane fraction, suggesting localization in specific membrane domains. Sucrose density centrifugation gave a single protein peak (density 1.14) with congruent procoagulant and platelet aggregating activities. Both activities required the extrinsic pathway, as shown by studies with factor-deficient plasmas, and both were inhibited by heating (60 min/100 degrees C), by reduction and alkylation, and by incubation of the microvesicles with rabbit anti-bovine brain tissue factor antibody. These observations were confirmed using microvesicles from the HL-60 human promyelocytic leukemia cells, which are known to contain tissue factor activity. The results suggest that both procoagulant and proaggregating activities are causally related through the presence of tissue factor in the microvesicles. Studies with the Baumgartner perfusion apparatus showed that U87MG microvesicles increased the size of adherent thrombi nearly tenfold and that these thrombi were associated with nucleated cells from the blood. The increase in adherent thrombi did not occur if perfusion was carried out in the presence of DAPA, confirming the role of thrombin in their formation.

scholarly journals Pollen Aperture Factor INP1 Acts Late in Aperture Formation by Excluding Specific Membrane Domains from Exine Deposition

2017 ◽  
Vol 176 (1) ◽  
pp. 326-339 ◽  
Author(s):  
Anna A. Dobritsa ◽  
Andrew B. Kirkpatrick ◽  
Sarah H. Reeder ◽  
Peng Li ◽  
Heather A. Owen
Keyword(s):  
Membrane Domains ◽  
Specific Membrane
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