scholarly journals The phospholipase complex PAFAH Ib regulates the functional organization of the Golgi complex

2010 ◽  
Vol 190 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Marie E. Bechler ◽  
Anne M. Doody ◽  
Esther Racoosin ◽  
Lin Lin ◽  
Kelvin H. Lee ◽  
...  
Keyword(s):  
Golgi Complex ◽  
Functional Organization ◽  
Platelet Activating Factor ◽  
Pla2 Activity ◽  
Tubule Formation ◽  
Platelet Activating Factor Acetylhydrolase ◽  
Catalytically Active ◽  
Membrane Tubulation ◽  
Dependent Transport ◽  
And Function

We report that platelet-activating factor acetylhydrolase (PAFAH) Ib, comprised of two phospholipase A2 (PLA2) subunits, α1 and α2, and a third subunit, the dynein regulator lissencephaly 1 (LIS1), mediates the structure and function of the Golgi complex. Both α1 and α2 partially localize on Golgi membranes, and purified catalytically active, but not inactive α1 and α2 induce Golgi membrane tubule formation in a reconstitution system. Overexpression of wild-type or mutant α1 or α2 revealed that both PLA2 activity and LIS1 are important for maintaining Golgi structure. Knockdown of PAFAH Ib subunits fragments the Golgi complex, inhibits tubule-mediated reassembly of intact Golgi ribbons, and slows secretion of cargo. Our results demonstrate a cooperative interplay between the PLA2 activity of α1 and α2 with LIS1 to facilitate the functional organization of the Golgi complex, thereby suggesting a model that links phospholipid remodeling and membrane tubulation to dynein-dependent transport.

scholarly journals The phospholipase A2 enzyme complex PAFAH Ib mediates endosomal membrane tubule formation and trafficking

2011 ◽  
Vol 22 (13) ◽  
pp. 2348-2359 ◽  
Author(s):  
Marie E. Bechler ◽  
Anne M. Doody ◽  
Kevin D. Ha ◽  
Bret L. Judson ◽  
Ina Chen ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Platelet Activating Factor ◽  
Enzyme Complex ◽  
Tubule Formation ◽  
Catalytic Subunits ◽  
Endosomal Membrane ◽  
Platelet Activating Factor Acetylhydrolase ◽  
Membrane Tubules ◽  
And Function ◽  
Interfering Rna

Previous studies have shown that membrane tubule–mediated export from endosomal compartments requires a cytoplasmic phospholipase A2 (PLA2) activity. Here we report that the cytoplasmic PLA2 enzyme complex platelet-activating factor acetylhydrolase (PAFAH) Ib, which consists of α1, α2, and LIS1 subunits, regulates the distribution and function of endosomes. The catalytic subunits α1 and α2 are located on early-sorting endosomes and the central endocytic recycling compartment (ERC) and their overexpression, but not overexpression of their catalytically inactive counterparts, induced endosome membrane tubules. In addition, overexpression α1 and α2 altered normal endocytic trafficking; transferrin was recycled back to the plasma membrane directly from peripheral early-sorting endosomes instead of making an intermediate stop in the ERC. Consistent with these results, small interfering RNA–mediated knockdown of α1 and α2 significantly inhibited the formation of endosome membrane tubules and delayed the recycling of transferrin. In addition, the results agree with previous reports that PAFAH Ib α1 and α2 expression levels affect the distribution of endosomes within the cell through interactions with the dynein regulator LIS1. These studies show that PAFAH Ib regulates endocytic membrane trafficking through novel mechanisms involving both PLA2 activity and LIS1-dependent dynein function.

scholarly journals Golgi spectrin: identification of an erythroid beta-spectrin homolog associated with the Golgi complex.

1994 ◽  
Vol 127 (3) ◽  
pp. 707-723 ◽  
Author(s):  
K A Beck ◽  
J A Buchanan ◽  
V Malhotra ◽  
W J Nelson
Keyword(s):  
Golgi Complex ◽  
Structural Integrity ◽  
Functional Organization ◽  
Brefeldin A ◽  
Cell Types ◽  
Loss Of Function ◽  
Dynamic Relationship ◽  
Golgi Membranes ◽  
Golgi Structure ◽  
And Function

Spectrin is a major component of a membrane-associated cytoskeleton involved in the maintenance of membrane structural integrity and the generation of functionally distinct membrane protein domains. Here, we show that a homolog of erythrocyte beta-spectrin (beta I sigma*) co-localizes with markers of the Golgi complex in a variety of cell types, and that microinjected beta-spectrin codistributes with elements of the Golgi complex. Significantly, we show a dynamic relationship between beta-spectrin and the structural and functional organization of the Golgi complex. Disruption of both Golgi structure and function, either in mitotic cells or following addition of brefeldin A, is accompanied by loss of beta-spectrin from Golgi membranes and dispersal in the cytoplasm. In contrast, perturbation of Golgi structure without a loss of function, by the addition of nocodazole, results in retention of beta-spectrin with the dispersed Golgi elements. These results indicate that the association of beta-spectrin with Golgi membranes is coupled to Golgi organization and function.

scholarly journals Lysophosphatidic acid acyltransferase 3 regulates Golgi complex structure and function

2009 ◽  
Vol 186 (2) ◽  
pp. 211-218 ◽  
Author(s):  
John A. Schmidt ◽  
William J. Brown
Keyword(s):  
Lysophosphatidic Acid ◽  
Golgi Complex ◽  
Membrane Trafficking ◽  
Functional Organization ◽  
Complex Structure ◽  
Golgi Membrane ◽  
Direct Role ◽  
Tubule Formation ◽  
In Cells

Recent studies have suggested that the functional organization of the Golgi complex is dependent on phospholipid remodeling enzymes. Here, we report the identification of an integral membrane lysophosphatidic acid–specific acyltransferase, LPAAT3, which regulates Golgi membrane tubule formation, trafficking, and structure by altering phospholipids and lysophospholipids. Overexpression of LPAAT3 significantly inhibited the formation of Golgi membrane tubules in vivo and in vitro. Anterograde and retrograde protein trafficking was slower in cells overexpressing LPAAT3 and accelerated in cells with reduced expression (by siRNA). Golgi morphology was also dependent on LPAAT3 because its knockdown caused the Golgi to become fragmented. These data are the first to show a direct role for a specific phospholipid acyltransferase in regulating membrane trafficking and organelle structure.

scholarly journals Lipoprotein-associated phospholipase A2 (Lp-PLA2) activity, platelet-activating factor acetylhydrolase (PAF-AH) in leukocytes and body composition in healthy adults

2009 ◽  
Vol 8 (1) ◽  
pp. 19 ◽  
Author(s):  
Paraskevi Detopoulou ◽  
Tzortzis Nomikos ◽  
Elizabeth Fragopoulou ◽  
Demosthenis B Panagiotakos ◽  
Christos Pitsavos ◽  
...  
Keyword(s):  
Body Composition ◽  
Phospholipase A2 ◽  
Platelet Activating Factor ◽  
Healthy Adults ◽  
Pla2 Activity ◽  
Platelet Activating Factor Acetylhydrolase

A Mutation in Plasma Platelet-activating Factor Acetylhydrolase (Val279Phe) Is a Genetic Risk Factor for Cerebral Hemorrhage but not for Hypertension

1998 ◽  
Vol 80 (09) ◽  
pp. 372-375 ◽  
Author(s):  
Hidemi Yoshida ◽  
Tadaatsu Imaizumi ◽  
Koji Fujimoto ◽  
Hiroyuki Itaya ◽  
Makoto Hiramoto ◽  
...  
Keyword(s):  
Risk Factor ◽  
Genetic Risk ◽  
Platelet Activating Factor ◽  
Vascular Diseases ◽  
Genetic Risk Factor ◽  
Brain Hemorrhage ◽  
Platelet Activating Factor Acetylhydrolase ◽  
Paf Acetylhydrolase ◽  
Polymerase Chain ◽  
The Difference

SummaryPlatelet-activating factor (PAF) acetylhydrolase is an enzyme that inactivates PAF. Deficiency of this enzyme is caused by a missense mutation in the gene. We previously found a higher prevalence of this mutation in patients with ischemic stroke. This fact suggests that the mutation might enhance the risk for stroke through its association with hypertension. We have addressed this hypothesis by analyzing the prevalence of the mutation in hypertension. We studied 138 patients with essential hypertension, 99 patients with brain hemorrhage, and 270 healthy controls. Genomic DNA was analyzed for the mutant allele by the polymerase-chain reaction. The prevalence of the mutation was 29.3% (27.4% heterozygotes and 1.9% homozygotes) in controls and 36.2% in hypertensives and the difference was not significant. The prevalence in patients with brain hemorrhage was significantly higher than the control: 32.6% heterozygotes and 6.1% homozygotes (p <0.05). PAF acetylhydrolase deficiency may be a genetic risk factor for vascular diseases.

scholarly journals Consumption of Enriched Yogurt with PAF Inhibitors from Olive Pomace Affects the Major Enzymes of PAF Metabolism: A Randomized, Double Blind, Three Arm Trial

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 801
Author(s):  
Maria Detopoulou ◽  
Agathi Ntzouvani ◽  
Filio Petsini ◽  
Labrini Gavriil ◽  
Εlizabeth Fragopoulou ◽  
...  
Keyword(s):  
Platelet Activating Factor ◽  
Lipid Mediator ◽  
Olive Pomace ◽  
Double Blind ◽  
Promising Alternative ◽  
Catabolic Enzymes ◽  
Platelet Activating Factor Acetylhydrolase ◽  
The Impact ◽  
By Products ◽  
Apparently Healthy

Platelet-activating factor (PAF), a proinflammatory lipid mediator, plays a crucial role in the formation of the atherosclerotic plaque. Therefore, the inhibition of endothelium inflammation by nutraceuticals, such as PAF inhibitors, is a promising alternative for preventing cardiovascular diseases. The aim of the present study was to evaluate the impact of a new functional yogurt enriched with PAF inhibitors of natural origin from olive oil by-products on PAF metabolism. Ninety-two apparently healthy, but mainly overweight volunteers (35–65 years) were randomly allocated into three groups by block-randomization. The activities of PAF’s biosynthetic and catabolic enzymes were measured, specifically two isoforms of acetyl-CoA:lyso-PAF acetyltransferase (LPCATs), cytidine 5′-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT) and two isoforms of platelet activating factor acetylhydrolase in leucocytes (PAF-AH) and plasma (lipoprotein associated phospholipase-A2, LpPLA2). The intake of the enriched yogurt resulted in reduced PAF-CPT and LpPLA2 activities. No difference was observed in the activities of the two isoforms of lyso PAF-AT. In conclusion, intake of yogurt enriched in PAF inhibitors could favorably modulate PAF biosynthetic and catabolic pathways.

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