scholarly journals Reversible translocation of cytidylyltransferase between cytosol and endoplasmic reticulum occurs within minutes in whole cells

1992 ◽  
Vol 282 (2) ◽  
pp. 333-338 ◽  
Author(s):  
F Tercé ◽  
M Record ◽  
H Tronchère ◽  
G Ribbes ◽  
H Chap

Addition of oleic acid to Krebs II cells induced a rapid incorporation of [3H]choline into phosphatidylcholine, since 500 microM of the fatty acid stimulated choline incorporation by 5-fold over the control after 5 min of incubation. In fact, a noticeable increase in phosphatidylcholine labelling could be monitored immediately after 1 min of cell incubation with [3H]choline, at which time 50% of cytosolic cytidylyltransferase activity (EC 2.7.7.15), the regulatory enzyme of phosphatidylcholine synthesis, was translocated on to membranes. Non-esterified [3H]oleic acid content was also increased in the same range of time in the particulate fraction. Subcellular fractionation indicated that endoplasmic reticulum was the unique binding site for cytidylyltransferase even after 1 min of incubation. Also, [3H]oleic acid accumulated mainly in the same internal membrane. Addition of exogenous albumin to cells prelabelled with [3H]oleic acid induced the release of 50% of membrane-bound cytidylyltransferase activity within 1 min, together with a decrease in unesterified oleic acid in the same membrane. Although total depletion of oleic acid was obtained, total release of membrane-bound cytidylyltransferase was not. The remaining minor pool of membrane-bound cytidylyltransferase was not affected by cell incubation with dibutyryl cyclic AMP, suggesting that this pool was neither regulated by fatty acid nor modulated by cyclic-AMP-dependent protein phosphorylation. Addition of [3H]oleic acid directly to an homogenate led to a less specific accumulation of the fatty acid in the endoplasmic reticulum, but cytidylyltransferase remained exclusively associated with this membrane. We concluded that in vivo translocation of cytidylyltransferase provoked by oleic acid concerns one specific pool of the enzyme distinct from the enzyme firmly bound to endoplasmic reticulum, but other factor(s) than fatty acid seem to be required to explain the specificity of endoplasmic reticulum for cytidylyltransferase binding.

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1245
Author(s):  
Naoufal Lakhssassi ◽  
Valéria Stefania Lopes-Caitar ◽  
Dounya Knizia ◽  
Mallory A. Cullen ◽  
Oussama Badad ◽  
...  

Soybean is the second largest source of oil worldwide. Developing soybean varieties with high levels of oleic acid is a primary goal of the soybean breeders and industry. Edible oils containing high level of oleic acid and low level of linoleic acid are considered with higher oxidative stability and can be used as a natural antioxidant in food stability. All developed high oleic acid soybeans carry two alleles; GmFAD2-1A and GmFAD2-1B. However, when planted in cold soil, a possible reduction in seed germination was reported when high seed oleic acid derived from GmFAD2-1 alleles were used. Besides the soybean fatty acid desaturase (GmFAD2-1) subfamily, the GmFAD2-2 subfamily is composed of five members, including GmFAD2-2A, GmFAD2-2B, GmFAD2-2C, GmFAD2-2D, and GmFAD2-2E. Segmental duplication of GmFAD2-1A/GmFAD2-1B, GmFAD2-2A/GmFAD2-2C, GmFAD2-2A/GmFAD2-2D, and GmFAD2-2D/GmFAD2-2C have occurred about 10.65, 27.04, 100.81, and 106.55 Mya, respectively. Using TILLING-by-Sequencing+ technology, we successfully identified 12, 8, 10, 9, and 19 EMS mutants at the GmFAD2-2A, GmFAD2-2B, GmFAD2-2C, GmFAD2-2D, and GmFAD2-2E genes, respectively. Functional analyses of newly identified mutants revealed unprecedented role of the five GmFAD2-2A, GmFAD2-2B, GmFAD2-2C, GmFAD2-2D, and GmFAD2-2E members in controlling the seed oleic acid content. Most importantly, unlike GmFAD2-1 members, subcellular localization revealed that members of the GmFAD2-2 subfamily showed a cytoplasmic localization, which may suggest the presence of an alternative fatty acid desaturase pathway in soybean for converting oleic acid content without substantially altering the traditional plastidial/ER fatty acid production.


2017 ◽  
Vol 242 (18) ◽  
pp. 1765-1771 ◽  
Author(s):  
Guinea BC Cardoso ◽  
Erivelto Chacon ◽  
Priscila GL Chacon ◽  
Pedro Bordeaux-Rego ◽  
Adriana SS Duarte ◽  
...  

Our hypothesis was to investigate the fatty acid potential as a bone induction factor. In vitro and in vivo studies were performed to evaluate this approach. Oleic acid was used in a 0.5 wt.% concentration. Polycaprolactone was used as the polymeric matrix by combining solvent-casting and particulate-leaching techniques, with a final porosity of 70 wt.%, investigated by SEM images. Contact angle measurements were produced to investigate the influence of oleic acid on polycaprolactone chains. Cell culture was performed using adipocyte-derived stem cells to evaluate biocompatibility and bioactivity properties. In addition, in vivo studies were performed to evaluate the induction potential of oleic acid addition. Adipocyte-derived stem cells were used to provide differentiation after 21 days of culture. Likewise, information were obtained with in vivo data and cellular invagination was observed on both scaffolds (polycaprolactone and polycaprolactone /oleic acid); interestingly, the scaffold with oleic acid addition demonstrated that cellular migrations are not related to the surrounding tissue, indicating bioactive potential. Our hypothesis is that fatty acid may be used as a potential induction factor for bone tissue engineering. The study’s findings indicate oleic acid as a possible agent for bone induction, according to data on cell differentiation, proliferation, and migration. Impact statement The biomaterial combined in this study on bone regeneration is innovative and shows promising results in the treatment of bone lesions. Polycaprolactone (PCL) and oleic acid have been studied separately. In this research, we combined biomaterials to assess the stimulus and the speed of bone healing.


Helia ◽  
2015 ◽  
Vol 38 (62) ◽  
Author(s):  
Claudio Ferfuia ◽  
Maurizio Turi ◽  
Gian Paolo Vannozzi

AbstractHigh temperature enhances the oleic acid content in the oil of normal cultivars but conflicting results are reported on temperature effects on oleic acid content in HO cultivars: either no effect or an increase in oleic acid content with temperature. To investigate the effects of temperature on HO genotypes under natural field conditions, a three-year field trial was conducted using two sowing dates and three HO genotypes (two inbred lines and one hybrid). To compare our results with previous works, growing degree-days (GDD) were computed (base temperature=6°C). GDD accumulated during the “flowering – 25 days after flowering” period influenced fatty acid composition of seed. Oleic and linoleic acid contents were affected by accumulated GDD in two HO genotypes (one inbred line and the hybrid). There was an increase of about 3% in oleic acid content as response to more high GDD accumulated. Their content was not modified by GDD in the other inbred line. There was a genotype×environment interaction that we suppose depending on modifier genes. These genetic factors affected oleic acid content. This indicated the importance of breeding targeted to select hybrids with a stable oleic acid content and higher than 90%. Saturated fatty acids (palmitic and stearic) were also influenced by temperature, and there was genetic variability among genotypes.


1975 ◽  
Vol 53 (6) ◽  
pp. 698-705 ◽  
Author(s):  
J. G. Parkes ◽  
W. Thompson

Phosphatidylethanolamine from mitochondria and microsomes of guinea pig liver was separated by thin-layer chromatography into eight different classes differing in degree of unsaturation. The fatty acid compositions and molar proportions of each class isolated from microsomes were very similar to the corresponding class in mitochondria. In both organelles about half of the total was dienoic species while tetraenes comprised approximately 20%. Stearic acid was the major saturated fatty acid and in each membrane a greater selectivity for stearate over palmitate was found in each sub-class of phosphatidylethanolamine, when compared with the corresponding class of phosphatidylcholine.Following the intraperitoneal injection of [2-3H]glycerol, the labelling of each molecular class of phosphatidylethanolamine showed very similar progressions in microsomes and mitochondria over a 3 h interval. In both organelles the highest relative specific activity was attained by penta-plus hexaenoic classes, while the large dienoic class had the lowest relative activity, which, however, increased with time. Analysis of the dienoic class of phosphatidylethanolamine from whole liver showed it to be constituted by a rapidly turning over palmitoyl–linoleoyl fraction and a slowly labelled stearoyl–linoleoyl fraction, a pattern also exhibited by dienoic phosphatidylcholines.The similarities in profile of molecular classes of phosphatidylethanolamine and in the kinetics of labelling in vivo point to a close metabolic relation between the lipids of both organelles, suggestive of a transfer of different molecular classes at comparable rates from the endoplasmic reticulum, the site of synthesis, to the mitochondria. This is consistent with numerous other studies in vitro that have demonstrated inter-organelle exchange of lipids.


2001 ◽  
Vol 280 (3) ◽  
pp. H1222-H1231 ◽  
Author(s):  
X. F. Figueroa ◽  
A. D. Martínez ◽  
D. R. González ◽  
P. I. Jara ◽  
S. Ayala ◽  
...  

To assess the hypothesis that microvascular nitric oxide (NO) is critical to maintain blood flow and solute exchange, we quantified NO production in the hamster cheek pouch in vivo, correlating it with vascular dynamics. Hamsters (100–120 g) were anesthetized and prepared for measurement of microvessel diameters by intravital microscopy, of plasma flow by isotopic sodium clearance, and of NO production by chemiluminescence. Analysis of endothelial NO synthase (eNOS) location by immunocytochemistry and subcellular fractionation revealed that eNOS was present in arterioles and venules and was 67 ± 7% membrane bound. Basal NO release was 60.1 ± 5.1 pM/min ( n = 35), and plasma flow was 2.95 ± 0.27 μl/min ( n = 29). Local NO synthase inhibition with 30 μM N ω-nitro-l-arginine reduced NO production to 8.6 ± 2.6 pmol/min (−83 ± 5%, n = 9) and plasma flow to 1.95 ± 0.15 μl/min (−28 ± 12%, n = 17) within 30–45 min, in parallel with constriction of arterioles (9–14%) and venules (19–25%). The effects of N ω-nitro-l-arginine (10–30 μM) were proportional to basal microvascular conductance ( r = 0.7, P < 0.05) and fully prevented by 1 mM l-arginine. We conclude that in this tissue, NO production contributes to 35–50% of resting microvascular conductance and plasma-tissue exchange.


Agronomy ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 222 ◽  
Author(s):  
Qinfu Sun ◽  
Jueyi Xue ◽  
Li Lin ◽  
Dongxiao Liu ◽  
Jian Wu ◽  
...  

Rapeseed (Brassica napus L.) with substantial lipid and oleic acid content is of great interest to rapeseed breeders. Overexpression of Glycine max transcription factors Dof4 and Dof11 increased lipid accumulation in Arabidopsis and microalgae, in addition to modifying the quantity of certain fatty acid components. Here, we report the involvement of GmDof4 and GmDof11 in regulating fatty acid composition in rapeseeds. Overexpression of GmDof4 and GmDof11 in rapeseed increased oleic acid content and reduced linoleic acid and linolenic acid. Both qPCR and the yeast one-hybrid assay indicated that GmDof4 activated the expression of FAB2 by directly binding to the cis-DNA element on its promoters, while GmDof11 directly inhibited the expression of FAD2. Thus, GmDof4 and GmDof11 might modify the oleic acid content in rapeseed by directly regulating the genes that are associated with fatty acid biosynthesis.


1989 ◽  
Vol 258 (2) ◽  
pp. 541-545 ◽  
Author(s):  
R Reiter ◽  
R Otter ◽  
A Wendel

Selenium (Se)-deficient mice were labelled in vivo with single pulses of [75Se]selenite, and the intrahepatic distribution of the trace element was studied by subcellular fractionation. At 1 h after intraperitoneal injection of 3.3 or 10 micrograms of Se/kg body weight, 15% of the respective doses were found in the liver. Accumulation in the subcellular fractions followed the order: Golgi vesicular much greater than lysosomal greater than cytosolic = microsomal greater than mitochondrial, peroxisomal, nuclear and plasma-membrane fraction. At a dose of 3.3 micrograms/kg, more than 90% of the hepatic Se was protein-bound. When cross-contamination was accounted for, the following specific Se contents of the subcellular compartments were extrapolated: Golgi apparatus, 7.50 pmol/mg; cytosol, 0.90 pmol/mg; endoplasmic reticulum, 0.80 pmol/mg; mitochondria, 0.49 pmol/mg; nuclei, lysosomes, peroxisomes and plasma membrane, less than 0.4 pmol/mg. At 10 micrograms/kg, a roughly 2-3-fold increase in Se content of all fractions was found without major changes in the intrahepatic distribution pattern. An extraordinary rise in the cytosolic fraction was due to an apparently non-protein-bound Se pool. At 24 h after dosing, total hepatic Se had decreased to 6% of the initial dose and had become predominantly protein-bound. The 60% decrease in hepatic Se was reflected in a similar fall in the subcellular levels of the trace element. The Golgi apparatus still had the highest specific Se content, although accumulation was 5 times less than that after 1 h. The cytosolic pool accounted for 50% of the hepatic Se at both labelling times. After 1 h the Golgi apparatus was, with 19%, the second largest intrahepatic pool, followed by the endoplasmic reticulum with 16%. The high affinity and fast response of the Golgi apparatus to Se supplementation of deficient mice is interpreted in terms of a predominant function of this cell compartment in the processing and the export of Se-proteins from the liver.


1979 ◽  
Vol 178 (2) ◽  
pp. 497-500 ◽  
Author(s):  
R F Irvine ◽  
A J Letcher ◽  
R M Dawson

The hydrolysis of membrane-bound phosphatidylinositol in rat liver microsomal fraction by the soluble phosphatidylinositol phosphodiesterase from rat brain was markedly stimulated by oleic acid or arachidonic acid. The stimulation did not require added calcium, although it was abolished by EDTA. Lysophosphatidylcholine also totally suppressed the stimulation. A possible role for the fatty acid content of a membrane in controlling phosphatidylinositol turnover is suggested.


1966 ◽  
Vol 30 (1) ◽  
pp. 73-96 ◽  
Author(s):  
Gustav Dallner ◽  
Philip Siekevitz ◽  
George E. Palade

The development of the endoplasmic reticulum of rat hepatocytes was studied during a period of rapid cell differentiation, i.e., from 3 days before to 8 days after birth. Before birth, the ER increases in volume, remaining predominantly rough surfaced; after birth, the increase continues but affects mainly the smooth-surfaced part of the system. These changes are reflected in variations of the RNA/protein and PLP/protein ratios of microsomal fractions: the first decreases, while the second increases, with age. The analysis of microsomal membranes and of microsomal lipids indicates that the PLP/protein ratio, the distribution of phospholipids, and the rate of P32 incorporation into these phospholipids show little variation over the period examined and are comparable to values found in adult liver. Fatty acid composition of total phosphatides undergoes, however, drastic changes after birth. During the period of rapid ER development in vivo incorporation of leucine-C14 and glycerol-C14 into the proteins and lipids of microsomal membranes is higher in the rough-than in the smooth-surfaced microsomes, for the first hours after the injection of the label; later on (∼10 hr) the situation is reversed. These results strongly suggest that new membrane is synthesized in the rough ER and subsequently transferred to the smooth ER.


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