Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Androgens have profound effects on the physiology of the sebaceous gland. Using the hamster ear sebaceous gland model, we performed a detailed kinetic study to clarify the mechanism of androgen action on sebaceous gland function. We demonstrated that the growth of sebaceous glands observed after androgen treatment was due to both an increase in sebocyte proliferation and a parallel induction of sebocyte terminal differentiation, as evidenced by the induction of the synthesis of specific sebaceous lipids such as cholesterol esters, triglycerides, and squalene. Accordingly, the effect of androgen treatment on the mRNA expression of several key enzymes involved in the synthesis of sebaceous lipids has been studied using semi-quantitative RT-PCR. Up-regulation by androgens of mRNA expression of HMG coenzyme A synthase and reductase, acetyl coenzyme A carboxylase (ACC), glycerol 3-phosphate acyl transferase (GPAT), and FAR-17c (stearoyl coenzyme A desaturase homologous), was demonstrated. Because sterol-response element(s) (SREs) are known to be present in the promoters of these genes, we analyzed the expression by RT-PCR and the activation of the transcription factor sterol regulatory element binding protein (SREBP) using immunoblotting experiments. Our results showed that SREBP-1 was up-regulated and rapidly activated after androgen treatment. Altogether, these results demonstrate for the first time that in sebaceous glands, in vivo, androgen regulates the synthesis of sebum lipids through the SREBP pathway.
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PMID:Involvement of the SREBP pathway in the mode of action of androgens in sebaceous glands in vivo. 1293 Mar 6

Direct analysis of membrane lipids by liquid chromatography-electrospray mass spectrometry was used to demonstrate the role of unsaturation in ether lipids in the adaptation of Methanococcoides burtonii to low temperature. A proteomics approach using two-dimensional liquid chromatography-mass spectrometry was used to identify enzymes involved in lipid biosynthesis, and a pathway for lipid biosynthesis was reconstructed from the M. burtonii draft genome sequence. The major phospholipids were archaeol phosphatidylglycerol, archaeol phosphatidylinositol, hydroxyarchaeol phosphatidylglycerol, and hydroxyarchaeol phosphatidylinositol. All phospholipid classes contained a series of unsaturated analogues, with the degree of unsaturation dependent on phospholipid class. The proportion of unsaturated lipids from cells grown at 4 degrees C was significantly higher than for cells grown at 23 degrees C. 3-Hydroxy-3-methylglutaryl coenzyme A synthase, farnesyl diphosphate synthase, and geranylgeranyl diphosphate synthase were identified in the expressed proteome, and most genes involved in the mevalonate pathway and processes leading to the formation of phosphatidylinositol and phosphatidylglycerol were identified in the genome sequence. In addition, M. burtonii encodes CDP-inositol and CDP-glycerol transferases and a number of homologs of the plant geranylgeranyl reductase. It therefore appears that the unsaturation of lipids may be due to incomplete reduction of an archaeol precursor rather than to a desaturase mechanism. This study shows that cold adaptation in M. burtonii involves specific changes in membrane lipid unsaturation. It also demonstrates that global methods of analysis for lipids and proteomics linked to a draft genome sequence can be effectively combined to infer specific mechanisms of key biological processes.
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PMID:Cold adaptation in the Antarctic Archaeon Methanococcoides burtonii involves membrane lipid unsaturation. 1557 1

In this study, we demonstrate that B-type natriuretic peptide (BNP) opposed angiotensin II (Ang II)-stimulated de novo cholesterol biosynthesis, cellular cholesterol uptake, cholesterol transfer to the inner mitochondrial membrane, and steroidogenesis, which are required for biosynthesis of steroid hormones such as aldosterone and cortisol in primary human adrenocortical cells. BNP dose-dependently stimulated intracellular cGMP production with an EC(50) of 11 nm, implying that human adrenocortical cells express the guanylyl cyclase A receptor. cDNA microarray and real-time RT-PCR analyses revealed that BNP inhibited Ang II-stimulated genes related to cholesterol biosynthesis (acetoacetyl coenzyme A thiolase, HMG coenzyme A synthase 1, HMG coenzyme A reductase, isopentenyl-diphosphate Delta-isomerase, lanosterol synthase, sterol-4C-methyl oxidase, and emopamil binding protein/sterol isomerase), cholesterol uptake from circulating lipoproteins (scavenger receptor class B type I and low-density lipoprotein receptor), cholesterol transfer to the inner mitochondrial membrane (steroidogenic acute regulatory protein), and steroidogenesis (ferredoxin 1,3beta-hydroxysteroid dehydrogenase, glutathione transferase A3, CYP19A1, CYP11B1, and CYP11B2). Consistent with the microarray and real-time PCR results, BNP also blocked Ang II-induced binding of (125)I-labeled low-density lipoprotein and (125)I-labeled high-density lipoprotein to human adrenocortical cells. Furthermore, BNP markedly inhibited Ang II-stimulated release of estradiol, aldosterone, and cortisol from cultured primary human adrenocortical cells. These findings demonstrate that BNP opposes Ang II-induced steroidogenesis via multiple steps from cholesterol supply and transfer to the final formation of steroid hormones. This study provides new insights into the cellular mechanisms by which BNP modulates Ang II-induced steroidogenesis in the adrenal gland.
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PMID:B-Type natriuretic peptide inhibited angiotensin II-stimulated cholesterol biosynthesis, cholesterol transfer, and steroidogenesis in primary human adrenocortical cells. 1747 52