Mitochondrial Dysfunction and Barth Syndrome
Shamim I. Ahmad in Handbook of Mitochondrial Dysfunction, 2019
In eukaryotes, most phospholipids are synthesized in the endoplasmic reticulum (ER); however, the biosynthetic pathway of CL occurs exclusively in the mitochondrion37,38. This multi-step process, elucidated over the past 40 years, begins with the generation of phosphatidic acid (PA), which can be potentially sourced from several pathways6. PA, synthesized in the ER, on the outer surface of the OMM, or in the IMS, is then transported to the matrix side of the IMM where a condensation reaction between PA and cytidine triphosphate (CTP), catalyzed by Tam41p (Human Gene Organization (HUGO) Gene Nomenclature Committee (HGNC): TAMM41, Saccharomyces Genome Database (SGD): TAM41), forms cytidine diphosphate diacylglycerol (CDP-DAG)6,39,40. CDP-DAG and glycerol-3-phosphate (G3P) are then converted to phosphatidylglycerol phosphate (PG-P) by PG-P synthase (HGNC: PGS1, SGD: PGS1)41,42. PG-P is rapidly dephosphorylated to PG by PG-P phosphatase (HGNC: PTPMT1, SGD: GEP4)43,44. PG is then bound to another molecule of CDP-DAG by CL synthase (HGNC: CRLS1, SGD: CRD1), an integral IMM protein whose active site faces the mitochondrial matrix, through a condensation reaction that forms nascent CL (Figure 2)45–48.
Fetal Circulation
Miriam Katz, Israel Meizner, Vaclav Insler in Fetal Well-Being, 2019
The de novo production of PC requires phosphorylation of choline, which is activated by conversion of choline phosphate to cytidine diphosphate derivative and then the transfer of the phosphorylcholine portion of the active compound to diglyceride. The described pathway of PC synthesis is the cytidine diphosphate choline pathway (CDP).39 This pathway is stable and not affected by changes in the fetal milieu, such as hypothermia, hypoxia, or acidosis. The CDP pathway is found to produce surfactant only from week 36 of pregnancy onward. Prior to week 36, lecithin is produced mainly by methylation. The methylation pathway is a process during which the phosphatidyl ethanolamine is bound to the diglyceride and thereafter undergoes methylation. This pathway of surfactant biosynthesis is easily affected by changes in the fetal homeostasis. The methylation pathway is known to be active as early as week 18 of gestation.
Emerging ergogenic aids for strength/power development
Jay R Hoffman in Dietary Supplementation in Sport and Exercise, 2019
Phosphatidylethanolamine (PE) is another phospholipid found in biological cell membranes most concentrated in the internal leaflet and is abundant in the mitochondria. It has similarities in structure to other phospholipids but has ethanolamine combined with its phosphate group (Figure 14.7). PE accounts for 20–30% of phospholipid pool (9). It is synthesized via decarboxylation of PS (by the actions of PS decarboxylase) and by the addition of cytidine diphosphate-ethanolamine to diglycerides. PE can also form PC via methylation from SAM. Some dietary sources of PE include beef, chicken, eggs, pork, soybeans, whole milk, peanuts, tuna, salmon and other fish (9, 14). Endurance athletes have been shown to have significantly higher PE content in skeletal muscle suggesting that chronic endurance training may up-regulate PE (45). Acute exercise appears to have no effect on muscle PE; however, significant reduction in muscle PE have been reported in endurance athletes two hours post exercise (45).
Ameliorative effect of myo-inositol on red blood cell alterations in polycystic ovary syndrome: in vitro study
Published in Gynecological Endocrinology, 2018
Alessandra Andrisani, Gabriella Donà, Chiara Sabbadin, Elena Tibaldi, Francesco Dessole, Valentina Bosello Travain, Loris Marin, Anna Maria Brunati, Guido Ambrosini, Decio Armanini, Eugenio Ragazzi, Luciana Bordin
(i) RBC, previously described as lacking the enzyme needed for the de novo synthesis of PI leading to the condensation of MYO with cytidine-diphosphate-diacylglycerol (CDP-DAG) [28], recently have been shown to incorporate MYO also at 30 min, but without forming PI in the absence of additional CTP-DAG [29]. We can argue that in 24 h a sort of MYO incorporation could have occurred but also additional studies are required to estimate the effective de novo synthesis of PI. PI is the precursor of both phosphatidyl (PIs) and glycosyl phosphatidyl inositols (GPIs) synthesis, commonly taking place between endoplasmic reticulum and Golgi apparatus [30]. If PIs are considered the second messengers inside the cells, insulin-activated phospholipase D gives birth to GPI derivatives, the inositol glycan second messenger (INS-2), which can also be yielded in the outer membrane surface of the cell and modulate insulin action [30], thus potentiating insulin effects and reducing the insulin resistance.
New approved and emerging pharmacological approaches to alcohol use disorder: a review of clinical studies
Published in Expert Opinion on Pharmacotherapy, 2021
Kirsten C Morley, Christina J Perry, Joshua Watt, Tristan Hurzeler, Lorenzo Leggio, Andrew J Lawrence, Paul Haber
Citicoline (cytidine diphosphate-choline) is a widely available supplement with a favorable side effect profile. Citicoline functions as a metabolite and precursor of acetylcholine and is also an essential component of cell membrane phospholipids [69] and thus plays an important role in neuronal structure and signaling [70]. Studies have demonstrated that in methamphetamine-dependent individuals, citicoline administration is associated with increased levels of prefrontal N-acetyl-aspartate (NAA) [71], which is a marker of neuronal viability and has been shown to correlate with poor cognitive functioning in heavy drinkers [72].
Related Knowledge Centers
- Cytidine
- Cytosine
- Ester
- Functional Group
- Nucleobase
- Nucleoside
- Nucleotide
- Pyrophosphate
- Pyrophosphoric Acid
- Sugar