| CERS3 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Aliases | CERS3 , ARCI9, LASS3, ceramide synthase 3 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 615276; MGI: 2681008; HomoloGene: 18719; GeneCards: CERS3; OMA:CERS3 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Ceramide synthase 3 (CersS3), also known as longevity assurance homologue 3, is an enzyme that is encoded in humans by the CERS3 gene.
CerS3 synthesizes C24-ceramides and ceramides with longer acyl chains, and is found mainly in skin and testis. [5] Specifically, CerS3 synthesizes ceramides containing α-hydroxy (2-hydroxy) fatty acids, which are abundant in skin tissue, where they help maintain the water permeability barrier qualities of the skin. [6] It is found in large quantities in keratinocytes, and this increases during keratinocyte differentiation. [7]
In the testes, CerS3 is involved in sperm formation and androgen production. [5] Cers3 gene expression is located within germ cells, where it is massively upregulated during juvenile testicular maturation. This upregulation is correlated with increase in levels of glycosphingolipids containing very long chain (C26-C32) polyunsaturated fatty acid (LC-PUFA), which are required for spermatogenesis. [8]
CerS3 (T3l) mRNA is strongly expressed in skin, and was also found in brain, lung and kidney. [9] CerS3 is mainly found in the skin and testes. CerS3 is not detectable in the brain or the sciatic nerve. [10] Like other ceramide synthases, CerS3 is found in the endoplasmic reticulum within the cell. [11]
CerS3 has a molecular mass of 46.2 kDa, 383 amino acids, and six transmembrane domains. Like other ceramide synthases, CerS3 contains a Hox-like domain. [11] CerS3 is the only ceramide synthase for which splice variants have not been reported. [12]
Sphingolipids are a class of lipids containing a backbone of sphingoid bases, which are a set of aliphatic amino alcohols that includes sphingosine. They were discovered in brain extracts in the 1870s and were named after the mythological sphinx because of their enigmatic nature. These compounds play important roles in signal transduction and cell recognition. Sphingolipidoses, or disorders of sphingolipid metabolism, have particular impact on neural tissue. A sphingolipid with a terminal hydroxyl group is a ceramide. Other common groups bonded to the terminal oxygen atom include phosphocholine, yielding a sphingomyelin, and various sugar monomers or dimers, yielding cerebrosides and globosides, respectively. Cerebrosides and globosides are collectively known as glycosphingolipids.
Sphingomyelin is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath that surrounds some nerve cell axons. It usually consists of phosphocholine and ceramide, or a phosphoethanolamine head group; therefore, sphingomyelins can also be classified as sphingophospholipids. In humans, SPH represents ~85% of all sphingolipids, and typically make up 10–20 mol % of plasma membrane lipids.
Fumonisin B1 is the most prevalent member of a family of toxins, known as fumonisins, produced by multiple species of Fusarium molds, such as Fusarium verticillioides, which occur mainly in maize (corn), wheat and other cereals. Fumonisin B1 contamination of maize has been reported worldwide at mg/kg levels. Human exposure occurs at levels of micrograms to milligrams per day and is greatest in regions where maize products are the dietary staple.
Ceramides are a family of waxy lipid molecules. A ceramide is composed of sphingosine and a fatty acid joined by an amide bond. Ceramides are found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer. Contrary to previous assumptions that ceramides and other sphingolipids found in cell membrane were purely supporting structural elements, ceramide can participate in a variety of cellular signaling: examples include regulating differentiation, proliferation, and programmed cell death (PCD) of cells.
Sphingosine kinase (SphK) is a conserved lipid kinase that catalyzes formation sphingosine-1-phosphate (S1P) from the precursor sphingolipid sphingosine. Sphingolipid metabolites, such as ceramide, sphingosine and sphingosine-1-phosphate, are lipid second messengers involved in diverse cellular processes. There are two forms of SphK, SphK1 and SphK2. SphK1 is found in the cytosol of eukaryotic cells, and migrates to the plasma membrane upon activation. SphK2 is localized to the nucleus.
Lipid signaling, broadly defined, refers to any biological cell signaling event involving a lipid messenger that binds a protein target, such as a receptor, kinase or phosphatase, which in turn mediate the effects of these lipids on specific cellular responses. Lipid signaling is thought to be qualitatively different from other classical signaling paradigms because lipids can freely diffuse through membranes. One consequence of this is that lipid messengers cannot be stored in vesicles prior to release and so are often biosynthesized "on demand" at their intended site of action. As such, many lipid signaling molecules cannot circulate freely in solution but, rather, exist bound to special carrier proteins in serum.
Palmitoyl-CoA is an acyl-CoA thioester. It is an "activated" form of palmitic acid and can be transported into the mitochondrial matrix by the carnitine shuttle system, and once inside can participate in beta-oxidation. Alternatively, palmitoyl-CoA is used as a substrate in the biosynthesis of sphingosine.
In enzymology, sphingosine N-acyltransferases (ceramide synthases (CerS), EC 2.3.1.24) are enzymes that catalyze the chemical reaction of synthesis of ceramide:
In enzymology, a 2-hydroxyacylsphingosine 1-beta-galactosyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a ceramide kinase, also abbreviated as CERK, is an enzyme that catalyzes the chemical reaction:
Ceramide glucosyltransferase is an enzyme that in humans is encoded by the UGCG gene.
Serine palmitoyltransferase, long chain base subunit 2, also known as SPTLC2, is a protein which in humans is encoded by the SPTLC2 gene. SPTLC2 belongs to the class-II pyridoxal-phosphate-dependent aminotransferase family.
Epidermis-type lipoxygenase 3 is a member of the lipoxygenase family of enzymes; in humans, it is encoded by the ALOXE3 gene. This gene is located on chromosome 17 at position 13.1 where it forms a cluster with two other lipoxygenases, ALOX12B and ALOX15B. Among the human lipoxygenases, ALOXE3 is most closely related in amino acid sequence to ALOX12B. ALOXE3, ALOX12B, and ALOX15B are often classified as epidermal lipoxygenases, in distinction to the other three human lipoxygenases, because they were initially defined as being highly or even exclusively expressed and functioning in skin. The epidermis-type lipoxygenases are now regarded as a distinct subclass within the multigene family of mammalian lipoxygenases with mouse Aloxe3 being the ortholog to human ALOXE3, mouse Alox12b being the ortholog to human ALOX12B, and mouse Alox8 being the ortholog to human ALOX15B [supplied by OMIM]. ALOX12B and ALOXE3 in humans, Alox12b and Aloxe3 in mice, and comparable orthologs in other in other species are proposed to act sequentially in a multistep metabolic pathway that forms products that are structurally critical for creating and maintaining the skin's water barrier function.
Fatty acid 2-hydroxylase is a protein that in humans is encoded by the FA2H gene.
Very-long-chain 3-oxoacyl-CoA synthase (EC 2.3.1.199, very-long-chain 3-ketoacyl-CoA synthase, very-long-chain beta-ketoacyl-CoA synthase, condensing enzyme, CUT1, CER6, FAE1, KCS, ELO) is an enzyme with systematic name malonyl-CoA:very-long-chain acyl-CoA malonyltransferase (decarboxylating and thioester-hydrolysing). This enzyme catalyses the following chemical reaction
Delta(4)-desaturase, sphingolipid 2 is a protein that in humans is encoded by the DEGS2 gene.
Ceramide synthase 1 also known as LAG1 longevity assurance homolog 1 is an enzyme that in humans is encoded by the CERS1 gene.
Ceramide synthase 2, also known as LAG1 longevity assurance homolog 2 or Tumor metastasis-suppressor gene 1 protein is an enzyme that in humans is encoded by the CERS2 gene.
Ceramide synthase 4 (CerS4) is an enzyme that in humans is encoded by the CERS4 gene and is one of the least studied of the ceramide synthases.
Ceramide synthase 5 (CerS5) is the enzyme encoded in humans by the CERS5 gene.
