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.
Glycogenin is an enzyme involved in converting glucose to glycogen. It acts as a primer, by polymerizing the first few glucose molecules, after which other enzymes take over. It is a homodimer of 37-kDa subunits and is classified as a glycosyltransferase.
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.
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.
Ceramide glucosyltransferase is a glucosyltransferase enzyme involved in the production of glucocerebroside.
In enzymology, a globotriaosylceramide 3-beta-N-acetylgalactosaminyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a lactosylceramide 4-alpha-galactosyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a sucrose synthase is an enzyme that catalyzes the chemical reaction
5'-AMP-activated protein kinase catalytic subunit alpha-1 is an enzyme that in humans is encoded by the PRKAA1 gene.
5'-AMP-activated protein kinase subunit beta-1 is an enzyme that in humans is encoded by the PRKAB1 gene.
Reticulon-3 is a protein that in humans is encoded by the RTN3 gene.
Hyaluronan synthase 2 is an enzyme that in humans is encoded by the HAS2 gene.
Reticulon-1 also known as neuroendocrine-specific protein (NSP) is a protein that in humans is encoded by the RTN1 gene.
Alpha-N-acetylneuraminide alpha-2,8-sialyltransferase is an enzyme that in humans is encoded by the ST8SIA1 gene.
Beta-1,4 N-acetylgalactosaminyltransferase 1 is an enzyme that in humans is encoded by the B4GALNT1 gene.
Lactosylceramide 4-alpha-galactosyltransferase is an enzyme that in humans is encoded by the A4GALT gene.
(N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase is an enzyme with systematic name UDP-N-acetyl-D-galactosamine:1-O-(O- - -O-beta-D-galactopyranosyl- -beta-D-glucopyranosyl)-ceramide 4-beta-N-acetyl-D-galactosaminyltransferase. This enzyme catalyses the following chemical reaction:
Glucosylceramide beta-1,4-galactosyltransferase is an enzyme with systematic name UDP-alpha-D-galactose:beta-D-glucosyl-(1<->1)-ceramide 4-beta-D-galactosyltransferase. This enzyme catalyses the following chemical reaction
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 5 (CerS5) is the enzyme encoded in humans by the CERS5 gene.
