Sphingolipid

Sphingolipids are important components of cell membrane and belong to the class of compounds of the lipids. In contrast to the building on the glycerol phosphoglycerides, sphingolipids are derived from the unsaturated amino alcohol sphingosine.

Through its amine group, the sphingosine is amidically connected with an acyl group such as a fatty acid. The sphingosine backbone is charged via a phosphate moiety by ester bonds with a (usually ) group such as serine, ethanolamine or choline connected. If it is at the head group is one or more sugars, the bonding is carried out directly without a phosphate group on the sphingosine backbone by a glycosidic bond.

Sphingolipids are often found in nervous tissue, where they play an important role in signal transduction and interaction of individual cells.

Classes of sphingolipids

There are three main types of sphingolipids: ceramides and sphingomyelins and glycosphingolipids derived therefrom. The latter are further divided into cerebrosides and gangliosides. These types differ in their type of residue ( see image ). Ceramides are the easiest group of sphingolipids. For them, the rest is formed by only one hydrogen atom, so they are only a Sphingosinmolekül that is bound by an amide bond to a fatty acid. Sphingomyelins have a phosphocholine or Phosphoethanolaminmolekül bound as esters at the 1 -hydroxyl group of ceramides. Glycosphingolipids are ceramides with one or more sugar residues which are bound by a β - glycosidic linkage to the 1- hydroxy group. Cerebrosides have a single glucose or galactose molecule, the balance while Gangliosides contain at least three sugars, of which at least one sialic acid.

Sphingolipids are synthesized in the endoplasmic reticulum and the Golgi apparatus, but are in the plasma membrane and in endosomes, where they fulfill numerous tasks, further worked. Your transport via vesicles. In the mitochondria and the endoplasmic reticulum sphingolipids are virtually undetectable in the plasma membrane, but its concentration is 20-35 mol %.

Biological Function

The major lipids in eukaryotic cell membrane include glycerophospholipids, cholesterol and sphingolipids ( phospho- and glycosphingolipids ). Their functions can be described on the one about the structure and the regulation of fluidity of cellular membranes and on the other in the explanation of intercellular recognition processes (see metazoan ). In the clinical and medical application the analysis is used to characterize the development-specific markers but also as a tumor, as well as blood group antigens.

Mid -1980s it was discovered that inhibition of protein kinase C ( PKC) by sphingosine. This led to the idea that sphingolipids can also act as intracellular messengers, as so-called second messengers. In the center of current research interest are the sphingolipids ceramide and ceramide - 1-phosphate and sphingosine and sphingosine -1 -phosphate.