Sphingomyelin (SM) is a ceramide linked with phosphocholine, and is found in nerves of vertebrate, especially myelin sheath. The long-chain base of SM is mostly d18:1 and some d18:0, just like glycosphingolipid. Fatty acid components are length 16-24 and hydroxy fatty acids are not included.[1]
Sphingomyelin synthase is classified into three groups (SMS1, SMS2, SMSr), and two of them synthesize SM at Golgi (SMS1) and plasma membrane (SMS2). In mammals, a protein called CERT transports ceramide from ER to Golgi to synthesize SM.
For degradation of SM, many enzymes are known that function in acidic, neutral, or alkaline conditions.[2]
SM involves in cellular absorption of transferrin, cancer, and arterial sclerosis. Niemann-Pick disease type A / B, an inborn metabolic disease, is caused by accumulation of SM through the shortage of acid sphingomyelinase.[3]
↑Merrill, A.H. "Sphingolipid and Glycosphingolipid Metabolic Pathways in the Era of Sphingolipidomics" Chem. Rev. 2011, 111, 6387–6422. PMID 21942574
↑Gault CR, Obeid LM, Hannun YA. "An overview of sphingolipid metabolism: from synthesis to breakdown" Adv Exp Med Biol. 2010;688:1-23. PMID 20919643, Yamaji T, Hanada K. "Sphingolipid metabolism and interorganellar transport: localization of sphingolipid enzymes and lipid transfer proteins" Traffic 2015 16:101-22.PMID 25382749 Zhang Y, Cheng Y, Hansen GH, Niels-Christiansen LL, Koentgen F, Ohlsson L, Nilsson A, Duan RD. "Crucial role of alkaline sphingomyelinase in sphingomyelin digestion: a study on enzymeknockout mice" J Lipid Res. 2011 52:771-81 PMID 21177474
↑Slotte JP. "Biological functions of sphingomyelins" Prog Lipid Res. 2013; 52:424-37.PMID 23684760, Horinouchi K, Erlich S, Perl DP, Ferlinz K, Bisgaier CL, Sandhoff K, Desnick RJ, Stewart CL, Schuchman EH. "Acid sphingomyelinase deficient mice: a model of types A and B Niemann−Pick disease" Nat Genet. 1995;10:288-93. PMID 7670466
CPE and CAEP
Ceramide phosphoethanolamine (CPE) is formed from a ceramide phosphate linked with ethanolamine. It is often found in insects, trace amount in many animals including bacteria, protozoa, and mammals, and absent in plants or fungi.[1]
Ceramide aminoethylphosphonate (CAEP) is similar to CPE but is formed by the C-P bonding. It is found in protozoa, cnidaria, mollusca, and echinodermata.[2]
There exist three types of sphingomyelin synthase, two of which synthesize CPE. One is SM synthase 2 in cell- and golgi membranes and the other, SM synthase-like protein in the ER lumen (CPE synthase). [3]
↑Bhat HB, Ishitsuka R, Inaba T, Murate M, Abe M, Makino A, Kohyama-Koganeya A, Kurahashi A, Kishimoto T, Tahara M, Yamamo A, Nagamune K, Hirabayashi Y, Juni N, Umeda M, Fujimori F, Nishibori K, Yamaji A, Greimel P, Kobayashi T, Evaluation of aegerolysins as novel tools to detect and visualize ceramide phosphoethanolamine, a major sphingolipid in invertebrates, FASEB J. 2015 29:3920-34.PMID 26060215 Hannich JT, Umebayashi K, Riezman H. Distribution and functions of sterols and sphingolipids. Cold Spring Harb Perspect Biol. 2011 3. pii: a004762.PMID 21454248
↑Hori T, Itasaka O, Inoue H. Biochemistry of shellfish lipid. 3. Purification and elemental analysis of ceramide aminoethylphosphonate from Corbicula complex lipid mixtures. J Biochem. 1966 59:570-3. PMID 5962677
↑Ternes P, Brouwers JF, van den Dikkenberg J, Holthuis JC. “Sphingomyelin synthase SMS2 displays dual activity as ceramide phosphoethanolaminesynthase”J Lipid Res. 2009; 50:2270-7. PMID 19454763
GIPC
Glycosyl inositol phosphoceramides (GIPCs) were historically referred to as 'phytoglycolipids' (PGLs) for their abundance in plants and fungi.[1][2]
Later found in bacteria, protista, and other animals (except chordata), PGLs are now called GIPCs. The structure is composed of ceramide with inositol phosphate (inositolphosphoceramide, IPC) and different sugars are attached.[3][4]
Classification
In LipidBank, we classify GIPC into four types:
P2 series: Glucosamine next to inositol (Fungi and Protista)
P3 series: Glucuronic acid next to inositol (Plant)
↑Carter HE, Celmer WD, Galanos DS, Gigg RH, Lands EM, Law JH, Mueller KL, Nakayama T, Tomizawa HH, Weber E. Biochemistry of the sphingolipides. X. Phytoglycolipide, a complex phytosphingosine-containing lipide from plant seeds. Journal of the American Oil Chemists Society 1958 35: 335–343 DOI 10.1007/BF02640547
↑Carter HE, Kisic A. “Countercurrent distribution of inosol lipids of plant seeds” J Lipid Res. 1969; 10:356-62. PMID 4307829
↑Buré C, Cacas JL, Mongrand S, Schmitter JM "Characterization of glycosyl inositol phosphoryl ceramides from plants and fungi by mass spectrometry" Anal Bioanal Chem. 2014 406:995-1010. PMID 23887274
↑Gronnier J, Germain V, Gouguet P, Cacas JL, Mongrand S. ”GIPC: Glycosyl Inositol Phospho Ceramides, the major sphingolipids on earth”Plant Signal Behav. 2016 2;11(4):e1152438 PMID 27074617
↑Zhong W, Murphy DJ, Georgopapadakou NH. “Inhibition of yeast inositol phosphorylceramide synthase by aureobasidin A measured by afluorometric assay” FEBS Lett. 1999; 17;463:241-4. PMID 10606729
Sphingolipids in All Kingdoms
The table lists biological species from which sphingolipids were identified. Icons indicate representative species. The icons are used in sphingolipid references together with for chemical synthesis.
