Sphingomyelin-degrading pathways in human cells role in cell signalling.
The ubiquitous sphingophospholipid sphingomyelin (SM) can be hydrolysed in human cells to ceramide by different sphingomyelinases (SMases). These enzymes exert a dual role, enabling not only the turnover of membrane SM and the degradation of exogenous (lipoprotein) SM, but also the signal-induced generation of the lipid second messenger ceramide. This review focuses on the function(s) of the different SMases in living cells. While both lysosomal and non-lysosomal pathways that ensure SM hydrolysis in intact cells can be distinguished, the precise contribution of each of these SM-cleaving enzymes to the production of ceramide as a signalling molecule remains to be clarified.
Levade
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T
INSERM U. 466, Laboratoire de Biochimie, Maladies Métaboliques, Institut Louis Bugnard, CHU Rangueil, Toulouse, France. levade@rangueil.inserm.fr
Andrieu-Abadie
N
N
Ségui
B
B
Augé
N
N
Chatelut
M
M
Jaffrézou
J P
JP
Salvayre
R
R
D000818:Animals; D002518:Ceramides / Q000096:biosynthesis; D006801:Humans; D015290:Second Messenger Systems / Q000502:physiology*; D013108:Sphingomyelin Phosphodiesterase / Q000502:physiology; D013109:Sphingomyelins / Q000378:metabolism*
D002518:Ceramides; D013109:Sphingomyelins; D013108:Sphingomyelin Phosphodiesterase