Ceramide at the Plasma Membrane

Abstract

Compared with other lipids, ceramide moves with less frequency between lipid membranes and tends to aggregate into highly enriched ceramide regions. This property plays a large part in determining how ceramide-mediated signals are controlled and generated. Venkataraman and Futerman review how the biological and physical properties of ceramide affect its ability to control signals. Because ceramide does not move very freely within or between lipid bilayers, this implies that ceramide-regulated proteins must localize to enriched ceramide regions at the plasma membrane before full activation and proper signaling context. Although several proteins are known to bind ceramide, no specific ceramide-binding motif has been identified; however, it is thought that cysteine residues have a role in recognizing ceramide. Additionally, the authors review the finding that ceramide appears to be made in the endoplasmic reticulum, as well as in mitochondria, endosomes, and the nuclear membrane. Thus, depending on where ceramide resides in the cell, signaling components may be specifically targeted to those subcellular addresses for compartmentalized signaling. Venkataraman, K, and Futerman, A.H. (2000) Ceramide as a second messenger: Sticky solutions to sticky problems. Trends Cell Biol. 10 : 408-412. [Full Text]