Ceramide channel: Structural basis for selective membrane targeting. (January 2016)

• Record Type: Journal Article
• Authors: Perera, Meenu N.; Ganesan, Vidyaramanan; Siskind, Leah J.; Szulc, Zdzislaw M.; Bielawska, Alicja; Bittman, Robert; Colombini, Marco
• Is Part Of: Chemistry and physics of lipids. Volume 194:(2016)
• Page Start: 110
• Page End: 116
• Publication Date: 2016-01
• Subjects: Ceramide channel -- Analog -- Sphingolipid; -- Erythrocyte -- Mitochondria; Lipids -- Periodicals; Lipids -- Periodicals; Lipides -- Périodiques; Lipids; Periodicals; Electronic journals; 547.77
• DOI: 10.1016/j.chemphyslip.2015.09.007
• Languages: English
• ISSNs: 0009-3084

Abstract

Graphical abstract: Highlights: Ceramide selectively permeabilizes the mitochondrial outer membrane. Ceramide does not permeabilize the erythrocyte plasma membrane. Relatively small structural changes allow the ceramide analog to permeabilize the plasma membrane of erythrocytes. The mirror image molecule of ceramide permeabilizes the erythrocyte plasma membrane. An unknown mechanism prevents ceramide generation in the plasma membrane from forming channels and thus killing the cell. Abstract: A ceramide commonly found in mammalian cells, C16 -ceramide ( N -palmitoyl-d -erythro-sphingosine), is capable of forming large, protein-permeable channels in the mitochondrial outer membrane (MOM). However, C16 -ceramide is unable to permeabilize the plasma membrane of erythrocytes. This specificity is unexpected considering that ceramide forms channels in simple phosphoglycerolipid membranes. Synthetic analogs of C16 -ceramide with targeted changes at each of the functional regions of the molecule including methylation, altered hydrocarbon chain length, and changes in the stereochemistry, were tested to probe the role of ceramide's molecular features on its ability to form channels in these two different membrane types. The ability to permeabilize the MOM was relatively insensitive to modifications of the various functional groups of ceramide whereas the same modifications resulted in plasma membrane permeabilization (a gain of function rather than a loss of function). Some analogs (ceramine, NBD-labeled ceramide, C18, 1 ceramide) gained another function, the ability to inhibit cytochrome oxidase. The gain of deleterious functions indicates that constraints on the structure of ceramide that is formed by the cell's synthetic machinery includes the avoidance of deleterious interactions. We propose that the specific structure of ceramide limits the size of its interactome (both proteins and lipids) thus reducing the likelihood of unwanted side effects.