exosome

The exosome complex consists almost exclusively of exoribonucleolytic proteins -- 10 different proteins important for 3'– > 5' degradation of ARE-containing mRNAs in mammalian cells. Although exosomes accumulate in the nucleolus, they also localize in the cytoplasm and in neoplasm. The exosome membrane is organized as a lipid bilayer with a random distribution of phosphatidylethanolamines. Exosome membranes display a similar content of the major phospholipids and cholesterol, but an enrichment in sphingomyelin when compared to the parent cell membrane.

Review Exosome & Models of exosome complex.

Edinburgh Research Archive : Item 1842/734: "The exosome complex of 3' -> 5' exoribonucleases functions in both the precise processing of 3' extended precursor molecules to mature stable RNAs and the complete degradation of other RNAs. Both processing and degradative activities of the exosome depend on additional cofactors, notably the putative RNA helicases Mtr4p and Ski2p. "

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