An analysis of the Caenorhabditis elegans lipid raft proteome using geLC-MS/MS

Lipid rafts are microdomains of the phospholipid bilayer, proposed to form semi-stable "islands" that act as a platform for several important cellular processes; major classes of raft-resident proteins include signalling proteins and glycosylphosphatidylinositol (GPI)-anchored proteins. Proteomic studies into lipid rafts have been mainly carried out in mammalian cell lines and single cell organisms. The nematode Caenorhabditis elegans, the model organism with a well-defined developmental profile, is ideally suited for the study of this subcellular locale in a complex developmental context. A study of the lipid raft proteome of C. elegans is presented here. A total of 44 proteins were identified from the lipid raft fraction using geLC-MS/MS, of which 40 have been determined to be likely raft proteins after analysis of predicted functions. Prediction of GPI-anchoring of the proteins found 21 to be potentially modified in this way, two of which were experimentally confirmed to be GPI-anchored. This work is the first reported study of the lipid raft proteome in C. elegans. The results show that raft proteins, including numerous GPI-anchored proteins, may have a variety of potentially important roles within the nematode, and will hopefully lead to C. elegans becoming a useful model for the study of lipid rafts.