[
International Worm Meeting,
2015]
The nematode surface coat is the outermost layer that sits at the interface of the worm cuticle and the environment. This coat is continuously synthesized and shed, in contrast to the cuticle itself, which is shed at each molt. Its dynamic nature allows the nematode to respond to different environmental stimuli. In parasitic nematodes, the surface coat mediates interactions between parasites and their hosts. Previous biochemical and genetic studies show that the surface coat glycosylation pattern affects surface properties and the nematode's susceptibility to pathogens. The relative low protein abundance of the surface coat when compared to the total worm proteome has made it difficult to characterize its composition. We have developed a protocol to isolate an excreted-secreted protein (ESP) fraction by collecting and concentrating the spent media from synchronized large-scale C. elegans cultures. Using high-throughput liquid chromatography/ mass spectrometry analysis, we discovered that the C. elegans ESP fraction contains C-type lectins domain-containing proteins, proteases, antimicrobial proteins and lysozymes. Many ESP protein components have been previously identified as transcriptionally upregulated upon pathogen exposure, which agrees with the innate immune response role assigned to some of these proteins. In addition, many uncharacterized proteins were found in this preparation, including nematode-specific proteins. Ongoing efforts include the characterization of the surface proteomes of mutants with surface glycosylation defects. This study will contribute to our understanding of how pathogen recognition and defense mechanisms occurs at the surface coat level and provide insight on glycoproteins that could be key players in parasitic nematodes-host interactions.