A protein-protein interaction map of the Caenorhabditis elegans 26S proteasome

The ubiquitin-proteasome proteolytic pathway is pivotal in most biological processes. Despite a great level of information available for the eukaryoti c 26S proteasome-the protease responsible for the degradation of ubiquityla ted proteins-several structural and functional questions remain unanswered. To gain more insight into the assembly and function of the metazoan 26S pr oteasome, a two-hybrid-based protein interaction map was generated using 30 Caenorhabditis elegans proteasome subunits. The results recapitulate inter actions reported for other organisms and reveal new potential interactions both within the 19S regulatory complex and between the 19S and 20S subcompl exes. Moreover, novel potential proteasome interactors were identified, inc luding an E3 ubiquitin ligase, transcription factors, chaperone proteins an d other proteins not yet functionally annotated. By providing a wealth of n ovel biological hypotheses, this interaction map constitutes a framework fo r further analysis of the ubiquitin-proteasome pathway in a multicellular o rganism amenable to both classical genetics and functional genomics.