Does anyone know if ubiquitin-independent protein degradation by the 20S proteasome exists in C. elegans and if so, to what extent? I am specifically interested in what proportion of proteins get degraded by ubiquitin-independent vs. ubiquitin-dependent pathway and whether this changes with age in C. elegans. I found a lot of literature on this topic in mammals and in cell culture, but cannot find anything specific to C. elegans. Thank you.