The 26S proteasome is involved in the ATP-dependent degradation of ubiquitinated proteins. The regulatory (or ATPase) complex confers ATP dependency and substrate specificity to the 26S complex (By similarity). May play a role in the degradation of microtubule severing protein mei-1 (PubMed:22621901). RNAi-mediated knockdown at the L1 larval stage, causes 20 percent increase in mei-1 protein levels. Belongs to the AAA ATPase family.