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). Component of the 19S proteasome regulatory particle complex. The 26S proteasome consists of a 20S proteasome core and two 19S regulatory subunits. Interacts with Rpn6 (PubMed:22187461). Interacts with imd and Usp2 isoform A (PubMed:25027767). Belongs to the AAA ATPase family.