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 form a homodimer or a heterodimer with a related family member. Interacts with OLA1, TMA17, and UBR1. N-acetylated by NAT1. Present with 4700 molecules/cell in log phase SD medium. Belongs to the AAA ATPase family.