Associated component of the proteasome that specifically recognizes acetylated histones and promotes ATP- and ubiquitin-independent degradation of core histones during DNA damage response. Recognizes and binds acetylated histones via its bromodomain-like (BRDL) region and activates the proteasome by opening the gated channel for substrate entry. Binds to the core proteasome via its C-terminus, which occupies the same binding sites as the proteasomal ATPases, opening the closed structure of the proteasome via an active gating mechanism. involved in DNA damage response: binds to acetylated histones and promotes degradation of histones (By similarity). Interacts with the 26S proteasomes. Upon MG132 treatment. The bromodomain-like (BRDL) region specifically recognizes and binds acetylated histones. No visible phenotype. Belongs to the BLM10 family.