Component of the transcription regulatory histone acetylation (HAT) complex SAGA, a multiprotein complex that activates transcription by remodeling chromatin and mediating histone acetylation and deubiquitination. Within the SAGA complex, participates in a subcomplex that specifically deubiquitinates histone H2B. The SAGA complex is recruited to specific gene promoters by activators, where it is required for transcription. Required for nuclear receptor-mediated transactivation. Binds independently on SAGA to promoters in an RNA-dependent manner. Binds to mRNA and is essential for total mRNA export from the nucleus. Required to counteract heterochromatin silencing. Controls the development of neuronal connectivity in visual system by being required for accurate axon targeting in the optic lobe. Required for expression of ecdysone-induced genes such as br/broad. Component of some SAGA transcription coactivator-HAT complexes, at least composed of Ada2b, not/nonstop, Pcaf/Gcn5, Sgf11 and Spt3. Within the SAGA complex, Sgf11, e(y)2, and not/nonstop form an additional subcomplex of SAGA called the DUB module (deubiquitination module). Interacts directly with not/nonstop. Interacts with the AMEX complex component xmas-2. Interacts with Cbp80; important for promoter recruitment of Sgf11 that is not associated with the DUB module. Localizes to nuclear periphery, in contact with the nuclear pore complex (NPC). The long N-terminal helix forms part of the 'assembly lobe' of the SAGA deubiquitination module. The C-terminal SGF11-type zinc-finger domain together with the C-terminal catalytic domain of not/nonstop forms the 'catalytic lobe' of the SAGA deubiquitination module. Belongs to the SGF11 family.