Fig. 10.

Regulation of the BAP1/ASXL2 complexes by DEUBAD ubiquitination. ASXL2 is constitutively monoubiquitinated by UBE2Es on its DEUBAD domain. Interaction of monoubiquitinated ASXL2 with BAP1 leads to its stabilization and the subsequent activation of the DUB complex. Otherwise monoubiquitinated ASXL2 is targeted by other E3 Ub-ligases for ubiquitin chain extension and proteasomal degradation. UBE2Es also target ASXL2 already in complex with BAP1, possibly dynamically regulating its activity. DUBs might also regulate the stability of both free and complexed ASXL2. Mutation of ASXL2 lysine 370 or cancer mutations that abolish ASXL2-BAP1 interaction lead to defective monoubiquitination and subsequent loss of BAP1 DUB activity and tumor suppression