Analysis of Ubp8 purifications in the absence of SGF73. A. Mudpit analysis of various Ubp8Tap purifications reveals the effect of the loss of SGF73 and SPT20 versus SGF11 on Ubp8-associated complexes. In the absence of SGF73, Ubp8 only co-purifies with other deubiquitination module components, Sus1 and Sgf11. The numbers represent total peptides obtained for each component. B. Ubp8-associated complexes purified in the absence of SGF73 and SPT20 lose the ability to deubiquitinate histone H2B in vitro.