The SAGA (Spt-Ada-Gcn5-acetyltransferase) complex performs multiple functions in transcription activation including deubiquitinating histone H2B, which is mediated by a subcomplex called the deubiquitinating module (DUBm). The yeast DUBm comprises a ...
The SAGA (Spt-Ada-Gcn5-acetyltransferase) complex performs multiple functions in transcription activation including deubiquitinating histone H2B, which is mediated by a subcomplex called the deubiquitinating module (DUBm). The yeast DUBm comprises a catalytic subunit, Ubp8, and three additional subunits, Sgf11, Sus1 and Sgf73, all of which are required for DUBm activity. A portion of the non-globular Sgf73 subunit lies between the Ubp8 catalytic domain and the zinc finger (ZnF)-UBP domain and has been proposed to contribute to deubiquitinating activity by maintaining the catalytic domain in an active conformation. Sgf73 contributes to maintaining both the organization and ubiquitin-binding conformation of Ubp8, thereby contributing to overall DUBm activity. This domain is a Sgf73 fragment in the DUB module. It is a zinc finger (ZnF) domain whose integrity is essential for the incorporation of this subunit into DUBm as well as for the catalytic activity of Ubp8, as either a short deletion or point mutations in Sgf73 zinc-coordinating residues disrupt the association of Sgf73 with the rest of the DUBm [1 -4].
