Structural Insights into the Assembly and Function of the SAGA Deubiquitinating Module

Abstract

Complex SAGA The SAGA (Spt-Ada-Gcn5-Acetyltransferase) complex, which is conserved in eukaryotes, plays a key role in regulating gene expression. It is comprised of 21 proteins, and its functions include histone acetylation and deubiquitination. Samara et al. (p. 1025 , published online 15 April) now report the structure of the SAGA deubiquitinating module (DUBm), a four-protein subcomplex, both on its own and bound to ubiquitin aldehyde. The domains are interconnected and stabilized by eight zinc atoms. The organization gives insight into why DUBm complex formation is required to activate the catalytic domain of the enzyme and suggests how DUBm might bind to monoubiquitinated histones.