Dss1 Is a 26S Proteasome Ubiquitin Receptor

作者：Paraskevopoulos Konstantinos; Kriegenburg Franziska; Tatham Michael H; Roesner Heike I; Medina Bethan; Larsen Ida B; Brandstrup Rikke; Hardwick Kevin G; Hay Ronald T; Kragelund Birthe B; Hartmann Petersen Rasmus^*; Gordon Colin

来源：Molecular Cell, 2014, 56(3): 453-461.

DOI：10.1016/j.molcel.2014.09.008

The ubiquitin-proteasome system is the major pathway for protein degradation in eukaryotic cells. Proteins to be degraded are conjugated to ubiquitin chains that act as recognition signals for the 26S proteasome. The proteasome subunits Rpn10 and Rpn13 are known to bind ubiquitin, but genetic and biochemical data suggest the existence of at least one other substrate receptor. Here, we show that the phylogenetically conserved proteasome subunit Dss1 (Sem1) binds ubiquitin chains linked by K63 and K48. Atomic resolution data show that Dss1 is disordered and binds ubiquitin by binding sites characterized by acidic and hydrophobic residues. The complementary binding region in ubiquitin is composed of a hydrophobic patch formed by I13, I44, and L69 flanked by two basic regions. Mutations in the ubiquitin-binding site of Dss1 cause growth defects and accumulation of ubiquitylated proteins.

• 出版日期2014-11-6