@article {18725, title = {Ubistatins Inhibit Proteasome-Dependent Degradation by Binding the Ubiquitin Chain}, journal = {Science}, volume = {306}, year = {2004}, month = {2004/10/01/}, pages = {117 - 120}, abstract = {To identify previously unknown small molecules that inhibit cell cycle machinery, we performed a chemical genetic screen in Xenopus extracts. One class of inhibitors, termed ubistatins, blocked cell cycle progression by inhibiting cyclin B proteolysis and inhibited degradation of ubiquitinated Sic1 by purified proteasomes. Ubistatins blocked the binding of ubiquitinated substrates to the proteasome by targeting the ubiquitin-ubiquitin interface of Lys48-linked chains. The same interface is recognized by ubiquitin-chain receptors of the proteasome, indicating that ubistatins act by disrupting a critical protein-protein interaction in the ubiquitin-proteasome system.}, doi = {10.1126/science.1100946}, url = {http://www.sciencemag.org/cgi/content/abstract/sci;306/5693/117}, author = {Verma,Rati and Peters,Noel R. and D{\textquoteright}Onofrio,Mariapina and Tochtrop,Gregory P. and Sakamoto,Kathleen M. and Varadan,Ranjani and Zhang,Mingsheng and Coffino,Philip and Fushman, David and Deshaies,Raymond J. and King,Randall W.} }