RuvBL1 and RuvBL2 and Their Complex Proteins Implicated in Many Cellular Pathways

摘要

RuvBLl and its homolog RuvBL2 belong to the AAA~+ family of ATPases and play important roles in chromatin remodeling, in transcriptional regulation, in DNA repair and in the c-Myc and Wnt signaling pathways. Proteins involved in these pathways are often mutated in human cancers. Both RuvBL proteins form a complex and act alone or together in diverse cellular processes. The three-dimensional structures of human RuvBL1 refined using diffraction data to 2.2 A resolution and of the human RuvBL1/RuvBL2 complex with a truncated domain II at 3 A resolution are presented. The dodecameric RuvBL1/RuvBL2 complex structure differs from previously described models. It consists of two heterohexameric rings with alternating RuvBLl and RuvBL2 monomers that interact with each other via domain II. ATPase and helicase activities of RuvBL1 and RuvBL2 were also tested. Interestingly, truncation of domain II resulted not only in a substantial increase of ATP consumption by the RuvBL proteins, but also in stimulation of helicase activity, which was not observed with the full-length proteins.