Figure 6

A proposed novel regulatory model for the Cul3 complex. A. A schematic diagram of the SCF complex demonstrates that the N-terminal domain of Cul1 is bound to Skp1 protein and a substrate adaptor F-box-containing protein. B. The current model of the BCR complex proposed that a BTB domain-containing protein utilizes other protein-protein interacting domains to bind its protein substrates. C. A proposed model for an alternative BCR ubiquitin ligase complex. In this case, we propose that the LRRs bind to Cul3 as well as to a unique region on the BTB domain-containing protein via a B/C-like box. This binding serves to change the binding position of the BTB domain-containing protein on Cul3 causing it to be a substrate instead of a substrate adaptor protein.