FIGURE 7.

Model for regulation of SCF^Fbxl3 complex formation. Fbxl3 essentially does not form an SCF complex in the absence of its association with Cry1 (left), given that it appears to associate with an as yet unknown protein (X) that interferes with its interaction with Skp1-Cul1 in mammalian cells. As Cry1 accumulates, a subset of Cry1 dissociates from Per and FAD (center), and the binding of the free form of Cry1 to the LRR domain of Fbxl3 induces the dissociation of this unknown protein and thereby promotes formation of the SCF^Fbxl3 complex (right). N, Nedd8; F, FAD; Ub, ubiquitin. See “Discussion” for further details.