<;P>;PROBLEM TO BE SOLVED: To provide a new ubiquitin ligase and its adapter components. <;P>;SOLUTION: There are disclosed: a ubiquitin ligase component comprising BAZF; a ubiquitin ligase component comprising BAZF and CUL3; a ubiquitin ligase including the components; a ubiquitin ligase controlling agent featured by including a substance for controlling the expression of BAZF; a Notch signal controlling agent featured by including any of these components, ubiquitin ligase and its controlling agents; or preventive or therapeutic agents for diseases caused by the abnormality of Notch signaling system. <;P>;COPYRIGHT: (C)2011,JPO&INPIT