The novel co-activator CRABPII binds to RARα and RXRα via two nuclear receptor interacting domains and does not require the AF-2 'core'

We identify the RAR alpha, RXR alpha and CRABPII domains required for the physical interaction of these proteins. On RAR alpha and RXR alpha, the sequences correspond to the DEF and DE domains, respectively, but the interaction with CRABPII does not require the AF-2AD 'core'. On CRABPII, two interacting domains are identified (NRID1 and NRID2), one of which contains the only enhancement transactivation domain of CRABPII. The interaction is ligand-independent and does not require the ligand-binding domain of CRABPII. These results further stress that interaction of CRABPII with the nuclear receptors defines a novel level of transcriptional control. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.