(E) Surface representation of the crystal structure (PDB: 5IGQ) of the COP1 WD40 domain colored according to electrostatic surface potential, calculated by APBS (Baker et al, 2001), in complex with the TRIB1 tail (cyan). Inset shows zoomed view of TRIB1 Q356 inserting its sidechain into the central channel of the COP1 WD40 domain. 