A non-catalytic function of Rev1 in translesion DNA synthesis and mutagenesis is mediated by its stable interaction with Rad5

► Rev1-Rad5 interaction via Rev1 C-terminal and the Rad5 N-terminal regions. ► Rev1-Rad5 interaction is required for translesion synthesis. ► A non-catalytic function of Rev1 is mediated via its interaction with Rad5. ► The C-terminal region of Rev1 is involved in its negative regulation.