The use of phospho-degrons for controlled protein expression in the cell cycle

Abstract

Cyclin-dependent kinases (Cdks) are the master regulators of the cell cycle, which together with their activating cyclin subunits, phosphorylate hundreds of targets to govern the cell cycle progression. The precise substrate targeting mechanisms of the Cdk complex have led to a hypothesis that the Cdk machinery could be used to control the expression and cellular concentration of any desired protein by fusion with different phospho-regulation modules. The modules consist of barcodes of linear motifs including phosphorylation sites and cyclins docking motifs. These barcodes are scanned by the Cdk complex and depending on the bar-code, the machinery will differentially regulate the protein in the cell cycle. This work shows that one such module, the Far1 degron, can be used to control the cellular concentration of different proteins. We also demonstrate that different versions of the degron allow us to fine-tune the cellular concentration of the targeted protein in different cell cycle phases.