Prolyl isomerase Pin1 acts as a switch to control the degree of substrate ubiquitylation

Pin1 regulates protein degradation and is now shown to control the ubiquitylation status of its targets. In yeast, Pin1 decreases the ubiquitylation of the transcription factor Spt23 to activate it, while low Pin1 levels increase its degradation. Similarly, inhibition of Pin1 in mammalian cells increases p53 ubiquitylation and nuclear degradation.