Abstract
The core clock protein PERIOD (PER) plays an important role in the regulation of the circadian clock. The rate at which PER degrades is a key factor determining the behavioral period. Here we use the Drosophila model to investigate mechanisms that influence the stability of PER. We studied two distinct mechanisms of controlling the rate of PER degradation. We discovered that the cAMP up-regulatory effects of PDF result in a decrease of PER degradation. This phenomenon appears to require the activation of PKA. Additionally, we discover a new mechanism in which PER degradation accelerates after interacting with CLOCK(CLK) in vitro, suggesting that this CLK-PER interaction is important to PER stability. In summary, we shed light on the mechanisms of how PDF affects PER stability and investigate a potentially undiscovered relationship between CLK and PER degradation.