With Chlamydomonas reinhardtii as a model organism, the researchers found found that the level of RHYTHM OF CHLOROPLAST 15 (ROC15), a clock component in C. reinhardtii, decreased rapidly after blue, green, and red light light exposure in a circadian-phase–independent manner. Expression analyses and inhibitor experiments suggested that this process was regulated mainly by a proteasome-dependent protein degradation pathway.

Yoshimi NIWA et al., PNAS doi: 10.1073/pnas.1220004110 PNAS July 29, 2013