the mper3 protein contains a pas domain, similar to mper1 and mper2. likely, mper3 binds to other proteins using this domain. however, while per1/2 have been shown to be important in the transcription-translation feedback loop involved in the intracellular circadian clock, the influence of per3 in this loop has not yet been fully elucidated, given that mper3 does not appear to be functionally redundant to mper1 and mper2. mper3 may not be a member of the core clock loop at all.