Category Archives: Protein

Three stories about LIGHT

One

Carbon monoxide (CO): one of the nasty things in car emissions & cigarette smoke.  Also, a byproduct of the ever-important heme.  Heme, as you may recall, activates Rev-erb:

“Food for thought: an endogenous ligand of Rev-erb is heme (the iron-binding element in red blood cells).  Heme is degraded into bilirubin.  Elevated levels of bilirubin cause jaundice.  A treatment of neonatal jaundice is exposure to blue light.  Blue light is a major regulator of circadian rhythms and Rev-erb is an executive-level player in this game.  The primary mechanisms of blue light appear unrelated in these two models (melanopsin activation vs. bilirubin photoisomerization), but seem intertwined, because heme activates Rev-erb.  Cool.”

News: Disruption of the body’s internal clock causes disruption of metabolic processes

Science: Reciprocal regulation of carbon monoxide and the circadian clock (Klemz et al., 2016)

Tl;dr: heme degradation occurs on a circadian cycle and produces CO.  CO prevents Clock/Bmal1 from binding to DNA. Inhibiting this process throws off numerous other circadian rhythms in the liver.

SUNLIGHT and food in the morning, and let endogenously produced CO rhythmically tune the clock in the evening.

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