Rocket Boys. Enjoy.
No, it’s not about the rock band. Nor is it about sleep physiology. Rather, this short blurb is intended to point out a recent review in Trends in Biochemical Sciences that ties together a long trickling of research extend back for many decades.
For at least 20 years, it has been known that a number of enzymes that catalyze reactons in intermediary metabolic pathways are also RNA binding proteins. The “classical” case is that of aconitase. This enzyme catalyzes the isomerization of citrate to isocitrate, a reaction that is part of the tricarboxylic acid cycle. The enzyme also binds the so-called iron-responsive element in mRNAs, and in so doing regulates RNA stability and translation. Aconitase activity and RNA binding are mutually exclusive, and the role the protein plays depends on teh iron status of the cell.
Similar RNA-binding moonlighting has since been shown for a number of other enzymes. I won’t list them here – the review does a nice job of this. The review also discusses the possible integration of metabolic cues with RNA homeostasis. It doesn’t touch on a more fascinating topic – the possibility that RNA binding may be a vestige of the deep past, reflecting the possibility that, at one time, all proteins may have interacted with RNA or been involved with RNA metabolism in some way. But the latter is a subject that better left for another review.