The intrinsically disordered region from PP2C phosphatases functions as a conserved CO2 sensor

Nat Cell Biol. 2022 Jul;24(7):1029-1037. doi: 10.1038/s41556-022-00936-6. Epub 2022 Jun 16.

Abstract

Carbon dioxide not only plays a central role in the carbon cycle, but also acts as a crucial signal in living cells. Adaptation to changing CO2 concentrations is critical for all organisms. Conversion of CO2 to HCO3- by carbonic anhydrase and subsequent HCO3--triggered signalling are thought to be important for cellular responses to CO2 (refs. 1-3). However, carbonic anhydrases are suggested to transduce a change in CO2 rather than be a direct CO2 sensor4,5, the mechanism(s) by which organisms sense CO2 remain unknown. Here we demonstrate that a unique group of PP2C phosphatases from fungi and plants senses CO2, but not HCO3-, to control diverse cellular programmes. Different from other phosphatases, these PP2Cs all have an intrinsically disordered region (IDR). They formed reversible liquid-like droplets through phase separation both in cells and in vitro, and were activated in response to elevated environmental CO2 in an IDR-dependent manner. The IDRs in PP2Cs are characterized by a sequence of polar amino acids enriched in serine/threonine, which provides CO2 responsiveness. CO2-responsive activation of PP2Cs via the serine/threonine-rich IDR-mediated phase separation represents a direct CO2 sensing mechanism and is widely exploited.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Carbon Dioxide* / metabolism
  • Carbonic Anhydrases* / metabolism
  • Phosphoric Monoester Hydrolases
  • Serine
  • Threonine

Substances

  • Carbon Dioxide
  • Threonine
  • Serine
  • Phosphoric Monoester Hydrolases
  • Carbonic Anhydrases