The localization of phototropin to the plasma membrane defines a cold-sensing compartment in .

Plant cells perceive cold temperatures and initiate cellular responses to protect themselves against cold stress, but which cellular compartment mediates cold sensing has been unknown. Chloroplasts change their position in response to cold to optimize photosynthesis in plants in a process triggered by the blue-light photoreceptor phototropin (phot), which thus acts as a cold-sensing molecule. However, phot in plant cells is present in multiple cellular compartments, including the plasma membrane (PM), cytosol, Golgi apparatus, and chloroplast periphery, making it unclear where phot perceives cold and activates this cold-avoidance response.

The photo-thermochemical properties and functions of Marchantia phototropin encoded by an unduplicated gene in land plant evolution.

Phototropin (phot) is a blue light photoreceptor in plants and possesses two photosensory light‑oxygen-voltage (LOV1 and LOV2) domains with different photo-thermochemical properties. While liverworts contain a single copy of PHOT (e.g.