Plants feel the heat: How a protein 'thermometer' helps plants adapt to climate

Sadie Harley

Scientific Editor

Robert Egan

Senior Editor

Plants continuously adapt to environmental changes, and temperature is a key signal for growth and flowering. How plant thermometers, or "thermosensors," work at the molecular level is not well understood.

An international team led by Professor Dr. Philip Wigge of the Leibniz Institute for Horticultural Sciences (IGZ), in collaboration with the Max Planck Institute of Molecular Plant Physiology and the Karolinska Institute (Sweden), investigated how the molecular regulator COP1 responds to temperature. At higher temperatures, COP1 changes structure, switching on and activating plant growth.

The paper is published in the journal Cell.

A protein with a built-in temperature switch

COP1 (CONSTITUTIVE PHOTOMORPHOGENESIS 1) is a key regulator in plant signaling. It is involved in regulating growth and development by integrating light and temperature signals. COP1 binds to and triggers the degradation of other proteins.

Using molecular and biophysical methods, the research team now demonstrates in the model plant Arabidopsis thaliana (thale cress) that COP1 regulates its activity through a temperature-responsive mechanism built into the protein itself. The protein adopts two different conformational shapes.

At lower temperatures, it predominantly exists in a closed, less active form. A short region at one end of the COP1 protein contains two consecutive amino acids—valine and proline, abbreviated as VP. This region can bind to a site on COP1, called the WD40 domain, where target proteins would normally attach.

At lower temperatures, this internal interaction keeps COP1 in a closed, less active conformation and acts as a built-in latch. Other proteins, including the growth regulator HY5, have less access to the binding site.

As the temperature rises, the internal interaction increasingly loosens and COP1 adopts a more open shape. The binding site becomes more accessible, allowing COP1 to bind other proteins and mark them for degradation. Consequently, the abundance of target proteins such as HY5 decreases and plant growth is no longer inhibited. The structural change in COP1 therefore influences which signals are transmitted within the plant.

Differences between plant species offer clues to adaptation

The researchers specifically modified the VP motif and its binding affinity to the WD40 domain. This allowed them to influence the temperature at which COP1 becomes active, as well as the extent to which the plants respond to temperature differences. Natural variations in the amino acid sequence of COP1 were also found to be associated with altered temperature responses.

Furthermore, the team compared protein sequences from different plant species. Interestingly, plants from cooler climates have a more flexible COP1, which responds more readily to temperature, compared to plants from hotter climates. By changing the flexibility of COP1, the team was able to alter how much plants respond to temperature. This knowledge could be useful for adapting crops to hotter climates.

Dr. Philip A. Wigge (IGZ), leading scientist of the study, says, "Temperature is molecular motion, but it has been something of a mystery how the proteins in the cell can sense and transmit this information. Climate change is having a growing effect on plants around the world and is already impacting crop yields. It is more important than ever that we understand how thermometers in the cell work."

Dr. Laura Orellana (Karolinska Institutet), senior co-author and expert in computational biology and protein biophysics, adds, "I usually study how mutations affect protein motions and function in cancer, so I was excited to join this collaboration. Using molecular dynamics simulations on supercomputers, we could 'see' how a flexible part of COP1 moves away as temperature rises, allowing it to bind other proteins and target them for degradation.

"It is fascinating that the same physical principles governing protein function in our cells can explain how plants sense temperature, showing how research in one field can unexpectedly illuminate another."

Dr. Arun Sampathkumar (MPI-MP), co-author and expert in cell biology, states, "The cell is a fascinating machine, and with advanced microscopy techniques we could directly observe how the COP1 protein can change its shape in response to warm temperature, truly a molecular switch!"

The findings provide new insights into how plants process temperature information. The mechanism investigated could serve as a starting point for specifically modifying temperature responses in crop plants. However, it remains to be investigated whether and how this can be applied.

Publication details

Wei Zeng et al., COP1 is a temperature-responsive switch in Arabidopsis, Cell (2026). DOI: 10.1016/j.cell.2026.10.036

Journal information:
Cell

Citation: Plants feel the heat: How a protein 'thermometer' helps plants adapt to climate (2026, November 11) retrieved 11 November 2026 from https://phys.org/news/2026-11-protein-thermometer-climate.html