Prefoldins (PFDs) are proteins previously identified in different prokaryotes and eukaryotes organisms playing a key role in cytoskeleton function and maintenance. PFDs are organized as heterohexameric complexes that have the ability of binding and stabilizing nascent tubulin monomers in the cytoplasm where they promote microtubule polymerization.
Previous works carried out independently by Chris Somerville (US) and Julio Salinas, at Centro de Investigaciones Biológicas, identified several PFD family components in the model plant Arabidopsis thaliana. These works evidenced the evolutionary conservation of PFDs in plants and showed their implication in plant development.
Now, in a recent work published in Molecular Plant, the group of Dr. Julio Salinas describes the functional characterization of the Arabidopsis PFD complex in response to low temperature. They demonstrate that, in response to low temperature, the complex fine-tunes the levels of anthocyanins, essential pigments for plant adaptation to cold conditions, including freezing, by regulating the expression of genes involved in their biosynthesis. Most important, this study thoroughly describes how this function is achieved in the nucleus where the PFD complex accumulates to interact with HY5, a master regulator of anthocyanin biosynthesis, and to promote its ubiquitin-mediated degradation.
These results constitute the first evidence so far of the nuclear function of a PFD complex in plants to modulate gene expression and the accurate response of plants to adverse external stimuli.
Reference: Prefoldins Negatively Regulate Cold Acclimation in Arabidopsis thaliana by Promoting Nuclear Proteasome-Mediated HY5 Degradation. Perea-Resa et al. Molecular Plant (2017), http://dx.doi.org/10.1016/j.molp.2017.03.012