Phytochrome B photobody components

Abstract

SummaryPhytochrome B (phyB) is a red and far‐red photoreceptor that promotes light responses. Upon photoactivation, phyB enters the nucleus and forms a molecular condensate called a photobody through liquid–liquid phase separation. Phytochrome B photobody comprises phyB, the main scaffold molecule, and at least 37 client proteins. These clients belong to diverse functional categories enriched with transcription regulators, encompassing both positive and negative light signaling factors, with the functional bias toward the negative factors. The functionally diverse clients suggest that phyB photobody acts either as a trap to capture proteins, including negatively acting transcription regulators, for processes such as sequestration, modification, or degradation or as a hub where proteins are brought into close proximity for interaction in a light‐dependent manner.

PIF transcription factors-versatile plant epigenome landscapers

“…After photoactivation, phyB translocates from the cytosol to the nucleus where it compartmentalizes into PBs through liquid-liquid phase separation (LLPS) (Sakamoto and Nagatani, 1996;Kircher et al, 1999;Chen et al, 2003;Chen et al, 2022). PBs function as regulatory light and temperature modules, housing a variety of signaling components that interact directly or indirectly with phyB (Van Buskirk et al, 2012;Jung et al, 2016;Legris et al, 2016;Hahm et al, 2020;Pardi and Nusinow, 2021;Kim et al, 2023;Kwon et al, 2024;Willige et al, 2024). One of the most critical PB component are the PIFs, a family of basic helix-loop-helix (bHLH) TFs which acts a transcriptional activators or repressors (Ni et al, 1998;Huq and Quail, 2002;Huq et al, 2004;Oh et al, 2004;Castillon et al, 2007;Leivar et al, 2008;Shen et al, 2008;Leivar and Quail, 2011;Leivar and Monte, 2014).…”