Phytochrome B photobodies are comprised of phytochrome B and its primary and secondary interacting proteins

ABSTRACT: Phytochrome B (phyB) is a plant photoreceptor that forms a membraneless organelle called a photobody. However, its constituents are not fully known. Here, we isolated phyB photobodies from Arabidopsis leaves using fluorescence-activated particle sorting and analyzed their components. We found that a photobody comprises ~1,500 phyB dimers along with other proteins that could be classified into two groups: The first includes proteins that directly interact with phyB and localize to the photobody when expressed in protoplasts, while the second includes proteins that interact with the first group proteins and require co-expression of a first-group protein to localize to the photobody. As an example of the second group, TOPLESS (TPL) interacts with PHOTOPERIODIC CONTROL OF HYPOCOTYL 1 (PCH1) and localizes to the photobody when co-expressed with PCH1. Mutations in TPL family members cause shortened hypocotyls under red light, demonstrating that the method identifies photobody components that regulate red light signaling. Together, our results support that phyB photobodies include not only phyB and its primary interacting proteins but also its secondary interacting proteins.

INSTRUMENT(S): Orbitrap Exploris 240

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

SUBMITTER: Ga Seul Lee  

LAB HEAD: Giltsu Choi

PROVIDER: PXD040702 | Pride | 2023-04-03

REPOSITORIES: Pride