The Arabidopsis PHYTOCHROME KINASE SUBSTRATE2 protein is a phototropin signaling element that regulates leaf flattening and leaf positioning

de Carbonnel, Matthieu; Davis, Phillip; Roelfsema, M Rob G; Inoue, Shin-Ichiro; Schepens, Isabelle; Lariguet, Patricia; Geisler, Markus; Shimazaki, Ken-Ichiro; Hangarter, Roger; Fankhauser, Christian (2010). The Arabidopsis PHYTOCHROME KINASE SUBSTRATE2 protein is a phototropin signaling element that regulates leaf flattening and leaf positioning. Plant Physiology, 152(3), pp. 1391-405. Rockville, Md.: American Society of Plant Physiologists 10.1104/pp.109.150441

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In Arabidopsis (Arabidopsis thaliana), the blue light photoreceptor phototropins (phot1 and phot2) fine-tune the photosynthetic status of the plant by controlling several important adaptive processes in response to environmental light variations. These processes include stem and petiole phototropism (leaf positioning), leaf flattening, stomatal opening, and chloroplast movements. The PHYTOCHROME KINASE SUBSTRATE (PKS) protein family comprises four members in Arabidopsis (PKS1-PKS4). PKS1 is a novel phot1 signaling element during phototropism, as it interacts with phot1 and the important signaling element NONPHOTOTROPIC HYPOCOTYL3 (NPH3) and is required for normal phot1-mediated phototropism. In this study, we have analyzed more globally the role of three PKS members (PKS1, PKS2, and PKS4). Systematic analysis of mutants reveals that PKS2 (and to a lesser extent PKS1) act in the same subset of phototropin-controlled responses as NPH3, namely leaf flattening and positioning. PKS1, PKS2, and NPH3 coimmunoprecipitate with both phot1-green fluorescent protein and phot2-green fluorescent protein in leaf extracts. Genetic experiments position PKS2 within phot1 and phot2 pathways controlling leaf positioning and leaf flattening, respectively. NPH3 can act in both phot1 and phot2 pathways, and synergistic interactions observed between pks2 and nph3 mutants suggest complementary roles of PKS2 and NPH3 during phototropin signaling. Finally, several observations further suggest that PKS2 may regulate leaf flattening and positioning by controlling auxin homeostasis. Together with previous findings, our results indicate that the PKS proteins represent an important family of phototropin signaling proteins.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Department of Dermatology, Urology, Rheumatology, Nephrology, Osteoporosis (DURN) > Clinic of Dermatology
UniBE Contributor:	Schepens, Isabelle
ISSN:	0032-0889
Publisher:	American Society of Plant Physiologists
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:12
Last Modified:	05 Dec 2022 14:01
Publisher DOI:	10.1104/pp.109.150441
PubMed ID:	20071603
Web of Science ID:	000276329500023
URI:	https://boris.unibe.ch/id/eprint/2271 (FactScience: 204662)