Universität zu Köln

Balcerowicz, Martin ORCID: 0000-0001-9462-4436, Kerner, Konstantin, Schenkel, Christian and Hoecker, Ute ORCID: 0000-0002-5636-9777 (2017). SPA Proteins Affect the Subcellular Localization of COP1 in the COP1/SPA Ubiquitin Ligase Complex during Photomorphogenesis. Plant Physiol., 174 (3). S. 1314 - 1322. ROCKVILLE: AMER SOC PLANT BIOLOGISTS. ISSN 1532-2548

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Abstract

The Arabidopsis (Arabidopsis thaliana) COP1/SPA ubiquitin ligase is a central repressor that suppresses light signaling in darkness by targeting positive regulators of the light response, mainly transcription factors, for degradation. Light inactivates COP1/SPA, in part by excluding COP1 from the nucleus. SPA proteins are essential cofactors of COP1, but their exact role in the COP1/SPA complex is thus far unknown. To unravel a potential role of SPA proteins in COP1 nucleocytoplasmic partitioning, we monitored the subcellular localization of COP1 in a spa1234 quadruple mutant (spaQn). We analyzed a YFP-COP1-expressing transgenic line and endogenous COP1 after subcellular fractionation. In dark-grown seedlings, both YFP-COP1 and endogenous COP1 accumulated in the nucleus in the absence and presence of SPA proteins, indicating that SPA proteins are not required for nuclear localization of COP1 in darkness. In contrast, in white light-grown seedlings, spaQn mutants failed to relocalize COP1 from the nucleus to the cytoplasm. Hence, SPA proteins are necessary for the light-controlled change in COP1 subcellular localization. We conclude that SPA proteins have a dual role: (1) they are required for light-responsiveness of COP1 subcellular localization, and (2) they promote COP1 activity in darkness in a fashion that is independent of the nuclear import/nuclear retention of COP1.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Balcerowicz, Martin UNSPECIFIED orcid.org/0000-0001-9462-4436 UNSPECIFIED Kerner, Konstantin UNSPECIFIED UNSPECIFIED UNSPECIFIED Schenkel, Christian UNSPECIFIED UNSPECIFIED UNSPECIFIED Hoecker, Ute UNSPECIFIED orcid.org/0000-0002-5636-9777 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-226237
DOI:	10.1104/pp.17.00488
Journal or Publication Title:	Plant Physiol.
Volume:	174
Number:	3
Page Range:	S. 1314 - 1322
Date:	2017
Publisher:	AMER SOC PLANT BIOLOGISTS
Place of Publication:	ROCKVILLE
ISSN:	1532-2548
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Biology > Botanical Institute
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language LIGHT-DEPENDENT INTERACTION; PHYTOCHROME-A PHOTORECEPTOR; FAR-RED LIGHT; ARABIDOPSIS COP1; BLUE-LIGHT; NUCLEAR ACCUMULATION; GENE-EXPRESSION; IMAGE-ANALYSIS; CONSTITUTIVELY PHOTOMORPHOGENIC1; REPRESS PHOTOMORPHOGENESIS Multiple languages Plant Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/22623