Universität zu Köln

Schenk, Tobias, Trimborn, Laura ORCID: 0000-0002-0475-4585, Chen, Song ORCID: 0000-0003-0726-7114, Schenkel, Christian and Hoecker, Ute ORCID: 0000-0002-5636-9777 (2021). Light-induced degradation of SPA2 via its N-terminal kinase domain is required for photomorphogenesis. Plant Physiol., 187 (1). S. 276 - 289. CARY: OXFORD UNIV PRESS INC. ISSN 1532-2548

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Abstract

Arabidopsis (Arabidopsis thaliana) CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) and members of the SUPPRESSOR OF PHYTOCHROMEA-105 (SPA) protein family form an E3 ubiquitin ligase that suppresses light signaling in darkness by polyubiquitinating positive regulators of the light response. COP1/SPA is inactivated by light to allow photomorphogenesis to proceed. Mechanisms of inactivation include light-induced degradation of SPA1 and, in particular, SPA2, corresponding to a particularly efficient inactivation of COP1/SPA2 by light. Here, we show that SPA3 and SPA4 proteins are stable in the light, indicating that light-induced destabilization is specific to SPA1 and SPA2, possibly related to the predominant function of SPA1 and SPA2 in dark-grown etiolating seedlings. SPA2 degradation involves cullin and the COP10-DEETIOLATED-DAMAGED-DNA BINDING PROTEIN (DDB1) CDD complex, besides COP1. Consistent with this finding, light-induced SPA2 degradation required the DDB1-interacting Trp-Asp (WD)-repeat domain of SPA2. Deletion of the N-terminus of SPA2 containing the kinase domain led to strong stabilization of SPA2 in darkness and fully abolished light-induced degradation of SPA2. This prevented seedling de-etiolation even in very strong far-red and blue light and reduced de-etiolation in red light, indicating destabilization of SPA2 through its N-terminal domain is essential for light response. SPA2 is exclusively destabilized by phytochrome A in far-red and blue light. However, deletion of the N-terminal domain of SPA2 did not abolish SPA2-phytochrome A interaction in yeast nor in vivo. Our domain mapping suggests there are two SPA2-phytochrome A interacting domains, the N-terminal domain and the WD-repeat domain. Conferring a light-induced SPA2-phyA interaction only via the WD-repeat domain may thus not lead to COP1/SPA2 inactivation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schenk, Tobias UNSPECIFIED UNSPECIFIED UNSPECIFIED Trimborn, Laura UNSPECIFIED orcid.org/0000-0002-0475-4585 UNSPECIFIED Chen, Song UNSPECIFIED orcid.org/0000-0003-0726-7114 UNSPECIFIED Schenkel, Christian UNSPECIFIED UNSPECIFIED UNSPECIFIED Hoecker, Ute UNSPECIFIED orcid.org/0000-0002-5636-9777 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-568794
DOI:	10.1093/plphys/kiab156
Journal or Publication Title:	Plant Physiol.
Volume:	187
Number:	1
Page Range:	S. 276 - 289
Date:	2021
Publisher:	OXFORD UNIV PRESS INC
Place of Publication:	CARY
ISSN:	1532-2548
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language UBIQUITIN LIGASE COP1/SPA; DEPENDENT INTERACTION; NUCLEAR ACCUMULATION; MEDIATED REGULATION; CRYPTOCHROME 1; ARABIDOPSIS; PROTEINS; PHYTOCHROME; PLANT; GENE Multiple languages Plant Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/56879