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The cytokinin oxidase/dehydrogenase CKX1 is a membrane-bound protein requiring homooligomerization in the endoplasmic reticulum for its cellular activity
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SYSNO ASEP 0488778 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title The cytokinin oxidase/dehydrogenase CKX1 is a membrane-bound protein requiring homooligomerization in the endoplasmic reticulum for its cellular activity Author(s) Niemann, M.C.E. (DE)
Weber, H. (DE)
Hluska, T. (CZ)
Leonte, G. (DE)
Anderson, S. P. (US)
Novák, Ondřej (UEB-Q) RID, ORCID, SAI
Senes, A. (US)
Werner, Tomáš (UEB-Q)Number of authors 8 Source Title Plant Physiology. - : Oxford University Press - ISSN 0032-0889
Roč. 176, č. 3 (2018), s. 2024-2039Number of pages 16 s. Language eng - English Country US - United States Keywords HELIX-HELIX ASSOCIATION ; VIRUS MOVEMENT PROTEIN ; RECEPTOR-LIKE PROTEINS Subject RIV EB - Genetics ; Molecular Biology OECD category Cell biology R&D Projects LO1204 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) GA15-22322S GA ČR - Czech Science Foundation (CSF) Institutional support UEB-Q - RVO:61389030 UT WOS 000426848300017 EID SCOPUS 85042554344 DOI 10.1104/pp.17.00925 Annotation Degradation of the plant hormone cytokinin is controlled by cytokinin oxidase/dehydrogenase (CKX) enzymes. The molecular and cellular behavior of these proteins is still largely unknown. In this study, we show that CKX1 is a type II single-pass membrane protein that localizes predominantly to the endoplasmic reticulum (ER) in Arabidopsis (Arabidopsis thaliana). This indicates that this CKX isoform is a bona fide ER protein directly controlling the cytokinin, which triggers the signaling from the ER. By using various approaches, we demonstrate that CKX1 forms homodimers and homooligomers in vivo. The amino-terminal part of CKX1 was necessary and sufficient for the protein oligomerization as well as for targeting and retention in the ER. Moreover, we show that protein-protein interaction is largely facilitated by transmembrane helices and depends on a functional GxxxG-like interaction motif. Importantly, mutations rendering CKX1 monomeric interfere with its steady-state localization in the ER and cause a loss of the CKX1 biological activity by increasing its ER-associated degradation. Therefore, our study provides evidence that oligomerization is a crucial parameter regulating CKX1 biological activity and the cytokinin concentration in the ER. The work also lends strong support for the cytokinin signaling from the ER and for the functional relevance of the cytokinin pool in this compartment. Workplace Institute of Experimental Botany Contact David Klier, knihovna@ueb.cas.cz, Tel.: 220 390 469 Year of Publishing 2019
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