Number of the records: 1

Arabidopsis ROCK1 transports UDP-GlcNAc/UDP-GalNAc and regulates ER protein quality control and cytokinin activity

SYSNO ASEP	0444417
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Arabidopsis ROCK1 transports UDP-GlcNAc/UDP-GalNAc and regulates ER protein quality control and cytokinin activity
Author(s)	Niemann, M.C.E. (DE) Bartrina, I. (DE) Ashikov, A. (DE) Weber, H. (DE) Novák, Ondřej (UEB-Q)_{RID, ORCID, SAI} Spíchal, Lukáš (UEB-Q)_{RID, ORCID} Strnad, Miroslav (UEB-Q)_{RID, ORCID} Strasser, R. (AT) Bakker, H. (DE) Schmülling, T. (DE) Werner, T. (DE)
Source Title	Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences - ISSN 0027-8424 Roč. 112, č. 1 (2015), s. 291-296
Number of pages	6 s.
Language	eng - English
Country	US - United States
Keywords	ROCK1 ; cytokinin ; CKX
Subject RIV	EF - Botanics
R&D Projects	LK21306 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
	LO1204 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
Institutional support	UEB-Q - RVO:61389030
UT WOS	000347447100068
DOI	10.1073/pnas.1419050112
Annotation	The formation of glycoconjugates depends on nucleotide sugars, which serve as donor substrates for glycosyltransferases in the lumen of Golgi vesicles and the endoplasmic reticulum (ER). Import of nucleotide sugars from the cytosol is an important prerequisite for these reactions and is mediated by nucleotide sugar transporters. Here, we report the identification of REPRESSOR OF CYTOKININ DEFICIENCY 1 (ROCK1, At5g65000) as an ER-localized facilitator of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylgalactosamine (UDP-GalNAc) transport in Arabidopsis thaliana. Mutant alleles of ROCK1 suppress phenotypes inferred by a reduced concentration of the plant hormone cytokinin. This suppression is caused by the loss of activity of cytokinin-degrading enzymes, cytokinin oxidases/dehydrogenases (CKXs). Cytokinin plays an essential role in regulating shoot apical meristem (SAM) activity and shoot architecture. We show that rock1 enhances SAM activity and organ formation rate, demonstrating an important role of ROCK1 in regulating the cytokinin signal in the meristematic cells through modulating activity of CKX proteins. Intriguingly, genetic and molecular analysis indicated that N-glycosylation of CKX1 was not affected by the lack of ROCK1-mediated supply of UDPGlcNAc. In contrast, we show that CKX1 stability is regulated in a proteasome-dependent manner and that ROCK1 regulates the CKX1 level. The increased unfolded protein response in rock1 plants and suppression of phenotypes caused by the defective brassinosteroid receptor bri1-9 strongly suggest that the ROCK1 activity is an important part of the ER quality control system, which determines the fate of aberrant proteins in the secretory pathway.
Workplace	Institute of Experimental Botany
Contact	David Klier, knihovna@ueb.cas.cz, Tel.: 220 390 469
Year of Publishing	2016

Number of the records: 1