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008			250311b |||||||| |||| 00| 0 eng d
022			_a0176-1617
040			_aMSU _bEnglish _cMSU _erda
050	0	0	_aQK711.2 JOU
100	1		_aDimkovikj, Aleksandar _eauthor
245	1	0	_aStuck between a ROS and a hard place: Analysis of the ubiquitin proteasome pathway in selenocysteine treated Brassica napus reveals different toxicities during selenium assimilation _ccreated by Aleksandar Dimkovikj, Brian Fisher, Kim Hutchison, Doug Van Hoewyk
264	1		_aAmsterdam: _bElsevier GmbH, _c2015.
336			_2rdacontent _atext _btxt
337			_2rdamedia _aunmediated _bn
338			_2rdacarrier _avolume _bnc
440			_aJournal of plant physiology _vVolume 181
520	3		_aDuring the selenium assimilation pathway, inorganic selenate and selenite are reduced to form selenocysteine (Sec). Tolerance to selenium in plants has long been attributable to minimizing the replacement of cysteine with selenocysteine, which can result in nonspecific selenoproteins that are potentially misfolded. Despite this widely accepted assumption, there is no evidence in higher plants demonstrating that selenocysteine induces toxicity by resulting in malformed proteins. In this study, we use Brassica napus to analyze the ubiquitin-proteasome pathway, which is capable of removing misfolded proteins. Sec rapidly increased proteasome activity and levels of ubiquitinated proteins, strongly indicating that selenocysteine induces protein misfolding. Proteasome inhibition increased the amount of selenium in protein in Sec-treated plants. Collectively, these data provide a mechanism that accounts for Sec toxicity. Additionally, Sec did not cause oxidative stress as judged by examining levels of superoxide using fluorescent microscopy. Therefore, the cellular response to Sec is different compared to selenite, which was recently shown to increase antioxidant metabolism in response to elevated mitochondrial superoxide that ultimately impaired proteasome activity. Therefore, plants must contend with two divergent modes of cytotoxicity during selenium assimilation. Selenite can result in oxidative stress, but increased flux of selenite reduction can yield Sec that in turn can cause protein misfolding.
650			_aProteasome
650			_aReactive oxygen species
650			_aSelenium
700	1		_aFisher, Brian _eco-author
700	1		_aHutchison, Kim _eco-author
700	1		_aVan Hoewyk, Doug _eco-author
856			_uhttps://doi.org/10.1016/j.jplph.2015.04.003
942			_2lcc _cJA
999			_c169226 _d169226