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Arabidopsis CHOLINE/ETHANOLAMINE KINASE 1 (CEK1) is a primary choline kinase localized at the endoplasmic reticulum (ER) and involved in ER stress tolerance
Author(s) -
Lin YingChen,
Kanehara Kazue,
Nakamura Yuki
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15915
Subject(s) - choline kinase , choline , endoplasmic reticulum , phosphatidylcholine , phosphocholine , biochemistry , pld2 , arabidopsis , microbiology and biotechnology , biology , kinase , unfolded protein response , phospholipid , chemistry , mutant , membrane , gene
Summary Choline kinase catalyzes the initial reaction step of choline metabolism that produces phosphocholine, a prerequisite for the biosynthesis of a primary phospholipid phosphatidylcholine. However, the primary choline kinase and its role in plant growth remained elusive in seed plants. Here, we showed that Arabidopsis CHOLINE/ETHANOLAMINE KINASE 1 (CEK1) encodes functional CEK that prefers choline than ethanolamine as a substrate in vitro and affects contents of choline and phosphocholine but not phosphatidylcholine in vivo . CEK1 is localized at endoplasmic reticulum (ER); upon tunicamycin‐induced ER stress, a null mutant of CEK1 showed hypersensitive phenotype in seedlings, albeit with no enhanced choline kinase activity. Our results demonstrate that CEK1 is a primary ER‐localized choline kinase in vivo that is required for ER stress tolerance possibly through the modulation of choline metabolites.