title: Compilation and characterization of a novel WNK family of protein kinases in Arabiodpsis thaliana with reference to circadian rhythms.
abstract: The complete genome sequence of Arabidopsis thaliana revealed that this higher plant has a tremendous number of protein kinases. We recently isolated a novel type of protein kinase, named AtWNK1, which shows an in vitro ability to phosphorylate the APRR3 member of the APRR1/TOC1 quintet that has been implicated in a mechanism underlying circadian rhythms in Arabidopsis. We here address two issues, one general and one specific, as to this novel protein kinase. We first asked the general question of how many WNK family members are present in this higher plant, then whether or not other members are also relevant to circadian rhythms. The results of our analyses showed that Arabidopsis has at least 9 members of the WNK1 family of protein kinases (designated here as WNK1 to WNK9), the structural design of which is clearly distinct from those of other known protein kinases, such as receptor-like kinases and mitogen-activated protein kinases. They were examined with special reference to the circadian-related APRR1/TOC1 quintet. It was found that not only the transcription of the WNK1 gene, but also those of three other members (WNK2, WNK4, and WNK6) are under the control of circadian rhythms. These results suggested that certain members of the WNK family of protein kinases might play roles in a mechanism that generates circadian rhythms in Arabidopsis.
authors.affiliation: Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Norihito
authors.initials: N
authors.lastname: Nakamichi
authors.forename: Masaya
authors.initials: M
authors.lastname: Murakami-Kojima
authors.forename: Eriko
authors.initials: E
authors.lastname: Sato
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Kishi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yamashino
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mizuno
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern / Q000379:methods; D002940:Circadian Rhythm / Q000502:physiology*; D018744:DNA, Plant / Q000235:genetics / Q000302:isolation & purification; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010802:Phylogeny; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D000076204:WNK Lysine-Deficient Protein Kinase 1
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D017346:Protein Serine-Threonine Kinases; D000076204:WNK Lysine-Deficient Protein Kinase 1; C465128:WNK1 protein, Arabidopsis