title: The Arabidopsis inositol 1,3,4-trisphosphate 5/6 kinase, AtItpk-1, is involved in plant photomorphogenesis under red light conditions, possibly via interaction with COP9 signalosome.
abstract: The COP9 signalosome (CSN) plays important roles in multifaceted cellular processes. Study has shown that inositol 1,3,4-trisphosphate 5/6 kinase (5/6 kinase) interacts with CSN in mammalian cells. However, the biological function of the interaction still remains unknown. Here, we report that the Arabidopsis inositol 1,3,4-trisphosphate 5/6 kinase (AtItpk-1) is also associated with CSN and involved in photomorphogenesis under red light (RL) conditions, as demonstrated by co-immunoprecipitation of AtItpk-1 with CSN and characterization of the atitpk-1 mutants. Expression analysis showed that AtItpk-1 had the same sub-cellular localization and organ expression pattern as CSN. Furthermore, autophosphorylation analysis showed that AtItpk-1 has protein kinase activity. Under RL, the atitpk-1 mutants exhibited phenotype slightly similar with that of the csn mutants, indicating that 5/6 kinase might be involved in the same developmental pathway as CSN. This study suggests that AtItpk-1 may function as a protein kinase that is involved in photomorphogenesis possibly via interaction with COP9 signalosome under red light.
authors.affiliation: National Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, China.
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Qin
authors.forename: Qi-Jun
authors.initials: QJ
authors.lastname: Chen
authors.forename: Zhe
authors.initials: Z
authors.lastname: Tong
authors.forename: Xue-Chen
authors.initials: XC
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000201:enzymology*; D000075686:COP9 Signalosome Complex; D004269:DNA, Bacterial / Q000378:metabolism; D047468:Immunoprecipitation; D008027:Light; D009024:Morphogenesis; D046912:Multiprotein Complexes / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D004269:DNA, Bacterial; D046912:Multiprotein Complexes; C036483:T-DNA; D017853:Phosphotransferases (Alcohol Group Acceptor); C056875:myo-inositol-trisphosphate 6-kinase; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex