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.
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.
Qin
Zhi-Xiang
ZX
National Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, China.
Chen
Qi-Jun
QJ
Tong
Zhe
Z
Wang
Xue-Chen
XC
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
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