title: Calcineurin B-like protein CBL10 directly interacts with AKT1 and modulates K+ homeostasis in Arabidopsis.
abstract: Potassium transporters and channels play crucial roles in K+ uptake and translocation in plant cells. These roles are essential for plant growth and development. AKT1 is an important K+ channel in Arabidopsis roots that is involved in K+ uptake. It is known that AKT1 is activated by a protein kinase CIPK23 interacting with two calcineurin B-like proteins CBL1/CBL9. The present study showed that another calcineurin B-like protein (CBL10) may also regulate AKT1 activity. The CBL10-over-expressing lines showed a phenotype as sensitive as that of the akt1 mutant under low-K+ conditions. In addition, the K+ content of both CBL10-over-expressing lines and akt1 mutant plants were significantly reduced compared with wild-type plants. Moreover, CBL10 directly interacted with AKT1, as verified in yeast two-hybrid, BiFC and co-immunoprecipitation experiments. The results of electrophysiological analysis in both Xenopus oocytes and Arabidopsis root cell protoplasts demonstrated that CBL10 impairs AKT1-mediated inward K+ currents. Furthermore, the results from the yeast two-hybrid competition assay indicated that CBL10 may compete with CIPK23 for binding to AKT1 and negatively modulate AKT1 activity. The present study revealed a CBL-interacting protein kinase-independent regulatory mechanism of calcineurin B-like proteins in which CBL10 directly regulates AKT1 activity and affects ion homeostasis in plant cells.
authors: State Key Laboratory of Plant Physiology and Biochemistry, National Plant Gene Research Centre (Beijing), College of Biological Sciences, China Agricultural University, #2 West Yuan Ming Yuan Road, Beijing, 100193, China.
authors: Xiao-Ling
authors: XL
authors: Ren
authors: Guo-Ning
authors: GN
authors: Qi
authors: Han-Qian
authors: HQ
authors: Feng
authors: Shuai
authors: S
authors: Zhao
authors: Shuang-Shuang
authors: SS
authors: Zhao
authors: Yi
authors: Y
authors: Wang
authors: Wei-Hua
authors: WH
authors: Wu
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D047468:Immunoprecipitation; D018408:Patch-Clamp Techniques; D016133:Polymerase Chain Reaction; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; C484078:CBL10 protein, Arabidopsis; D002135:Calcium-Binding Proteins; D015221:Potassium Channels; C074500:AKT1 protein, Arabidopsis; C514581:CIPK23 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D011188:Potassium