title: The Arabidopsis Ca(2+) -dependent protein kinase CPK12 negatively regulates abscisic acid signaling in seed germination and post-germination growth.
abstract: • Ca(2+) -dependent protein kinase (CDPK) is believed to be involved in abscisic acid (ABA) signaling, and several members of the Arabidopsis CDPK superfamily have been identified as positive ABA signaling regulators, but it remains unknown if CDPK negatively regulates ABA signaling. • Here, we investigated the function of an Arabidopsis (Arabidopsis thaliana) CDPK, CPK12, in ABA signaling pathway. • We generated Arabidopsis CPK12-RNAi lines, and observed that downregulation of CPK12 resulted in ABA hypersensitivity in seed germination and post-germination growth, and altered expression of a set of ABA-responsive genes. Expression assay showed that CPK12 was ubiquitously expressed and localized to both cytosol and nucleus. Biochemical assays showed that CPK12 interacted with, phosphorylated and stimulated a type 2C protein phosphatase ABI2, and phosphorylated two ABA-responsive transcription factors (ABF1 and ABF4) in vitro. • Our findings show that the Arabidopsis CPK12 is a negative ABA-signaling regulator in seed germination and post-germination growth, suggesting that different members of the CDPK family may constitute a regulation loop by functioning positively and negatively in ABA signal transduction.
authors.affiliation: College of Biological Sciences, China Agricultural University, 100094 Beijing, China.|Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhao
authors.affiliation: College of Biological Sciences, China Agricultural University, 100094 Beijing, China.|Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Hai-Li
authors.initials: HL
authors.lastname: Sun
authors.affiliation: Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Mei
authors.affiliation: College of Biological Sciences, China Agricultural University, 100094 Beijing, China.|Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Xiao-Jing
authors.initials: XJ
authors.lastname: Wang
authors.affiliation: College of Biological Sciences, China Agricultural University, 100094 Beijing, China.|Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Yan
authors.affiliation: College of Biological Sciences, China Agricultural University, 100094 Beijing, China.|Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Liu
authors.affiliation: Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Zhang
authors.affiliation: College of Biological Sciences, China Agricultural University, 100094 Beijing, China.|Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Wang
authors.affiliation: Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, 100084 Beijing, China.
authors.forename: Da-Peng
authors.initials: DP
authors.lastname: Zhang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D015536:Down-Regulation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D018525:Germination / Q000187:drug effects / Q000235:genetics; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D034622:RNA Interference / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology; D013379:Substrate Specificity / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases; D011494:Protein Kinases; D012333:RNA, Messenger; D014157:Transcription Factors; C568892:CPK12 protein, Arabidopsis; C106443:ABI2 protein, Arabidopsis