StCDPK2 expression and activity reveal a highly responsive potato calcium-dependent protein kinase involved in light signalling.
Calcium-dependent protein kinases (CDPKs) are essential calcium sensors. In this work, we have studied StCDPK2 isoform from potato both at gene and protein level. StCdpk2 genomic sequence contains eight exons and seven introns, as was observed for StCdpk1. There is one copy of the gene per genome located in chromosome 7. StCDPK2 encodes an active CDPK of 515 aminoacids, with an apparent MW of 57 kDa, which presents myristoylation and palmitoylation consensus in its N-terminus. StCDPK2 is highly expressed in leaves and green sprouts; enhanced expression was detected under light treatment, which corresponds well with light responsive cis-acting elements found in its promoter sequence. Antibodies against the recombinant StCDPK2::6xHis protein detected this isoform in soluble and particulate fractions from leaves. StCDPK2 autophosphorylation and kinase activity are both calcium dependent reaching half maximal activation at 0.6 μM calcium. The active kinase is autophosphorylated on serine and tyrosine residues and its activity is negatively modulated by phosphatidic acid (PA). Our results reveal StCDPK2 as a signalling element involved in plant growth and development and show that its activity is tightly regulated.
Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), CONICET and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Vuelta de Obligado 2490 2do piso, 1428, Buenos Aires, Argentina.
Verónica
V
Giammaria
Carolina
C
Grandellis
Sandra
S
Bachmann
Pablo Rubén
PR
Gargantini
Sergio Enrique
SE
Feingold
Glenn
G
Bryan
Rita María
RM
Ulloa
D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008027:Light; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics; D011198:Solanum tuberosum / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D015854:Up-Regulation; D017871:Calcium-Calmodulin-Dependent Protein Kinases
D002118:Calcium; D002135:Calcium-Binding Proteins; D010940:Plant Proteins; D020033:Protein Isoforms; D011494:Protein Kinases; D011994:Recombinant Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases