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14‐3‐3 proteins activate a plant calcium‐dependent protein kinase (CDPK)
Author(s) -
Camoni Lorenzo,
Harper Jeffrey F,
Palmgren Michael G
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00696-6
Subject(s) - calmodulin , gene isoform , kinase , biochemistry , fusion protein , 14 3 3 protein , arabidopsis thaliana , signal transduction , arabidopsis , microbiology and biotechnology , biology , protein kinase a , chemistry , recombinant dna , enzyme , phosphorylation , gene , mutant
Plants and protozoa contain a unique family of calcium‐dependent protein kinases (CDPKs) which are defined by the presence of a carboxyl‐terminal calmodulin‐like regulatory domain. We present biochemical evidence indicating that at least one member of this kinase family can be stimulated by 14‐3‐3 proteins. Isoform CPK‐1 from the model plant Arabidopsis thaliana was expressed as a fusion protein in E. coli and purified. The calcium‐dependent activity of this recombinant CPK‐1 was shown to be stimulated almost twofold by three different 14‐3‐3 isoforms with 50% activation around 200 nM. 14‐3‐3 proteins bound to the purified CPK‐1, as shown by binding assays in which either the 14‐3‐3 or CPK‐1 were immobilized on a matrix. Both the 14‐3‐3 binding and activation of CPK‐1 were specifically disrupted by a known 14‐3‐3 binding peptide LSQRQRSTpSTPNVHMV (IC 50 =30 μM). These results raise the question of whether 14‐3‐3 can modulate the activity of CDPK signal transduction pathways in plants.