Two members of the thioredoxin-h family interact with the kinase domain of a Brassica S locus receptor kinase

• Published in: The Plant cell Vol. 8; no. 9; pp. 1641 - 1650
• Main Authors: Bower, M.S. (Pioneer Hi-Bred Production Ltd., Georgetown, Ontario, Canada.), Matias, D.D, Fernandes-Carvlho, E, Mazzurco, M, Gu, T, Rothstein, S.J, Goring, D.R
• Format: Journal Article
• Language: English
• Published: United States 01.09.1996
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADN; Amino Acid Sequence; ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; Arabidopsis thaliana; ARN MENSAJERO; ARN MESSAGER; AUTOESTERILIDAD; AUTOSTERILITE; Binding Sites - genetics; Brassica - genetics; Brassica - metabolism; BRASSICA NAPUS; Brassica oleracea; CHIMIORECEPTEUR; Cloning, Molecular; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; Escherichia coli; EXPERIMENTACION; EXPERIMENTATION; EXPRESION GENICA; EXPRESSION DES GENES; FLEUR; FLORES; FOSFORILACION; GINECEO; GYNECEE; INSULINA; INSULINE; Molecular Sequence Data; PHOSPHORYLATION; Plant Proteins - genetics; Plant Proteins - metabolism; Protein Kinases - genetics; Protein Kinases - metabolism; PROTEINA QUINASA; PROTEINE KINASE; QUIMIORECEPTORES; REDUCCION; REDUCTION; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; SECUENCIA NUCLEOTIDICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEOTIDIQUE; Thioredoxins - genetics; Thioredoxins - metabolism
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.8.9.1641

To determine potential targets of the S locus receptor kinase (SRK) during the Brassica self-incompatibility response, a yeast two-hybrid library was screened with the SRK-910 protein kinase domain. Two thioredoxin-h-like clones, THL-1 and THL-2, were found to interact specifically with the SRK-910 protein kinase domain and not to interact with the protein kinase domains from the Arabidopsis receptor-like protein kinases (RLK) RLK4 and RLK5. The interaction between THL-1 and the SRK-910 protein kinase domain was confirmed using coimmunoprecipitation experiments with fusion proteins produced in Escherichia coli. THL-1 has thioredoxin activity based on an insulin reduction assay, and THL-1 is weakly phosphorylated by the SRK-910 protein kinase domain. THL-1 and THL-2 are both expressed in a variety of tissues but show some differences in steady state mRNA levels, with THL-2 being preferentially expressed in floral tissues. This indicates a more general biological function for these thioredoxins in addition to a potential role as effector molecules in the self-incompatibility signal cascade