title: Two members of the thioredoxin-h family interact with the kinase domain of a Brassica S locus receptor kinase.
abstract: 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.
authors.affiliation: Biology Department, York University, Ontario, Canada.
authors.forename: M S
authors.initials: MS
authors.lastname: Bower
authors.forename: D D
authors.initials: DD
authors.lastname: Matias
authors.forename: E
authors.initials: E
authors.lastname: Fernandes-Carvalho
authors.forename: M
authors.initials: M
authors.lastname: Mazzurco
authors.forename: T
authors.initials: T
authors.lastname: Gu
authors.forename: S J
authors.initials: SJ
authors.lastname: Rothstein
authors.forename: D R
authors.initials: DR
authors.lastname: Goring
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D001937:Brassica / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D013879:Thioredoxins; D011494:Protein Kinases; C079832:S-receptor kinase