The TMK1 gene from Arabidopsis codes for a protein with structural and biochemical characteristics of a receptor protein kinase.

Abstract

Genomic and cDNA clones that code for a protein with structural and biochemical properties similar to the receptor protein kinases from animals were obtained from Arabidopsis. Structural features of the predicted polypeptide include an amino-terminal membrane targeting signal sequence, a region containing blocks of leucine-rich repeat elements, a single putative membrane spanning domain, and a characteristic serinehhreonine-specific protein kinase domain. The gene coding for this receptor-like transmembrane kinase was designated TMK1. Portions of the TMKl gene were expressed in Escherichia coli, and antibodies were raised against the recombinant polypeptides. These antibodies immunodecorated a 120-kD polypeptide present in crude extracts and membrane preparations. The immunodetectable band was present in extracts from leaf, stem, root, and floral tissues. The kinase domain of TMKl was expressed as a fusion protein in E. coli, and the purified fusion protein was found capable of autophosphorylation on serine and threonine residues. The possible role of the TMKl gene product in transmembrane signaling is discussed.

Recombinant Brassinosteroid Insensitive 1 Receptor-Like Kinase Autophosphorylates on Serine and Threonine Residues and Phosphorylates a Conserved Peptide Motif in Vitro

“…Pairwise alignment of BRI1-KD with other receptor-like kinases did not reveal any obvious motif that would predict whether the kinases autophosphorylated primarily on Ser or Thr. For example, based on BLASTP alignment scores and sequence identity, CrRLK1 (Schulze-Muth et al, 1996) and TMK1 (Chang et al, 1992), which autophosphorylate predominantly on Thr, were as closely related to BRI1 as RLK5 and CLV1 (Stone et al, 1998), both of which have a preference for Ser. Nor was the type of extracellular domain any predictor of Ser versus Thr autophosphorylation, with both Leu-rich repeat and S locus-type glycoprotein domains occurring in receptor-like kinases that preferred either Ser or Thr.…”

“…However, other plant receptor-like kinases have either an equal propensity for autophosphorylation on Ser and Thr, i.e. RKF1 (Takahashi et al, 1998), or have a preference for Thr over Ser, including CrRLK1 (SchulzeMuth et al, 1996), TMK1 (Chang et al, 1992), SRK (Goring and Rothstein, 1992), KIK1 (Braun et al, 1997), RLK4 (Coello et al, 1999), and OsTMK (van der Knaap et al, 1999). A petunia receptor-like kinase has been described that apparently is a dual-function kinase that phosphorylates both Ser and Tyr residues (Mu et al, 1994).…”

Developmental and age-related processes that influence the longevity and senescence of photosynthetic tissues in arabidopsis.

“…The %Aabeled tracer was made from the 1.15-kb Hindlll fragment of the 5'end of the TMK7 gene (Chang et al, 1992), which was cloned into the pGEM-7 plasmid (Promega). In vitro transcription from the SP6 promoter (Riboprobe kit; Promega) produced 35S-labeled RNA of -1 kb in length.…”

Xa21D Encodes a Receptor-Like Molecule with a Leucine-Rich Repeat Domain That Determines Race-Specific Recognition and Is Subject to Adaptive Evolution

“…The largest subclass of plant RKs is the leucine-rich repeat (LRR) group, which encodes proteins with an extracellular domain containing 20 to 25 imperfect repeats of a 24-amino acid leucine-rich motif. The LRR subclass of plant RKs includes proteins that govern pollen development, plant elongation, regulation of meristem and flower development, disease resistance, and brassinosteroid signal transduction, as well as other functions that remain to be determined (Chang et al, 1992;Valon et al, 1993; Song et al, 1995;Torii et al, 1996;Clark et al, 1997;Li and Chory, 1997). Plant LRRs have also been found in secreted proteins (polygalacturonase inhibitor proteins or PGIPs) (De Lorenzo et al, 1994) and in membrane-bound resistance gene products (Dixon et al, 1996).…”