MsERK1: a mitogen-activated protein kinase from a flowering plant.

Abstract

The induction of proliferation and differentiation in cultured mammalian cells is mediated by a cascade of protein phosphorylations. A key enzyme in this signaling pathway is mitogen-activated protein (MAP) kinase (or ERK, extracellular signal-regulated kinase). We report the recovery of a full-length cDNA clone encoding a MAP kinase from alfalfa. We have named the 44-kD protein encoded by this clone MsERK1. Recombinant MsERKl (rMsERKl), when overexpressed in fscherichia coli, is recognized by antibodies raised against MAP kinases from rat, Xenopus, and sea star and by antiphosphotyrosine antibodies. Site-directed mutagenesis of MsERKl demonstrated that Tyr-215 is either directly or indirectly responsible for recognition of the protein by anti-phosphotyrosine antibodies. Semipurified rMsERKl phosphorylated itself and a model substrate, myelin basic protein, in vitro, but the Tyr-215 mutant did neither. Genomic DNA gel blot analysis suggested that the gene that encodes MsERK1 is either a member of a small multigene family or a member of a polymorphic allelic series in alfalfa. Because MAP kinase activation has been associated with mitotic stimulation in animal systems, such an enzyme may play a role in the mitogenic induction of symbiotic root nodules on alfalfa by Rhizobium signal molecules.

NPK1, a tobacco gene that encodes a protein with a domain homologous to yeast BCK1, STE11, and Byr2 protein kinases.

“…6C) (9,12,30). cDNAs that encode plant homologs of MAP kinase have recently been isolated from Medicago sativa (alfalfa) (7) and Arabidopsis thaliana (35), and protein kinase activity of the product from theArabidopsis cDNA was shown to be activated by animal MAPKK (35 …”

Transient Activation and Tyrosine Phosphorylation of a Protein Kinase in Tobacco Cells Treated with a Fungal Elicitor.

“…A unique characteristic of MAP kinases is reflected in the fact that their activities are regulated by the simultaneous phosphorylation of tyrosine and threonine residues by upstream protein kinases in a conserved sequence (Payne et al, 1991;Gartner et al, 1992;Posada and Cooper, 1992). This conserved sequence has been found in all of the amino acid sequences deduced from cDNA clones for MAP kinases of plants (Duerr et al, 1993;Jonak et al, 1993;Stafstrom et al, 1993;Wilson et al, 1993;Mizoguchi et al, 1994). Wilson et al (1993) reported that a homolog of the MAP kinase in tobacco is expressed in suspension-cultured tobacco cells.…”

“…Wilson et al (1993) reported that a homolog of the MAP kinase in tobacco is expressed in suspension-cultured tobacco cells. Duerr et al (1993) demonstrated that the tyrosine residue in the conserved sequence is crucial for the activity of a recombinant MAP kinase of alfalfa expressed in Escherichia coli, and the phosphorylated tyrosine residues in the protein are recognized by a phosphotyrosinespecific antibody. However, tyrosine phosphorylation of a regulatory protein in an extract of a higher plant has rarely been detected by immunoblotting with phosphotyrosine-specific antibodies.…”

“…In severa1 plant species, the existence of the MAP kinase/extracellular signal-regulated protein kinases family has been demonstrated by the cloning of homologs, and it has been postulated that these kinases are involved in cell proliferation (Duerr et al, 1993;Jonak et al, 1993;Stafstrom et al, 1993;Wilson et al, 1993;Mizoguchi et al, 1994). Mutants of Arabidopsis are proving useful for investigations of signal transduction systems in plants, and genes for possible components of the ethylene signal transduction pathway have been identified in several recent studies.…”

Functional Roles of Plant Protein Kinases in Signal Transduction Pathways during Abiotic and Biotic Stress

“…Self-incompability [3], initiation of mitosis [4,5], isoprenoid biosynthesis [6], cytoplasmic streaming [7,8], sucrose phosphate synthase activity [9], MSERK1 activity [5] and phosphoenolpyruvate carboxylase activity [10] are the examples of regulation of cellular responses that involved protein kinases. ZmPK1 kinase with the identical extracellular domain of Slocus glycoproteins [SLG] in Brassica species is involved in the selfincompability expression in pistils [11].…”