Ligand-receptor pairs in plant peptide signaling.
Extensive studies on plant signaling molecules over the past decade indicate that plant cell-to-cell communication, as is the case with animal systems, makes use of small peptide signals and specific receptors. To date, four peptide-ligand-receptor pairs have been identified and shown to be involved in a variety of processes. Systemin and phytosulfokine (PSK), the first and second signaling peptides identified in plants, were isolated by biochemical purification based on their biological activities. Furthermore, their receptors have been biochemically purified from plasma membranes on the basis of specific ligand-receptor interactions. By contrast, the two other peptide signals, CLAVATA3 (CLV3) and the pollen S determinant SCR/SP11, were genetically identified during searches for specific ligands for receptors that had already been cloned. Systemin functions in the plant wound response, whereas PSK appears to cooperate with auxin and cytokinin to regulate cellular dedifferentiation and redifferentiation. CLV3 is important for meristem organization, binding to a heterodimeric receptor comprising the CLV1 and CLV2 proteins. SCR/SP11 instead plays a role in self-incompatibility, where it activates a signalling cascade that leads to rejection of pollen with the same S haplotype. These ligands all seem to bind to receptors that possess intrinsic kinase activity, and al least two of them are generated by proteolytic processing of larger precursor proteins.
Matsubayashi
Yoshikatsu
Y
Graduate School of Bio-Agricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan. matsu@agr.nagoya-u.ac.jp
D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002450:Cell Communication; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism*; D003583:Cytokinins / Q000378:metabolism; D004789:Enzyme Activation / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000378:metabolism*; D011058:Pollen / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D011956:Receptors, Cell Surface / Q000378:metabolism*
C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; C401621:CLV2 protein, Arabidopsis; D003583:Cytokinins; D007210:Indoleacetic Acids; D008024:Ligands; D008565:Membrane Proteins; D010455:Peptides; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C431526:SP11 protein, Brassica; C073704:systemin; D011494:Protein Kinases; D020794:Receptor Protein-Tyrosine Kinases; C118166:CLV1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases