title: Interactions in the pollen-specific receptor-like kinases-containing signaling network.
abstract: The pollen-specific receptor-like kinases (PRKs) from Solanum lycopersicum, LePRK1 and LePRK2, are believed to be involved in the regulation of pollen germination and pollen tube growth. They appear to be part of a multimeric complex in which the transmembranic LePRKs presumably have a key position in transducing exogenous signals through the plasma membrane. Here, we focused on extra- and intracellular interactions involving the LePRKs. We show in yeast two-hybrid experiments a cross-interaction of putative PRK-ligands, the oligomerization of LePRK2 and a direct contact of LePRKs to activated Rho proteins of plants (ROPs). Moreover, we observed that pollen-specific RopGEFs, which catalyze ROP activation and may be regulated by PRK interaction, are active in vitro while autoinhibition seems to occur in vivo. We suggest that activation of RopGEFs as a checkpoint in PRK signal transduction is a more complex event including further components in planta. Our findings point to some new aspects in PRK-mediated signal transduction implying a LePRK2 complex with different signaling activity and a further direct control of LePRKs by activated ROP.
authors.affiliation: Max Planck Institute of Molecular Physiology, Structural Biology Department, Otto Hahn Strasse 11, 44227 Dortmund, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Löcke
authors.forename: Inka
authors.initials: I
authors.lastname: Fricke
authors.forename: Elena
authors.initials: E
authors.lastname: Mucha
authors.forename: Marie-Luise
authors.initials: ML
authors.lastname: Humpert
authors.forename: Antje
authors.initials: A
authors.lastname: Berken
mesh_terms: D018551:Solanum lycopersicum / Q000201:enzymology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000235:genetics / Q000378:metabolism; D053205:Pollen Tube / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization / Q000235:genetics / Q000502:physiology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D011494:Protein Kinases; D020741:rho GTP-Binding Proteins