Signal Transduction



                                Ethylene signal transduction pathway

                                Ethylene signal transduction pathway

                                Ethylene signal transduction pathway

                                     His-kinases in Arabidopsis

                                 Response Regulators in Arabidopsis

                                Ethylene signal transduction pathway



                                   CYTOKININ – what is important?

                                             Cytokinins

                                    Effect of CK on regeneration



































                                       Games with protoplasts
                                 - Reporters for different pathways









                                   Auxin Signaling and Transport

             Discovery of the First Plant Signaling Molecule – Auxin and its Transport

AUXIN
 mediates

                                        Signal Transduction

                                        Biochemical Approach
                                             to Identify
                                           Auxin Receptor









                                    Genetic Approach to Identify
                                           Auxin Receptor







                      Molecular Biology Approach to Elucidate Auxin Signaling

                                     Molecular Biology Approach
                                    to Elucidate Auxin Signaling

                                     Some ARFs are Activators,
                                           whereas Aux/IAA
                                    Repressors of Auxin Response





                                    Summary for Auxin Signaling





                                          Auxin Transport

AUXIN TRANSPORT
mediates

                                   Physiology of Auxin Transport

                                            Auxin Influx

                                     aux1 is Resistant to Auxin

                                     NAA Rescues aux1 Phenotype

                                 AUX1 – Expression and Localization

                                            Auxin Efflux

                                  PIN1 – the Auxin Efflux Carrier?

                                      PIN2 – Root Gravitropism

                                  The Arabidopsis PIN Gene Family



                                   PINs Are Essential Components
                                         of Auxin Transport

















                                       Constitutive  Cycling
                                              of PINs

                                     PIN1 Subcellular Movement

                                  Dynamic Movement of PIN Proteins

                                       Subcellular Cycling –
                                         Means to Modulate
                                         Protein Activity?

                                   Auxin Inhibits Internalization
                                    of Plasma Membrane Proteins

                              Place of Auxin Action in Protein Cycling

                                     Auxin Inhibits Endocytosis

              Auxin Increases PIN Levels at Cell Surface and Stimulates its own Efflux



                                   Novel Pathway of Auxin Action

                                    Mutant Screen for Components
                                     of PIN Polarity and Cycling

“Cell Biological”
Mutant Screens in Progress:

Novel Pathway for Auxin Signaling