Cytokinin Modulates Endocytic Trafficking of PIN1 Auxin Efflux Carrier to Control Plant Organogenesis

• DOI: 10.1016/j.devcel.2011.08.014
• Publication Date: 2011-09-30T12:35:56Z
• Authors: Peter Marhavý; Agnieszka Bielach; Lindy Abas; Anas Abuzeineh; Jerome Duclercq; Hirokazu Tanaka; Markéta Pařezová; Jan Petrášek; Jiří Friml; Jürgen Kleine-Vehn; Eva Benková
• Keywords: 0303 health sciences; Cytokinins; Indoleacetic Acids; Arabidopsis Proteins; Reverse Transcriptase Polymerase Chain Reaction; Organogenesis; Blotting, Western; Cell Membrane; Arabidopsis; Membrane Transport Proteins; Plant Roots; Endocytosis; Protein Transport; 03 medical and health sciences; Plant Growth Regulators; Gene Expression Regulation, Plant; RNA, Plant; Seeds; Vacuoles; RNA, Messenger; Developmental Biology

Cytokinin is an important regulator of plant growth and development. In Arabidopsis thaliana, the two-component phosphorelay mediated through a family of histidine kinases and response regulators is recognized as the principal cytokinin signal transduction mechanism activating the complex transcriptional response to control various developmental processes. Here, we identified an alternative mode of cytokinin action that uses endocytic trafficking as a means to direct plant organogenesis. This activity occurs downstream of known cytokinin receptors but through a branch of the cytokinin signaling pathway that does not involve transcriptional regulation. We show that cytokinin regulates endocytic recycling of the auxin efflux carrier PINFORMED1 (PIN1) by redirecting it for lytic degradation in vacuoles. Stimulation of the lytic PIN1 degradation is not a default effect for general downregulation of proteins from plasma membranes, but a specific mechanism to rapidly modulate the auxin distribution in cytokinin-mediated developmental processes.