Phytohormones Participate in an S6 Kinase Signal Transduction Pathway in Arabidopsis1

AUTOR(ES)

Turck, Franziska

FONTE

American Society of Plant Biologists

RESUMO

Addition of fresh medium to stationary cells of Arabidopsis suspension culture induces increased phosphorylation of the S6 ribosomal protein and activation of its cognate kinase, AtS6k. Analysis of the activation response revealed that medium constituents required for S6 kinase activation were the phytohormones 1-naphthylacetic acid (auxin) and kinetin. Pretreatment of cells with anti-auxin or PI3-kinase drugs inhibited this response. Consistent with these findings, LY294002, a PI3-kinase inhibitor, efficiently suppressed phytohormone-induced S6 phosphorylation and translational up-regulation of ribosomal protein S6 and S18A mRNAs without affecting global translation. These data indicate that (1) activation of AtS6k is regulated by phytohormones, at least in part, via a lipid kinase-dependent pathway, that (2) the translational regulation of ribosomal proteins appears to be conserved throughout the plant and animal kingdom, and that (3) these events are hallmarks of a growth-related signal transduction pathway novel in plants.

Documentos Relacionados

• Two-Component Signal Transduction Pathways in Arabidopsis1
• Recruitment of the Extracellular Signal-Regulated Kinase/Ribosomal S6 Kinase Signaling Pathway to the NFATc4 Transcription Activation Complex
• Transgene Expression Patterns Indicate That Spaceflight Affects Stress Signal Perception and Transduction in Arabidopsis1
• Phosphorylation of p90 Ribosomal S6 Kinase (RSK) Regulates Extracellular Signal-Regulated Kinase Docking and RSK Activity
• A stimulated S6 kinase from rat liver: identity with the mitogen activated S6 kinase of 3T3 cells.