Abstract
Recent progress on auxin signaling study revealed fundamental molecular mechanism of auxin signaling mediated by SCF(TIR1)-proteasome pathway. In this pathway, auxin was perceived by TIR1/AFB auxin receptor and leads to an SCF ubiquitin-ligase catalyzed degradation of Aux/IAA transcriptional repressors. In addition to SCF(TIR1) auxin signaling, Auxin Binding Protein 1 (ABP1) is believed to be involved in alternative auxin signaling. Auxin Binding Protein 1 (ABP1) was identified as auxin receptor candidate and its physiological role have been extensively studied. However, the detailed physiological function of ABP1 and ABP1 mediated auxin signaling is still unknown. Therefore, ABP1 specific chemical probe would be useful tool to investigate ABP1 function and its involved signaling. We designed ABP1 probe on the basis of ABP1 and TIR1 crystal structures, and synthesized some ABP1 probes. Some designed ABP1 probes showed the promotion on hypocotyl elongation without activating SCF(TIR1)-mediated gene expression. In comparison with the Arabidopsis phenotype treated with various known auxins, these probes exhibited different effects on Arabidopsis from known auxin effects.
