The phytohormone auxin triggers transcriptional reprogramming through a well-characterized perception machinery in the nucleus. By contrast, mechanisms that underlie fast effects of auxin, such as the regulation of ion fluxes, rapid phosphorylation of proteins or auxin feedback on its transport, remain unclear1-3. Whether auxin-binding protein 1 (ABP1) is an auxin receptor has been a source of debate for decades1,4. Here we show that a fraction of Arabidopsis thaliana ABP1 is secreted and binds auxin specifically at an acidic pH that is typical of the apoplast. ABP1 and its plasma-membrane-localized partner, transmembrane kinase 1 (TMK1), are required for the auxin-induced ultrafast global phospho-response and for downstream processes that include the activation of H+-ATPase and accelerated cytoplasmic streaming. abp1 and tmk mutants cannot establish auxin-transporting channels and show defective auxin-induced vasculature formation and regeneration. An ABP1(M2X) variant that lacks the capacity to bind auxin is unable to complement these defects in abp1 mutants. These data indicate that ABP1 is the auxin receptor for TMK1-based cell-surface signalling, which mediates the global phospho-response and auxin canalization.

• MeSH
• Arabidopsis * genetika   metabolismus   MeSH
• fosforylace MeSH
• koncentrace vodíkových iontů MeSH
• kyseliny indoloctové * metabolismus   MeSH
• mutace MeSH
• protein-serin-threoninkinasy * genetika   metabolismus   MeSH
• proteiny huseníčku * genetika   metabolismus   MeSH
• protonové ATPasy metabolismus   MeSH
• proudění cytoplazmy MeSH
• regulátory růstu rostlin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• AT1G66150 protein, Arabidopsis MeSH Prohlížeč
• auxin-binding protein 1 MeSH Prohlížeč
• kyseliny indoloctové * MeSH
• protein-serin-threoninkinasy * MeSH
• proteiny huseníčku * MeSH
• protonové ATPasy MeSH
• regulátory růstu rostlin MeSH