Auxinbinding

Auxinbinding refers to the molecular interactions by which the plant hormone auxin binds to specific proteins and binding sites to regulate growth and development. It encompasses canonical receptor-mediated signaling as well as binding events that influence auxin distribution and availability within tissues.

In the widely supported core signaling pathway, perception occurs through the TIR1/AFB family of F-box proteins that are part of the SCF E3 ubiquitin ligase complex. When auxin is bound, these receptors gain affinity for Aux/IAA transcriptional repressors. The resulting interaction leads to ubiquitination and proteasomal degradation of Aux/IAAs, releasing auxin response factors (ARFs) to activate or repress downstream genes. The output is tightly linked to hormone concentration and tissue context, guiding processes such as cell elongation, division, and pattern formation.

Auxinbinding also relates to hormone transport, which is essential for creating auxiliary gradients. Polar auxin transport involves transporter proteins such as PIN and AUX1/LAX that bind and move auxin across cells, thereby shaping developmental patterns like organ initiation and tropic responses.

Other proteins reported to bind auxin have been described, including ABP1, which binds auxin and participates in cellular processes such as vesicle trafficking. However, the role of ABP1 as a canonical auxin receptor remains debated, and the primary, consensus pathway centers on TIR1/AFB-mediated signaling.

Overall, auxinbinding underpins a core signaling module plus transport-related interactions that together coordinate plant growth, development, and adaptive responses.