Transport inhibitor response 1 (TIR1) (TIR1)

Transport inhibitor response 1 (TIR1) is a specialized F-box protein that functions as a primary receptor for the plant hormone auxin, specifically indole-3-acetic acid (IAA) [UniProt: P93004]. It serves as a critical component of the SCF (Skp1-Cullin-F-box) E3 ubiquitin ligase complex, where it operates through a unique molecular glue mechanism [PubMed: 15917807]. Upon binding auxin, TIR1 recruits Aux/IAA transcriptional repressor proteins, leading to their polyubiquitination and subsequent degradation by the 26S proteasome [PubMed: 15917808]. This process is fundamental to plant growth, regulating gene expression patterns that drive development and environmental responses. In the field of biotechnology, the TIR1-auxin interaction has been adapted into the Auxin-Inducible Degron (AID) system, enabling researchers to achieve rapid and reversible depletion of target proteins in non-plant cells, including human models [PubMed: 21964334]. This system is currently a vital tool for functional genomics and serves as a prototype for the development of novel molecular glue degraders in human medicine [PubMed: 31548606].

Other names

F-box protein TIR1Auxin receptor TIR1SCF-TIR1

Acts as a molecular glue receptor that, upon binding auxin, recruits Aux/IAA repressor proteins to the SCF-TIR1 E3 ubiquitin ligase complex for ubiquitination and subsequent proteasomal degradation [PubMed: 15917807].