TIR1 is a core component of the auxin signaling pathway in plants, belonging to the F-box protein family and part of the SCF complex. Its primary function is to recognize and promote the ubiquitination and subsequent degradation of specific target proteins within the auxin signaling pathway. TIR1 and its homologs, AFBs, form a family that plays a crucial role in plant perception and response to auxin. These proteins are located in the nucleus and affect plant growth and development by regulating the expression of auxin-responsive genes. The expression levels and mutations of the TIR1 gene directly influence auxin signal transmission, thereby affecting plant morphology.