The Biological Function and Roles in Phytohormone Signaling of the F-Box Protein in Plants

The ubiquitin–proteasome pathway (UPP) is an important protein degradation pathway that can participate in the regulation of the physiological process of organisms by specifically removing abnormal peptides and degrading cell regulators. UPP mainly involves three enzymes, among which the E3 ubiquitin ligase function is central to UPP. E3 ubiquitin ligases can recruit substrate protein for ubiquitination, and they have various forms. Among them, the Skp1–Cul1–F-box (SCF) complex is the most representative member of the cullin RING ubiquitin ligases type in RING-domain E3 ligases, being mainly composed of Cullin 1, Skp1, Rbx1, and F-box proteins. The F-box protein is the key component for SCF to perform specific functions. The F-box protein is one of the largest protein families in plants, and its family members are involved in the regulation of many key physiological processes, such as growth and development of plants and the response to external stimuli. Herein, we briefly review the structure, classification, function, and hormone signaling pathways of F-box proteins.