Hundreds of plant F-box proteins in search of function

F-box proteins (FBPs), the substrate-recognition subunits of SCF (SKP1–Cullin1–F-box) E3 ubiquitin ligases, are pivotal regulators of protein turnover and play central roles in shaping cellular signaling dynamics. In plants, the repertoire of FBP-encoding genes has undergone remarkable expansion, giving rise to one of the largest and most functionally diverse protein families in the plant kingdom. This diversification underpins an extensive regulatory capacity, enabling FBPs to modulate processes such as hormone perception, developmental patterning, circadian rhythm, and responses to a wide spectrum of biotic and abiotic stresses. Here, we synthesize recent advances that illuminate the molecular mechanisms governing FBP activity, including insights into substrate recognition and their potential applications.