sentences:  F-box domains commonly exist in proteins in concert with other protein–protein interaction motifs such as leucine-rich repeats (illustrated in the Figure) and WD repeats, which are thought to mediate interactions with SCF substrates.F-box proteins have also been associated with cellular functions such as signal transduction and regulation of the cell cycle.In plants, many F-box proteins are represented in gene networks broadly regulated by microRNA-mediated gene silencing via RNA interference.