Figure 3.

The regulation of biological activities by F-box proteins implicated in human cancer. The schematics depict the impact of various F-box proteins that are known to be deregulated in human cancer on cellular processes relevant to the tumorigenic phenotype, including the cell cycle (A and B; with A: positive role in proliferation, with potential oncogenic F-box proteins, and B: with inhibitory role on proliferation, with potential tumor-suppressing role), cell survival (C), invasion and metastasis (D) as well as those that regulate the integrity of the genome (E). Positive regulators of cell proliferation, survival and metastasis are depicted in light red ovals, and those that negatively impact these processes in light blue. Some of these F-box proteins are represented more than once to highlight their involvement in the various biological activities. Factors which impact genomic stability are shown in orange ovals. The SCF ligase with the various F-box protein substrate receptors directs the ubiquitin-dependent proteasomal degradation of substrates to regulate these processes. Although they assemble SCF ligases, FBXL10, FBXO18 and cyclin F exhibit functions that are yet to be shown to require their assembly into SCF ligases, and as such are depicted as single subunits.