F-Box Protein 31 (FBXO31)

Ectopic expression of FBXO31 in 2 breast cancer cell lines inhibited colony growth on plastic and inhibited cell proliferation in the MCF-7 cell line, consistent with FBXO31 being a tumor suppressor. In addition, compared with the relative expression in normal breast, levels of FBXO31 were downregulated in breast tumor cell lines and primary tumors. In breast cell lines FBXO31 was cell cycle-regulated, with maximal expression from late G(2) to early G(1) phase; ectopic expression of FBXO31 in a breast cancer cell line resulted in the accumulation of cells at the G(1) phase of the cell cycle. FBXO31 contains an F-box domain and is associated with the proteins SKP1, ROC1, and CUL1, suggesting that FBXO31 is a component of a SCF ubiquitination complex.