FBX5 Regulator of APC activity during mitotic and meiotic cell cycle. During mitotic cell cycle plays a role as both substrate and inhibitor of APC-FZR1 complex. During G1 phase, plays a role as substrate of APC-FZR1 complex E3 ligase. Then switches as an inhibitor of APC-FZR1 complex during S and G2 leading to cell-cycle commitment. As APC inhibitor, prevents the degradation of APC substrates at multiple levels: by interacting with APC and blocking access of APC substrates to the D-box coreceptor, formed by FZR1 and ANAPC10; by suppressing ubiquitin ligation and chain elongation by APC by preventing the UBE2C and UBE2S activities. Plays a role in genome integrity preservation by coordinating DNA replication with mitosis through APC inhibition in interphase to stabilize CCNA2 and GMNN in order to promote mitosis and prevent rereplication and DNA damage-induced cellular senescence. During oocyte maturation, plays a role in meiosis through inactivation of APC-FZR1 complex. Inhibits APC through RPS6KA2 interaction that increases FBXO5 affiniy for CDC20 leading to the metaphase arrest of the second meiotic division before fertilization. Controls entry into the first meiotic division through inactivation of APC-FZR1 complex. Promotes migration and osteogenic differentiation of mesenchymal stem cells. 2 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Chromosomal Location of Human Ortholog: 6q25.2
Cellular Component:  cytoplasm; cytosol; meiotic spindle; nucleoplasm; nucleus; spindle
Molecular Function:  anaphase-promoting complex binding; metal ion binding; protein binding; protein kinase binding; ubiquitin ligase inhibitor activity
Biological Process:  anaphase-promoting complex-dependent catabolic process; cell division; microtubule polymerization; negative regulation of cellular senescence; negative regulation of DNA endoreduplication; negative regulation of mitotic metaphase/anaphase transition; negative regulation of response to DNA damage stimulus; negative regulation of ubiquitin protein ligase activity; negative regulation of ubiquitin-protein transferase activity; oocyte maturation; positive regulation of biomineral tissue development; positive regulation of cell proliferation; positive regulation of G2/M transition of mitotic cell cycle; positive regulation of mesenchymal stem cell migration; positive regulation of osteoblast differentiation; protein ubiquitination; regulation of DNA replication; regulation of mitotic cell cycle; regulation of mitotic cell cycle phase transition; regulation of transcription involved in G1/S transition of mitotic cell cycle; spindle assembly involved in female meiosis I; vesicle organization
Reference #:  Q9UKT4 (UniProtKB)
Alt. Names/Synonyms: Early mitotic inhibitor 1; EMI1; F-box only protein 5; F-box protein 5; F-box protein Fbx5; FBX5; Fbxo31; FBXO5
Gene Symbols: FBXO5
Molecular weight: 50,146 Da
Basal Isoelectric point: 9.17  Predict pI for various phosphorylation states
Select Structure to View Below


Protein Structure Not Found.

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