F-box only protein 21 (FBXO21)

F-box only protein 21 (FBXO21) is a member of the Fbxs subclass of F-box proteins, defined by a conserved 40-amino-acid F-box motif. As part of the SCF E3 ligase complex, FBXO21 serves as a substrate-recognition module, binding specific target proteins to mediate their polyubiquitination and subsequent proteasomal degradation. Its established substrates include EP300-inhibitor of differentiation 1 (EID1), apoptosis signal-regulating kinase 1 (ASK1), and, in the context of acute myeloid leukemia, the PI3K regulatory subunit p85α. Through controlling the abundance of these substrates, FBXO21 regulates diverse biological processes such as cell proliferation, differentiation, epithelial-to-mesenchymal transition, and immune responses. FBXO21 exhibits altered expression in several cancers; for example, reduced expression is associated with poor prognosis in gastric cancer, while low FBXO21 levels correlate with improved outcomes in leukemia. This makes FBXO21 a potential therapeutic target for modulating proteasomal degradation pathways in oncology[3][4][5][7][1][6].

Other names

F-box protein 21FBX21KIAA0875

For hypothetical drugs: Inhibition or modulation of FBXO21 could alter proteasomal degradation of substrates like p85α, EID1, and ASK1, impacting PI3K signaling, apoptosis, and differentiation in cancer cells[4][5][7].