FOXO3A, phosphorylated (Ser294) (Forkhead Box O3A, FOXO3, AF6q21 Protein, Forkhead in Rhabdomyosarcoma-like 1, FKHRL1, FKHRL1P2, MGC12739, MGC31925)

The Forkhead family of transcription factors is involved in tumorigenesis of rhabdomyosarcoma and acute leukemias (1-3). Within the family, three members (FoxO1, FoxO4 and FoxO3a) have sequence similarity to the nematode orthologue DAF-16, which mediates signaling via a pathway involving IGFR1, PI3K and Akt (4-6). Active forkhead members act as tumor suppressors by promoting cell cycle arrest and apoptosis. Increased expression of any FoxO member results in the activation of the cell cycle inhibitor p27Kip1. Forkhead transcription factors also play a part in TGF-B-mediated upregulation of p21CIP1, a process negatively regulated through PI3K (7). Increased proliferation results when forkhead transcription factors are inactivated through phosphorylation by Akt at Thr24, Ser256 and Ser319, which results in nuclear export and inhibition of transcription factor activity (8). Forkhead transcription factors can also be inhibited by the deacetylase sirtuin (SirT1) (9). Erk phosphorylates FoxO3a at Ser294, Ser344 and Ser425, resulting in degradation of FoxO3a through the MDM2-mediated ubiquitin-proteasome pathway. Thus, Erk promotes proliferation and tumor progression by inhibiting FoxO3a (10). Applications: Suitable for use in Western Blot and Immunoprecipitation. Other applications not tested. Recommended Dilution: Western Blot: 1:1000 Incubate membrane with diluted antibody in 5% BSA, 1X TBS, 0.1% Tween-20 at 4 degrees C with gentle shaking, overnight. Immunoprecipitation: 1:50 Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.