Forkhead box O (FOXO) transcription factors, the key regulators of cell survival, are negatively controlled through the PI3K-Akt signaling pathway. Phosphorylation of FOXO by Akt leads to cytoplasmic localization and subsequent degradation via the ubiquitin-proteasome system. Here we show a paradigm of FOXO1 regulation by the protein arginine methyltransferase PRMT1. PRMT1 methylated FOXO1 at conserved Arg248 and Arg250 within a consensus motif for Akt phosphorylation; this methylation directly blocked Akt-mediated phosphorylation of FOXO1 at Ser253 in vitro and in vivo. Silencing of PRMT1 by small interfering RNA enhanced nuclear exclusion, polyubiquitination, and proteasomal degradation of FOXO1. PRMT1 knockdown led to a decrease in oxidative-stress-induced apoptosis depending on the PI3K-Akt signaling pathway. Furthermore, stable expression of enzymatic inactive PRMT1 mutant increased resistance to apoptosis, whereas this effect was reversed by expression of phosphorylation-deficient FOXO1. Our findings predict a role for arginine methylation as an inhibitory modification against Akt-mediated phosphorylation.

The period (per) gene, controlling circadian rhythms in Drosophila, is expressed throughout the body in a circadian manner. A homolog of Drosophila per was isolated from rat and designated as rPer2. The rPER2 protein showed 39 and 95% amino acid identity with mPER1 and mPER2 (mouse homologs of per) proteins, respectively. A robust circadian fluctuation of rPer2 mRNA expression was discovered not only in the suprachiasmatic nucleus (SCN) of the hypothalamus but also in other tissues including eye, brain, heart, lung, spleen, liver, and kidney. Furthermore, the peripheral circadian expression of rPer2 mRNA was abolished in SCNlesioned rats that showed behavioral arrhythmicity. These findings suggest that the multitissue circadian expression of rPer2 mRNA was governed by the mammalian brain clock SCN and also suggest that the rPer2 gene was involved in the circadian rhythm of locomotor behavior in mammals.Circadian rhythms in physiology and behavior are governed by the endogenous clock (1, 2). Many circadian rhythms have been described in a diverse range of species, from bacteria to human (3). However, the common molecular mechanism of the circadian clock in diverse species is totally unknown. In mammals, the suprachiasmatic nucleus (SCN) 1 of the anterior hypothalamus has been shown to be the circadian pacemaker (1, 2). Much effort is being directed to identify the master genes that control the circadian rhythm in the SCN. One of the strong candidates is the clock gene, because a mutation in the clock gene results in arrhythmic locomotor behavior (4, 5). The period ( per) gene in Drosophila, which is expressed throughout the body in a circadian manner, regulates the circadian locomotor rhythm (6, 7). Recently two different homologs of Drosophila per gene were reported for mouse and human (8 -11). Though the two mammalian per homologs show circadian mRNA oscillation in the mouse SCN, their functional involvement in the circadian locomotor activity has not yet been reported.To examine whether a mammalian per homolog is involved in the circadian rhythm of locomotor behavior, we cloned a rat per homolog and monitored its circadian expression rhythms in peripheral tissues of SCN-lesioned rats that showed arrhythmic locomotor activity. EXPERIMENTAL PROCEDURESAnimals-Adult male Wistar rats (10 weeks old; 300 -350 g) were obtained from Clea Japan, Inc. (Tokyo) and were housed in a 12 h light-12 h dark cycle (LD12:12; lights on at zeitgeber time (ZT) 0) for at least 1 week before the day of the experiment. A white fluorescent lamp was used as a source of light during the day (150 -200 lux at the level of the cages). In this study, we killed rats in accordance with institutional guidelines.In Situ Hybridization-Animals used for in situ analysis were anesthetized with pentobarbital and were perfused from the left ventricle with 4% paraformaldehyde in phosphate-buffered saline (pH 7.4). Tissues were fixed with 4% paraformaldehyde in phosphate-buffered saline (pH 7.4) for 1 h at room temperature. Then the tissues were embedded...

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Clinical evidence suggests that antiestrogens inhibit the development of androgen-insensitive prostate cancer. Here, we show that the estrogen receptor β (ERβ) mediates inhibition by the antiestrogen ICI 182,780 (ICI) and its enhancement by estrogen. ERβ associated with gene promoters through the tumor-suppressing transcription factor KLF5 (Krüppel-like zinc finger transcription factor 5). ICI treatment increased the recruitment of the transcription coactivator CBP [CREB (adenosine 3',5'-monophosphate response element-binding protein)-binding protein] to the promoter of FOXO1 through ERβ and KLF5, which enhanced the transcription of FOXO1. The increase in FOXO1 abundance led to anoikis in prostate cancer cells, thereby suppressing tumor growth. In contrast, estrogen induced the formation of complexes containing ERβ, KLF5, and the ubiquitin ligase WWP1 (WW domain containing E3 ubiquitin protein ligase 1), resulting in the ubiquitination and degradation of KLF5. The combined presence of KLF5 and ERβ positively correlated with longer cancer-specific survival in prostate cancer patients. Our results demonstrate that estrogens and antiestrogens affect prostate tumor growth through ERβ-mediated regulation of KLF5.

PRMT8 directly hydrolyzes phosphatidylcholine, which is important for brain functions.