The FOXO forkhead transcription factors are involved in metabolism control, cell survival, cellular proliferation, DNA damage repair response, and stress resistance. Their transcriptional activity is regulated through a number of posttranslational modifications, including phosphorylation, acetylation and ubiquitination. The recently determined three-dimensional structures of FOXO forkhead domains bound to DNA enable to explain the structural basis for DNA recognition by FOXO proteins and its regulation. The aim of this review is to summarize the recent structural characterization of FOXO proteins, the mechanisms of DNA recognition and the role of posttranslational modifications in the regulation of FOXO DNA-binding properties. This article is part of a Special Issue entitled: PI3K-AKT-FOXO axis in cancer and aging.

• MeSH
• DNA chemie   metabolismus   MeSH
• forkhead transkripční faktory chemie   metabolismus   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• terciární struktura proteinů MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

The FOXO subgroup of forkhead transcription factors plays a central role in cell-cycle control, differentiation, metabolism control, stress response and apoptosis. Therefore, the function of these important molecules is tightly controlled by a wide range of protein-protein interactions and posttranslational modifications including phosphorylation, acetylation and ubiquitination. The mechanisms by which these processes regulate FOXO activity are mostly elusive. This review focuses on recent advances in structural studies of forkhead transcription factors and the insights they provide into the mechanism of DNA recognition. On the basis of these data, we discuss structural aspects of protein-protein interactions and posttranslational modifications that target the forkhead domain and the nuclear localization signal of FOXO proteins.

• MeSH
• acetylace MeSH
• financování organizované MeSH
• forkhead transkripční faktory fyziologie   chemie   MeSH
• fosforylace MeSH
• konformace proteinů MeSH
• lidé MeSH
• posttranslační úpravy proteinů MeSH
• ubikvitin metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• přehledy MeSH

FOXO transcription factors regulate cellular homeostasis, longevity and response to stress. FOXO1 (also known as FKHR) is a key regulator of hepatic glucose production and lipid metabolism, and its specific inhibition may have beneficial effects on diabetic hyperglycemia by reducing hepatic glucose production. Moreover, all FOXO proteins are considered potential drug targets for drug resistance prevention in cancer therapy. However, the development of specific FOXO inhibitors requires a detailed understanding of structural differences between individual FOXO DNA-binding domains. The high-resolution structure of the DNA-binding domain of FOXO1 reported in this study and its comparison with structures of other FOXO proteins revealed differences in both their conformation and flexibility. These differences are encoded by variations in protein sequences and account for the distinct functions of FOXO proteins. In particular, the positions of the helices H1, H2 and H3, whose interface form the hydrophobic core of the Forkhead domain, and the interactions between hydrophobic residues located on the interface between the N-terminal segment, the H2-H3 loop, and the recognition helix H3 differ among apo FOXO1, FOXO3 and FOXO4 proteins. Therefore, the availability of apo structures of DNA-binding domains of all three major FOXO proteins will support the development of FOXO-type-specific inhibitors.

• MeSH
• forkhead box protein O1 chemie   genetika   metabolismus   MeSH
• forkhead transkripční faktory chemie   genetika   metabolismus   MeSH
• hydrofobní a hydrofilní interakce MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární modely MeSH
• myši MeSH
• protein FOXO3 chemie   genetika   metabolismus   MeSH
• proteinové domény MeSH
• sekundární struktura proteinů MeSH
• sekvenční analýza proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

FOXO4 is a member of the FOXO subgroup of forkhead transcription factors that constitute key components of a conserved signalling pathway that connects growth and stress signals to transcriptional control. Here, the 1.9 Å resolution crystal structure of the DNA-binding domain of human FOXO4 (FOXO4-DBD) bound to a 13 bp DNA duplex containing a FOXO consensus binding sequence is reported. The structure shows a similar recognition of the core sequence as has been shown for two other FOXO proteins. Helix H3 is docked into the major groove and provides all of the base-specific contacts, while the N-terminus and wing W1 make additional contacts with the phosphate groups of DNA. In contrast to other FOXO-DBD-DNA structures, the loop between helices H2 and H3 has a different conformation and participates in DNA binding. In addition, the structure of the FOXO4-DBD-DNA complex suggests that both direct water-DNA base contacts and the unique water-network interactions contribute to FOXO-DBD binding to the DNA in a sequence-specific manner.

• MeSH
• DNA chemie   metabolismus   MeSH
• konformace nukleové kyseliny MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• strukturní homologie proteinů MeSH
• terciární struktura proteinů MeSH
• transkripční faktory chemie   metabolismus   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• aktivace transkripce genetika   MeSH
• Caenorhabditis elegans chemie   metabolismus   MeSH
• forkhead transkripční faktory genetika   metabolismus   MeSH
• proteiny Caenorhabditis elegans genetika   metabolismus   MeSH
• receptory cytoplazmatické a nukleární fyziologie   genetika   MeSH
• regulace genové exprese genetika   MeSH
• represorové proteiny fyziologie   genetika   MeSH

• Publikační typ
• abstrakt z konference MeSH

Jako sarkopenie se označuje úbytek hmotnosti, který se vyskytuje ve vyšším věku při nedostatečné výživě a týká se především kosterního svalstva. Od sarkopenie je třeba odlišit kachexii, při níž má úbytek hmotnosti kauzální spojitost se závažnými chorobami, např. maligními nádory, chronickým srdečním selháním nebo AIDS. Výstavbu svalů stimulují správná výživa a pravidelná fyzická aktivita, jakož i anabolické hormony a růstové faktory, kdežto k jejich odbourávání přispívají prozánětlivé cytokiny a myostatin. Inzulinu podobný růstový faktor 1 (IGF-1), dostupnost aminokyselin a fyzická aktivita zvyšují syntézu proteinů ve svalech aktivací proteinkináz (Akt, mTOR). Prozánětlivé cytokiny a myostatin zvyšují odbourávání svalových proteinů tím, že aktivují některé transkripční faktory (např. NF?B, FoxO) stimulující syntézu příslušných proteolytických enzymů (ubiquitin ligáz E3).

Als Sarkopenie bezeichnet man den bei Mangelernahrung und im Alter auftretenden Gewichtsverlust. Er betrifft vor allem die Skelettmuskulatur. Davon abzugrenzen ist die Kachexie, bei der ein Gewichtsverlust im Zusammenhang mit Krankheiten wie beispielsweise Krebs, chronischer Herzinsuffizienz oder AIDS auftritt. Richtige Ernahrung, Beanspruchung der Muskulatur, anabole Hormone und Wachstumsfaktoren beeinflussen den Muskelaufbau positiv, wahrend Entzundungszytokine und Myostatin den Abbau fordern. Der Insulin-like growth factor 1 (IGF-1), die Aminosaureverfugbarkeit und Bewegung steigern die Proteinsynthese im Muskel uber die Aktivierung von Proteinkinasen (Akt, mTOR). Entzundungszytokine und Myostatin fordern den Abbau von Muskelproteinen uber die Aktivierung von Transkriptionsfaktoren (NF?B, FoxO). Diese stimulieren die Synthese von Enyzmen, die den Proteinabbau einleiten (E3-Ubiquitinligasen),

• Klíčová slova
• Sarcopenia,
• MeSH
• cvičení MeSH
• diferenciální diagnóza MeSH
• hmotnostní úbytek MeSH
• insulinu podobný růstový faktor I MeSH
• kachexie MeSH
• kosterní svaly MeSH
• lidé MeSH
• mediátory zánětu MeSH
• myostatin MeSH
• plošný screening MeSH
• protein-energetická malnutrice MeSH
• proteoglykany MeSH
• reaktivní formy kyslíku MeSH
• senioři MeSH
• signální transdukce MeSH
• svalová atrofie MeSH
• věkové faktory MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• přehledy MeSH

The 14-3-3 proteins are a family of regulatory signaling molecules that interact with other proteins in a phosphorylation-dependent manner. 14-3-3 proteins are thought to play a direct role in the regulation of subcellular localization of FoxO forkhead transcription factors. It has been suggested that the interaction with the 14-3-3 protein affects FoxO binding to the target DNA and interferes with the function of nuclear localization sequence (NLS). Masking or obscuring of NLS could inhibit interaction between FoxO factors and nuclear importing machinery and thus shift the equilibrium of FoxO localization toward the cytoplasm. According to our best knowledge, there is no experimental evidence showing a direct interaction between the 14-3-3 protein and NLS of FoxO. Therefore, the main goal of this work was to investigate whether the phosphorylation by protein kinase B, the 14-3-3 protein, and DNA binding affect the structure of FoxO4 NLS. We have used site-directed labeling of FoxO4 NLS with the extrinsic fluorophore 1,5-IAEDANS in conjunction with steady-state and time-resolved fluorescence spectroscopy to study conformational changes of FoxO4 NLS in vitro. Our data show that the 14-3-3 protein binding significantly changes the environment around AEDANS-labeled NLS and reduces its flexibility. On the other hand, the phosphorylation itself and the binding of double-stranded DNA have a small effect on the structure of this region. Our results also suggest that the DNA-binding domain of FoxO4 remains relatively mobile while bound to the 14-3-3 protein.

• MeSH
• financování organizované MeSH
• fluorescenční spektrometrie MeSH
• fosforylace MeSH
• kinetika MeSH
• klonování DNA MeSH
• konzervovaná sekvence MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• myši MeSH
• proteiny 14-3-3 metabolismus   MeSH
• rekombinantní proteiny chemie   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• sekvenční seřazení MeSH
• transkripční faktory chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

Although electrical muscle stimulation (EMS) of skeletal muscle effectively prevents muscle atrophy, its effect on the breakdown of muscle component proteins is unknown. In this study, we investigated the biological mechanisms by which EMS-induced muscle contraction inhibits disuse muscle atrophy progression. Experimental animals were divided into a control group and three experimental groups: immobilized (Im; immobilization treatment), low-frequency (LF; immobilization treatment and low-frequency muscle contraction exercise), and high-frequency (HF; immobilization treatment and high-frequency muscle contraction exercise). Following the experimental period, bilateral soleus muscles were collected and analyzed. Atrogin-1 and Muscle RING finger 1 (MuRF-1) mRNA expression levels were significantly higher for the experimental groups than for the control group but were significantly lower for the HF group than for the Im group. Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) mRNA and protein expression levels in the HF group were significantly higher than those in the Im group, with no significant differences compared to the Con group. Both the Forkhead box O (FoxO)/phosphorylated FoxO and protein kinase B (AKT)/phosphorylated AKT ratios were significantly lower for the Im group than for the control group and significantly higher for the HF group than for the Im group. These results, the suppression of atrogin-1 and MuRF-1 expression for the HF group may be due to decreased nuclear expression of FoxO by AKT phosphorylation and suppression of FoxO transcriptional activity by PGC-1alpha. Furthermore, the number of muscle contractions might be important for effective EMS.

• MeSH
• kosterní svaly metabolismus   MeSH
• messenger RNA metabolismus   MeSH
• PPAR gama metabolismus   MeSH
• PPARGC1A metabolismus   MeSH
• protoonkogenní proteiny c-akt * metabolismus   MeSH
• svalová atrofie prevence a kontrola   genetika   metabolismus   MeSH
• svalové proteiny metabolismus   MeSH
• transkripční faktory * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

FOXO transcription factors are critical regulators of cell homeostasis and steer cell death, differentiation and longevity in mammalian cells. By combined pharmacophore-modeling-based in silico and fluorescence polarization-based screening we identified small molecules that physically interact with the DNA-binding domain (DBD) of FOXO3 and modulate the FOXO3 transcriptional program in human cells. The mode of interaction between compounds and the FOXO3-DBD was assessed via NMR spectroscopy and docking studies. We demonstrate that compounds S9 and its oxalate salt S9OX interfere with FOXO3 target promoter binding, gene transcription and modulate the physiologic program activated by FOXO3 in cancer cells. These small molecules prove the druggability of the FOXO-DBD and provide a structural basis for modulating these important homeostasis regulators in normal and malignant cells.

• MeSH
• DNA chemie   genetika   metabolismus   MeSH
• genetická transkripce účinky léků   MeSH
• genový knockdown MeSH
• HEK293 buňky MeSH
• knihovny malých molekul chemie   metabolismus   farmakologie   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární modely MeSH
• nádorové buněčné linie MeSH
• promotorové oblasti (genetika) genetika   MeSH
• protein FOXO3 chemie   genetika   metabolismus   MeSH
• proteinové domény MeSH
• simulace molekulového dockingu MeSH
• stanovení celkové genové exprese metody   MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH