ARF is a small, highly basic protein that can be induced by oncogenic stimuli and exerts growth-inhibitory and tumour-suppressive activities through the activation of p53. Here we show that, in human melanocytes, ARF is cytoplasmic, constitutively expressed, and required for maintaining low steady-state levels of superoxide under conditions of mitochondrial dysfunction. This mitochondrial activity of ARF is independent of its known autophagic and p53-dependent functions, and involves the evolutionarily conserved acidic motif GHDDGQ, which exhibits weak homology to BCL-2 homology 3 (BH3) domains and mediates interaction with BCL-xL--an important regulator of mitochondrial redox homeostasis. Melanoma-predisposing CDKN2A germline mutations, which affect conserved glycine and aspartate residues within the GHDDGQ motif, impair the ability of ARF to control superoxide production and suppress growth of melanoma cells in vivo. These results reveal an important cell-protective function of ARF that links mitochondrial dysfunction and susceptibility to melanoma.

• MeSH
• aminokyselinové motivy MeSH
• buněčné dýchání MeSH
• genetická predispozice k nemoci MeSH
• kultivované buňky MeSH
• lidé MeSH
• melanocyty metabolismus   MeSH
• melanom genetika   MeSH
• mitochondriální nemoci metabolismus   MeSH
• nádorový supresorový protein p14ARF metabolismus   MeSH
• protein bcl-X metabolismus   MeSH
• superoxidy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BCL2L1 protein, human MeSH Prohlížeč
• nádorový supresorový protein p14ARF MeSH
• protein bcl-X MeSH
• superoxidy MeSH

Cell growth requires a high level of protein synthesis and oncogenic pathways stimulate cell proliferation and ribosome biogenesis. Less is known about how cells respond to dysfunctional mRNA translation and how this feeds back into growth regulatory pathways. The Epstein-Barr virus (EBV)-encoded EBNA1 causes mRNA translation stress in cis that activates PI3Kδ. This leads to the stabilization of MDM2, induces MDM2's binding to the E2F1 mRNA and promotes E2F1 translation. The MDM2 serine 166 regulates the interaction with the E2F1 mRNA and deletion of MDM2 C-terminal RING domain results in a constitutive E2F1 mRNA binding. Phosphorylation on serine 395 following DNA damage instead regulates p53 mRNA binding to its RING domain and prevents the E2F1 mRNA interaction. The p14Arf tumour suppressor binds MDM2 and in addition to preventing degradation of the p53 protein it also prevents the E2F1 mRNA interaction. The data illustrate how two MDM2 domains selectively bind specific mRNAs in response to cellular conditions to promote, or suppress, cell growth and how p14Arf coordinates MDM2's activity towards p53 and E2F1. The data also show how EBV via EBNA1-induced mRNA translation stress targets the E2F1 and the MDM2 - p53 pathway.

• MeSH
• buněčný cyklus genetika   MeSH
• fosforylace genetika   MeSH
• karcinogeneze genetika   MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• nádorový supresorový protein p14ARF genetika   MeSH
• nádorový supresorový protein p53 genetika   MeSH
• nádory genetika   virologie   MeSH
• onkogeny genetika   MeSH
• poškození DNA genetika   MeSH
• proliferace buněk genetika   MeSH
• proteinové domény genetika   MeSH
• protoonkogenní proteiny c-mdm2 genetika   MeSH
• RRM proteiny genetika   MeSH
• transkripční faktor E2F1 genetika   MeSH
• tumor supresorové geny MeSH
• virus Epsteinův-Barrové genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• E2F1 protein, human MeSH Prohlížeč
• MDM2 protein, human MeSH Prohlížeč
• messenger RNA MeSH
• nádorový supresorový protein p14ARF MeSH
• nádorový supresorový protein p53 MeSH
• protoonkogenní proteiny c-mdm2 MeSH
• RRM proteiny MeSH
• TP53 protein, human MeSH Prohlížeč
• transkripční faktor E2F1 MeSH

Repetitive sequences are among the most unstable regions in the eukaryotic genome and defects in their maintenance correlate with premature aging and cancer development. Promyelocytic leukemia protein (PML) induces accumulation of proteins at distinct nuclear sites, thereby affecting a plethora of processes including DNA repair or maintenance of telomeres. Doxorubicin, the broadly used chemotherapeutic compound, induces formation of PML-nucleolar associations (PNAs). Nevertheless, molecular factors affecting formation of PNAs are still largely unknown. Here we show that PNAs can accumulate ribosomal DNA (rDNA) and, after restoration of RNA polymerase I activity, these structures transfer a fraction of rDNA outside the nucleolus. Mutagenesis of PML isoforms revealed that this process depends on the SUMO-interacting motif and adjacent serine-rich region, and is enhanced by exon8b present exclusively in PML IV isoform. Moreover, we demonstrate that PNAs formation is also regulated by p14ARF/p53 tumor suppressors and casein kinase 2. Our data elucidate how PML nucleolar compartment is assembled, bring the first evidence of PML interacting with rDNA, and show the PML-dependent translocation of rDNA away from the nucleolus.

• Klíčová slova
• Nucleolus, P14(ARF), PML, Phospho-SIM, rDNA,
• MeSH
• doxorubicin farmakologie   MeSH
• jaderné proteiny * metabolismus   MeSH
• nádorové supresorové proteiny genetika   metabolismus   MeSH
• peptidové nukleové kyseliny * MeSH
• protein - isoformy metabolismus   MeSH
• ribozomální DNA genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• doxorubicin MeSH
• jaderné proteiny * MeSH
• nádorové supresorové proteiny MeSH
• peptidové nukleové kyseliny * MeSH
• protein - isoformy MeSH
• ribozomální DNA MeSH