HeLa Cells

Publication Title: 
The EMBO journal

The yeast Sir2 protein mediates chromatin silencing through an intrinsic NAD-dependent histone deacetylase activity. Sir2 is a conserved protein and was recently shown to regulate lifespan extension both in budding yeast and worms. Here, we show that SIRT1, the human Sir2 homolog, is recruited to the promyelocytic leukemia protein (PML) nuclear bodies of mammalian cells upon overexpression of either PML or oncogenic Ras (Ha-rasV12). SIRT1 binds and deacetylates p53, a component of PML nuclear bodies, and it can repress p53-mediated transactivation.

Author(s): 
Langley, Emma
Pearson, Mark
Faretta, Mario
Bauer, Uta-Maria
Frye, Roy A.
Minucci, Saverio
Pelicci, Pier Giuseppe
Kouzarides, Tony
Publication Title: 
The Journal of Biological Chemistry

In lower organisms, increased expression of the NAD-dependent deacetylase Sir2 augments lifespan. The mechanism through which this life extension is mediated remains incompletely understood. Here we have examined the cellular effects of overexpression of SIRT1, the closest mammalian ortholog of Sir2. In PC12 cells, increased expression of the NAD-dependent deacetylase SIRT1 reduces cellular oxygen consumption by approximately 25%. We further demonstrate that SIRT1 expression can alter the transcriptional activity of the mitochondrial biogenesis coactivator PGC-1alpha.

Author(s): 
Nemoto, Shino
Fergusson, Maria M.
Finkel, Toren
Publication Title: 
Molecular Biology and Evolution

Insertions or deletions (indels) of amino acids residues have been recognized as an important source of genetic and structural divergence between paralogous Bcl-2 family members. However, these signature sequences have not so far been extensively investigated amongst orthologous Bcl-2 family proteins. Bcl2l10 is an antiapoptotic member of the Bcl-2 family that has evolved rapidly throughout the vertebrate lineage and which shows conserved abundant expression in eggs and oocytes.

Author(s): 
Guillemin, Yannis
Cornut-Thibaut, AurÈlie
Gillet, Germain
Penin, FranÁois
Aouacheria, Abdel
Publication Title: 
Open Biology

Multi-cellular organisms need to successfully link cell growth and metabolism to environmental cues during development. Insulin receptor-target of rapamycin (InR-TOR) signalling is a highly conserved pathway that mediates this link. Herein, we describe poly, an essential gene in Drosophila that mediates InR-TOR signalling. Loss of poly results in lethality at the third instar larval stage, but only after a stage of extreme larval longevity.

Author(s): 
Bolukbasi, Ekin
Vass, Sharron
Cobbe, Neville
Nelson, Bryce
Simossis, Victor
Dunbar, Donald R.
Heck, Margarete M. S.
Publication Title: 
Cell Death & Disease

Overexpression of Bcl-2 contributes to resistance of cancer cells to human cytotoxic lymphocytes (CL) by blocking granzyme B (GraB)-induced mitochondrial outer membrane permeabilization (MOMP). Drugs that neutralise Bcl-2 (e.g., ABT-737) may therefore be effective adjuvants for immunotherapeutic strategies that use CL to kill cancer cells. Consistent with this we found that ABT-737 effectively restored MOMP in Bcl-2 overexpressing cells treated with GraB or natural killer cells.

Author(s): 
Sutton, V. R.
Sedelies, K.
Dewson, G.
Christensen, M. E.
Bird, P. I.
Johnstone, R. W.
Kluck, R. M.
Trapani, J. A.
Waterhouse, N. J.
Publication Title: 
Molecular Cell

Cellular processes function through multistep pathways that are reliant on the controlled association and disassociation of sequential protein complexes. While dynamic action is critical to propagate and terminate work, the mechanisms used to disassemble biological structures are not fully understood. Here we show that the p23 molecular chaperone initiates disassembly of protein-DNA complexes and that the GCN5 acetyltransferase prolongs the dissociated state through lysine acetylation.

Author(s): 
Zelin, Elena
Zhang, Yang
Toogun, Oyetunji A.
Zhong, Sheng
Freeman, Brian C.
Publication Title: 
Molecular and Cellular Biology

SIRT3 is a member of the Sir2 family of NAD(+)-dependent protein deacetylases that promotes longevity in many organisms. The processed short form of SIRT3 is a well-established mitochondrial protein whose deacetylase activity regulates various metabolic processes. However, the presence of full-length (FL) SIRT3 in the nucleus and its functional importance remain controversial. Our previous studies demonstrated that nuclear FL SIRT3 functions as a histone deacetylase and is transcriptionally repressive when artificially recruited to a reporter gene.

Author(s): 
Iwahara, Toshinori
Bonasio, Roberto
Narendra, Varun
Reinberg, Danny
Publication Title: 
Molecular and Cellular Biology

The AU-rich elements (AREs) encoded within many mRNA 3' untranslated regions (3'UTRs) are targets for factors that control transcript longevity and translational efficiency. Hsp70, best known as a protein chaperone with well-defined peptide-refolding properties, is known to interact with ARE-like RNA substrates in vitro. Here, we show that cofactor-free preparations of Hsp70 form direct, high-affinity complexes with ARE substrates based on specific recognition of U-rich sequences by both the ATP- and peptide-binding domains.

Author(s): 
Kishor, Aparna
Tandukar, Bishal
Ly, Yann V.
Toth, Eric A.
Suarez, Yvelisse
Brewer, Gary
Wilson, Gerald M.
Publication Title: 
Genes & Development

Adaptation to nutrient scarcity depends on the activation of metabolic programs to efficiently use internal reserves of energy. Activation of these programs in abundant food regimens can extend life span. However, the common molecular and metabolic changes that promote adaptation to nutritional stress and extend life span are mostly unknown. Here we present a response to fasting, enrichment of ?-6 polyunsaturated fatty acids (PUFAs), which promotes starvation resistance and extends Caenorhabditis elegans life span. Upon fasting, C.

Author(s): 
O'Rourke, Eyleen J.
Kuballa, Petric
Xavier, Ramnik
Ruvkun, Gary
Publication Title: 
Journal of Neurochemistry

The human tyrosine hydroxylase (hTH) gene has a 42†bp evolutionarily conserved region designated (CR) II at -7.24†kb, which bears 93% homology to the region we earlier identified as containing the glucocorticoid response element, a 7†bp activator protein-1 (AP-1)-like motif in the rat TH gene. We cloned this hTH-CRII region upstream of minimal basal hTH promoter in luciferase (Luc) reporter vector, and tested glucocorticoid responsiveness in human cell lines.

Author(s): 
Sheela Rani, C. S.
Soto-Pina, Alexandra
Iacovitti, Lorraine
Strong, Randy

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