Modeling cancer genomic data in yeast reveals selection against ATM function during tumorigenesis

The DNA damage response (DDR) comprises multiple functions that collectively preserve genomic integrity and suppress tumorigenesis. The Mre11 complex and ATM govern a major axis of the DDR and several lines of evidence implicate that axis in tumor suppression. Components of the Mre11 complex are mutated in approximately five percent of human cancers. Inherited mutations of complex members cause severe chromosome instability syndromes, such as Nijmegen Breakage Syndrome, which is associated with strong predisposition to malignancy. And in mice, Mre11 complex mutations are markedly more susceptible to oncogene- induced carcinogenesis. The complex is integral to all modes of DNA double strand break (DSB) repair and is required for the activation of ATM to effect DNA damage signaling. To understand which functions of the Mre11 complex are important for tumor suppression, we undertook mining of cancer genomic data from the clinical sequencing program at Memorial Sloan Kettering Cancer Center, which includes the Mre11 complex among the 468 genes assessed. Twenty five mutations in MRE11 and RAD50 were modeled in S. cerevisiae and in vitro. The mutations were chosen based on recurrence and conservation between human and yeast. We found that a significant fraction of tumor-borne RAD50 and MRE11 mutations exhibited separation of function phenotypes wherein Tel1/ATM activation was severely impaired while DNA repair functions were mildly or not affected. At the molecular level, the gene products of RAD50 mutations exhibited defects in ATP binding and hydrolysis. The data reflect the importance of Rad50 ATPase activity for Tel1/ATM activation and suggest that inactivation of ATM signaling confers an advantage to burgeoning tumor cells

The N-Terminal domain of SIRT1 is a positive regulator of endogenous SIRT1-dependent deacetylation and transcriptional outputs

SummaryThe NAD+-dependent protein deacetylase SIRT1 regulates energy metabolism, responses to stress, and aging by deacetylating many different proteins, including histones and transcription factors. The mechanisms controlling SIRT1 enzymatic activity are complex and incompletely characterized, yet essential for understanding how to develop therapeutics that target SIRT1. Here, we demonstrate that the N-terminal domain of SIRT1 (NTERM) can trans-activate deacetylation activity by physically interacting with endogenous SIRT1 and promoting its association with the deacetylation substrate NF-κB p65. Two motifs within the NTERM domain contribute to activation of SIRT1-dependent activities, and expression of one of these motifs in mice is sufficient to lower fasting glucose levels and improve glucose tolerance in a manner similar to overexpression of SIRT1. Our results provide insights into the regulation of SIRT1 activity and a rationale for pharmacological control of SIRT1-dependent activities

Activation of SIRT1 by an N-terminal Regulatory Domain

The NAD+-dependent protein deacetylase SIRT1 regulates transcriptional responses and enzymatic functions involving energy metabolism, responses to stress, and aging and is thus a candidate drug target for the treatment of metabolic, inflammatory, and neurodegenerative diseases. However, the mechanism(s) controlling the activity of SIRT1 itself is poorly understood. SIRT1 overexpression or activation by small molecules has been shown to ameliorate disease phenotypes in both animal and cellular models of disease, making SIRT1 a high priority drug target. SIRT1 deacetylates many protein substrates including p53, HNF1- α , PPAR-γ , FOXO, NFκB, and Ku 70. The mechanism for selecting protein substrates is enigmatic since there is no defined sequence motif surrounding the acetyl-lysine targeted for deacetylation, and a variety of peptide substrates are accommodated in vitro. My thesis project aimed to understand how SIRT1 achieves its biological specialization for specific protein targets and cellular activities; specifically, the role of SIRT1\u27s unique N-terminal domain in selecting substrates and activating SIRT1 enzymatic activity. We have shown that the recombinant N-terminal (NTERM) domain (SIRT1 residues 1-221) trans-activates deacetylation activity, revealing an unprecedented mechanism for the regulation of SIRT1 activity. The NTERM domain physically interacts with endogenous SIRT1 and promotes its association with protein substrates including the p65 subunit of NF-κB. Two motifs within the NTERM domain contribute to activation of SIRT1-dependent activities, and one of these motifs is targeted by the negative regulator, Deleted in Breast Cancer 1 (DBC1). These novel bipartite motifs interact with each other, and thus may function in cis to enhance substrate binding or allosterically control SIRT1 enzymatic activity. Our results provide a new rationale for the selective pharmacological control of SIRT1-dependent activities

Supertek plant redistribution through SLP

Este proyecto se realizó en la empresa Supertek S.A.S, perteneciente al sector metalmecánico, la cual se encarga de fabricar estructuras y accesorios metálicos necesarios para la construcción de otros productos. Esta empresa se trasladó a unas nuevas instalaciones con un área de 2359.36 m2, sin previamente haber dispuesto cual iba a ser el mejor ordenamiento y manejo de las áreas de trabajo en su proceso productivo. Esto para cualquier instalación es uno de los aspectos clave para generar un correcto funcionamiento operacional y una mayor productividad. El objetivo principal de este proyecto fue diseñar un layout de la planta para minimizar tiempos y desplazamientos entre procesos de manufactura mediante la metodología SLP (Systematic Layout Planning), y teniendo en cuenta el proceso de fabricación de la estructura mediana (Soporte Base Secadora ST-20AX). El SLP involucra varios pasos que mediante el análisis de las relaciones de criterio cualitativo entre zonas de trabajo, y la visualización de todos los componentes concurrentes en el proceso productivo, dan como resultado diversas alternativas de distribución de espacios. Las alternativas resultantes fueron sometidas a un análisis de factores ponderados, y la disposición final fue validada mediante estadísticas arrojadas por un modelo de simulación realizado en Arena Simulation Software. Los resultados finales de nuestra propuesta muestran que los tiempos totales de fabricación promedio se disminuyeron en un 8%, pasando de 35.54 a 32.61 horas con la nueva distribución. Igualmente, se redujeron el número de transportes a realizar en un 1% aproximadamente. Finalmente, con el nuevo layout se ahorró un 6% del espacio total utilizado.This project was carried out in Supertek S.A.S, a manufacturing company from the metal-mechanic sector; the company is responsible for manufacturing structures and metal accessories necessary to manufacture other products. This company moved to a new facility with an area of 2359.36 m2, without having previously established what would be the best arrangement and management of work areas in its production process. This for any installation is one of the key aspects to generate a correct operational performance and higher productivity. The main objective of this project was to design a plant layout to minimize time and transports between manufacturing processes using the SLP (Systematic Layout Planning) methodology and considering the manufacturing process of a medium structure (Base Dryer Support ST- 20AX). The SLP involves several steps that, by analyzing the relationships of qualitative criteria between work areas, and the visualization of all the concurrent components in the production process, resulting in various alternatives for space distribution. The resulting alternatives were subjected to an analysis of weighted factors, and the final disposition was validated through statistics produced by a simulation model carried out in Arena Simulation Software. The final results of our proposal reveals that the total average manufacturing times decreased by 8%, going from 35.54 to 32.61 hours with the new distribution. Likewise, the number of transports between processes was reduced by approximately 1%. Finally, with the new layout, 6% of the total space used was released

Internal and External Mycoflora of the American Dog Tick, Dermacentor variabilis (Acari: Ixodidae), and Its Ecological Implications

Scopulariopsis brevicaulis, the anamorph of Microascus brevicaulis (Microascaceae, Ascomycota), has been identified in the body contents of the tick Dermacentor variabilis. After topical application of the fungal inoculum, tick mortality was marked. This is the first account describing the internal mycoflora of D. variabilis with a novel technique used to recover potential biological control agents