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Full-Text Articles in Medicine and Health Sciences

A Xenopus Oocyte Model System To Study Action Potentials, Aaron Corbin-Leftwich, Hannah E Small, Helen H Robinson, Carlos A. Villalba-Galea, Linda M Boland Nov 2018

A Xenopus Oocyte Model System To Study Action Potentials, Aaron Corbin-Leftwich, Hannah E Small, Helen H Robinson, Carlos A. Villalba-Galea, Linda M Boland

School of Pharmacy Faculty Articles

Action potentials (APs) are the functional units of fast electrical signaling in excitable cells. The upstroke and downstroke of an AP is generated by the competing and asynchronous action of Na+- and K+-selective voltage-gated conductances. Although a mixture of voltage-gated channels has been long recognized to contribute to the generation and temporal characteristics of the AP, understanding how each of these proteins function and are regulated during electrical signaling remains the subject of intense research. AP properties vary among different cellular types because of the expression diversity, subcellular location, and modulation of ion channels. These complexities, in addition to the …


Hdac8 And Stat3 Repress Bmf Gene Activity In Colon Cancer Cells, Y Kang, Hui Nian, P Rajendran, W Dashwood, John T. Pinto, E Ho, R Dashwood Oct 2014

Hdac8 And Stat3 Repress Bmf Gene Activity In Colon Cancer Cells, Y Kang, Hui Nian, P Rajendran, W Dashwood, John T. Pinto, E Ho, R Dashwood

NYMC Faculty Publications

Histone deacetylase (HDAC) inhibitors are undergoing clinical trials as anticancer agents, but some exhibit resistance mechanisms linked to anti-apoptotic Bcl-2 functions, such as BH3-only protein silencing. HDAC inhibitors that reactivate BH3-only family members might offer an improved therapeutic approach. We show here that a novel seleno-α-keto acid triggers global histone acetylation in human colon cancer cells and activates apoptosis in a p21-independent manner. Profiling of multiple survival factors identified a critical role for the BH3-only member Bcl-2-modifying factor (Bmf). On the corresponding BMF gene promoter, loss of HDAC8 was associated with signal transducer and activator of transcription 3 (STAT3)/specificity protein …


Structural And Biophysical Characterization Of Staphylococcus Aureus Samazf Shows Conservation Of Functional Dynamics, Valentina Zorzini, Lieven Buts, Mike Sleutel, Abel Garcia-Pino, Ariel Talavera, Sarah Haesaerts, Henri De Greve, Ambrose Cheung, Nico A. J. Van Nuland, Remy Loris Mar 2014

Structural And Biophysical Characterization Of Staphylococcus Aureus Samazf Shows Conservation Of Functional Dynamics, Valentina Zorzini, Lieven Buts, Mike Sleutel, Abel Garcia-Pino, Ariel Talavera, Sarah Haesaerts, Henri De Greve, Ambrose Cheung, Nico A. J. Van Nuland, Remy Loris

Dartmouth Scholarship

The Staphylococcus aureus genome contains three toxin-antitoxin modules, including one mazEF module, SamazEF. Using an on-column separation protocol we are able to obtain large amounts of wild-type SaMazF toxin. The protein is well-folded and highly resistant against thermal unfolding but aggregates at elevated temperatures. Crystallographic and nuclear magnetic resonance (NMR) solution studies show a well-defined dimer. Differences in structure and dynamics between the X-ray and NMR structural ensembles are found in three loop regions, two of which undergo motions that are of functional relevance. The same segments also show functionally relevant dynamics in the distantly related CcdB family despite divergence …


The Gating Charge Should Not Be Estimated By Fitting A Two-State Model To A Q-V Curve, Francisco Bezanilla, Carlos A. Villalba-Galea Dec 2013

The Gating Charge Should Not Be Estimated By Fitting A Two-State Model To A Q-V Curve, Francisco Bezanilla, Carlos A. Villalba-Galea

School of Pharmacy Faculty Articles

The voltage dependence of charges in voltage-sensitive proteins, typically displayed as charge versus voltage (Q-V) curves, is often quantified by fitting it to a simple two-state Boltzmann function. This procedure overlooks the fact that the fitted parameters, including the total charge, may be incorrect if the charge is moving in multiple steps. We present here the derivation of a general formulation for Q-V curves from multistate sequential models, including the case of infinite number of states. We demonstrate that the commonly used method to estimate the charge per molecule using a simple Boltzmann fit is not only inadequate, but in …


Sensing Charges Of The Ciona Intestinalis Voltage-Sensing Phosphatase, Carlos A. Villalba-Galea, Ludivine Frezza, Walter Sandtner, Francisco Bezanilla Nov 2013

Sensing Charges Of The Ciona Intestinalis Voltage-Sensing Phosphatase, Carlos A. Villalba-Galea, Ludivine Frezza, Walter Sandtner, Francisco Bezanilla

School of Pharmacy Faculty Articles

Voltage control over enzymatic activity in voltage-sensitive phosphatases (VSPs) is conferred by a voltage-sensing domain (VSD) located in the N terminus. These VSDs are constituted by four putative transmembrane segments (S1 to S4) resembling those found in voltage-gated ion channels. The putative fourth segment (S4) of the VSD contains positive residues that likely function as voltage-sensing elements. To study in detail how these residues sense the plasma membrane potential, we have focused on five arginines in the S4 segment of the Ciona intestinalis VSP (Ci-VSP). After implementing a histidine scan, here we show that four arginine-to-histidine mutants, namely R223H to …


Local Tobacco Control: Application Of The Essential Public Health Services Model In A County Health Department’S Efforts To Put It Out Rockland, Lisa D. Lieberman, Una Diffley, Sandy King, Shelley Chanler, Maryanne Ferrera, Oscar Alleyne, Joan Facelle Nov 2013

Local Tobacco Control: Application Of The Essential Public Health Services Model In A County Health Department’S Efforts To Put It Out Rockland, Lisa D. Lieberman, Una Diffley, Sandy King, Shelley Chanler, Maryanne Ferrera, Oscar Alleyne, Joan Facelle

Department of Public Health Scholarship and Creative Works

In 2000, Rockland County, a small suburban county north of New York City, dedicated $1 million of its Master Settlement Agreement funds to a comprehensive tobacco control program, Put It Out Rockland. Developed and implemented by the county health department, this program used an essential public health services model and an ongoing financial investment, within the context of strong statewide tobacco control efforts, to lower adult smoking rates to 9.7% and to reduce both smoking among youths and exposure to secondhand smoke over the ensuing decade. By combining state funds and local dollars for a total of $6.75 cost per …


A Survey Of Oxidative Paracatalytic Reactions Catalyzed By Enzymes That Generate Carbanionic Intermediates: Implications For Ros Production, Cancer Etiology, And Neurodegenerative Diseases, Victoria Bunik, John Schloss, John T. Pinto, Natalia Dudareva, Arthur J L Cooper Feb 2011

A Survey Of Oxidative Paracatalytic Reactions Catalyzed By Enzymes That Generate Carbanionic Intermediates: Implications For Ros Production, Cancer Etiology, And Neurodegenerative Diseases, Victoria Bunik, John Schloss, John T. Pinto, Natalia Dudareva, Arthur J L Cooper

NYMC Faculty Publications

Enzymes that generate carbanionic intermediates often catalyze paracatalytic reactions with O2 and other electrophiles not considered “normal” reactants. For example, pyridoxal 5′-phosphate (PLP)—containing pig kidney dopa decarboxylase oxidizes dopamine with molecular O2 to 3,4-dihydroxyphenylacetaldehyde at about 1% of the rate at which it catalyzes nonoxidative dopa decarboxylation. The mutant Y332F enzyme, however, catalyzes stoichiometric conversion of dopa to 3,4-dihydroxyphenylacetaldehyde, suggesting that even minor structural changes may alter or initiate paracatalytic reactions catalyzed by certain enzymes. Carbanions generated by several thiamine diphosphate (ThDP)—dependent enzymes react with different electrophiles, transforming some xenobiotics and endogenous compounds into potentially biologically hazardous products. The detrimental …


Differential Impact Of Tumor Suppressor Pathways On Dna Damage Response And Therapy-Induced Transformation In A Mouse Primary Cell Model., A Kathleen Mcclendon, Jeffry L Dean, Adam Ertel, Erik S Knudsen Jan 2010

Differential Impact Of Tumor Suppressor Pathways On Dna Damage Response And Therapy-Induced Transformation In A Mouse Primary Cell Model., A Kathleen Mcclendon, Jeffry L Dean, Adam Ertel, Erik S Knudsen

Department of Cancer Biology Faculty Papers

The RB and p53 tumor suppressors are mediators of DNA damage response, and compound inactivation of RB and p53 is a common occurrence in human cancers. Surprisingly, their cooperation in DNA damage signaling in relation to tumorigenesis and therapeutic response remains enigmatic. In the context of individuals with heritable retinoblastoma, there is a predilection for secondary tumor development, which has been associated with the use of radiation-therapy to treat the primary tumor. Furthermore, while germline mutations of the p53 gene are critical drivers for cancer predisposition syndromes, it is postulated that extrinsic stresses play a major role in promoting varying …