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Medical Biochemistry Commons

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Full-Text Articles in Medical Biochemistry

Eisosomes Provide Membrane Reservoirs For Rapid Expansion Of The Yeast Plasma Membrane, Ruth Kabeche, Louisa Howard, James B. Moseley Sep 2015

Eisosomes Provide Membrane Reservoirs For Rapid Expansion Of The Yeast Plasma Membrane, Ruth Kabeche, Louisa Howard, James B. Moseley

Dartmouth Scholarship

Cell surface area rapidly increases during mechanical and hypoosmotic stresses. Such expansion of the plasma membrane requires 'membrane reservoirs' that provide surface area and buffer membrane tension, but the sources of this membrane remain poorly understood. In principle, the flattening of invaginations and buds within the plasma membrane could provide this additional surface area, as recently shown for caveolae in animal cells. Here, we used microfluidics to study the rapid expansion of the yeast plasma membrane in protoplasts, which lack the rigid cell wall. To survive hypoosmotic stress, yeast cell protoplasts required eisosomes, protein-based structures that generate long invaginations at …


A Structural And Functional Comparison Between Infectious And Non-Infectious Autocatalytic Recombinant Prp Conformers, Geoffrey P. Noble, Daphne W. Wang, Daniel J. Walsh, Justin R. Barone, Michael B. Miller, Koren A. Nishina, Sheng Li, Surachai Supattapone Jun 2015

A Structural And Functional Comparison Between Infectious And Non-Infectious Autocatalytic Recombinant Prp Conformers, Geoffrey P. Noble, Daphne W. Wang, Daniel J. Walsh, Justin R. Barone, Michael B. Miller, Koren A. Nishina, Sheng Li, Surachai Supattapone

Dartmouth Scholarship

Infectious prions contain a self-propagating, misfolded conformer of the prion protein termed PrPSc. A critical prediction of the protein-only hypothesis is that autocatalytic PrPSc molecules should be infectious. However, some autocatalytic recombinant PrPSc molecules have low or undetectable levels of specific infectivity in bioassays, and the essential determinants of recombinant prion infectivity remain obscure. To identify structural and functional features specifically associated with infectivity, we compared the properties of two autocatalytic recombinant PrP conformers derived from the same original template, which differ by >105-fold in specific infectivity for wild-type mice. Structurally, hydrogen/deuterium exchange mass spectrometry (DXMS) studies revealed that solvent …


A Novel Caspase 8 Selective Small Molecule Potentiates Trail-Induced Cell Death, Octavian Bucur, Gabriel Gaidos, Achani Yatawara, Bodvael Pennarun, Chamila Rupasinghe, Jérémie Roux, Stefan Andrei, Bingqian Guo, Alexandra Panaitiu, Maria Pellegrini, Dale Mierke, Roya Khosravi-Far May 2015

A Novel Caspase 8 Selective Small Molecule Potentiates Trail-Induced Cell Death, Octavian Bucur, Gabriel Gaidos, Achani Yatawara, Bodvael Pennarun, Chamila Rupasinghe, Jérémie Roux, Stefan Andrei, Bingqian Guo, Alexandra Panaitiu, Maria Pellegrini, Dale Mierke, Roya Khosravi-Far

Dartmouth Scholarship

Recombinant soluble TRAIL and agonistic antibodies against TRAIL receptors (DR4 and DR5) are currently being created for clinical cancer therapy, due to their selective killing of cancer cells and high safety characteristics. However, resistance to TRAIL and other targeted therapies is an important issue facing current cancer research field. An attractive strategy to sensitize resistant malignancies to TRAIL-induced cell death is the design of small molecules that target and promote caspase 8 activation. For the first time, we describe the discovery and characterization of a small molecule that directly binds caspase 8 and enhances its activation when combined with TRAIL, …


Sec17 Can Trigger Fusion Of Trans-Snare Paired Membranes Without Sec18, Michael Zick, Amy Orr, Matthew L. Schwartz, Alexey J. Merz, William Wickner Apr 2015

Sec17 Can Trigger Fusion Of Trans-Snare Paired Membranes Without Sec18, Michael Zick, Amy Orr, Matthew L. Schwartz, Alexey J. Merz, William Wickner

Dartmouth Scholarship

Sec17 [soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein; α-SNAP] and Sec18 (NSF) perform ATP-dependent disassembly of cis-SNARE complexes, liberating SNAREs for subsequent assembly of trans-complexes for fusion. A mutant of Sec17, with limited ability to stimulate Sec18, still strongly enhanced fusion when ample Sec18 was supplied, suggesting that Sec17 has additional functions. We used fusion reactions where the four SNAREs were initially separate, thus requiring no disassembly by Sec18. With proteoliposomes bearing asymmetrically disposed SNAREs, tethering and trans-SNARE pairing allowed slow fusion. Addition of Sec17 did not affect the levels of trans-SNARE complex but triggered sudden fusion of trans-SNARE paired proteoliposomes. …


Fungal Mediator Tail Subunits Contain Classical Transcriptional Activation Domains, Zhongle Liu, Lawrence C. Myers Feb 2015

Fungal Mediator Tail Subunits Contain Classical Transcriptional Activation Domains, Zhongle Liu, Lawrence C. Myers

Dartmouth Scholarship

Classical activation domains within DNA-bound eukaryotic transcription factors make weak interactions with coactivator complexes, such as Mediator, to stimulate transcription. How these interactions stimulate transcription, however, is unknown. The activation of reporter genes by artificial fusion of Mediator subunits to DNA binding domains that bind to their promoters has been cited as evidence that the primary role of activators is simply to recruit Mediator. We have identified potent classical transcriptional activation domains in the C termini of several tail module subunits of Saccharomyces cerevisiae, Candida albicans, and Candida dubliniensis Mediator, while their N-terminal domains are necessary and sufficient for their …