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Full-Text Articles in Life Sciences

Interactions Between Connected Half-Sarcomeres Produce Emergent Mechanical Behavior In A Mathematical Model Of Muscle, Kenneth S. Campbell Nov 2009

Interactions Between Connected Half-Sarcomeres Produce Emergent Mechanical Behavior In A Mathematical Model Of Muscle, Kenneth S. Campbell

Physiology Faculty Publications

Most reductionist theories of muscle attribute a fiber's mechanical properties to the scaled behavior of a single half-sarcomere. Mathematical models of this type can explain many of the known mechanical properties of muscle but have to incorporate a passive mechanical component that becomes approximately 300% stiffer in activating conditions to reproduce the force response elicited by stretching a fast mammalian muscle fiber. The available experimental data suggests that titin filaments, which are the mostly likely source of the passive component, become at most approximately 30% stiffer in saturating Ca2+ solutions. The work described in this manuscript used computer modeling to …


The Leishmania Donovani Lipophosphoglycan Excludes The Vesicular Proton-Atpase From Phagosomes By Impairing The Recruitment Of Synaptotagmin V, Adrien F. Vinet, Mitsunori Fukuda, Salvatore J. Turco, Albert Descoteaux Oct 2009

The Leishmania Donovani Lipophosphoglycan Excludes The Vesicular Proton-Atpase From Phagosomes By Impairing The Recruitment Of Synaptotagmin V, Adrien F. Vinet, Mitsunori Fukuda, Salvatore J. Turco, Albert Descoteaux

Molecular and Cellular Biochemistry Faculty Publications

We recently showed that the exocytosis regulator Synaptotagmin (Syt) V is recruited to the nascent phagosome and remains associated throughout the maturation process. In this study, we investigated the possibility that Syt V plays a role in regulating interactions between the phagosome and the endocytic organelles. Silencing of Syt V by RNA interference revealed that Syt V contributes to phagolysosome biogenesis by regulating the acquisition of cathepsin D and the vesicular proton-ATPase. In contrast, recruitment of cathepsin B, the early endosomal marker EEA1 and the lysosomal marker LAMP1 to phagosomes was normal in the absence of Syt V. As Leishmania …


Polyglutamine Disruption Of The Huntingtin Exon 1 N Terminus Triggers A Complex Aggregation Mechanism, Ashwani K. Thakur, Murali Jayaraman, Rakesh Mishra, Monika Thakur, Veronique M. Chellgren, In-Ja L Byeon, Dalaver H. Anjum, Ravindra Kodali, Trevor P. Creamer, James F. Conway, Angela M. Gronenborn, Ronald Wetzel Apr 2009

Polyglutamine Disruption Of The Huntingtin Exon 1 N Terminus Triggers A Complex Aggregation Mechanism, Ashwani K. Thakur, Murali Jayaraman, Rakesh Mishra, Monika Thakur, Veronique M. Chellgren, In-Ja L Byeon, Dalaver H. Anjum, Ravindra Kodali, Trevor P. Creamer, James F. Conway, Angela M. Gronenborn, Ronald Wetzel

Molecular and Cellular Biochemistry Faculty Publications

Simple polyglutamine (polyQ) peptides aggregate in vitro via a nucleated growth pathway directly yielding amyloid-like aggregates. We show here that the 17-amino-acid flanking sequence (HTTNT) N-terminal to the polyQ in the toxic huntingtin exon 1 fragment imparts onto this peptide a complex alternative aggregation mechanism. In isolation, the HTTNT peptide is a compact coil that resists aggregation. When polyQ is fused to this sequence, it induces in HTTNT, in a repeat-length dependent fashion, a more extended conformation that greatly enhances its aggregation into globular oligomers with HTTNT cores and exposed polyQ. In a second …


A Discontinuous Rna Platform Mediates Rna Virus Replication: Building An Integrated Model For Rna-Based Regulation Of Viral Processes, Baodong Wu, Judit Pogany, Hong Na, Beth L. Nicholson, Peter D. Nagy, K. Andrew White Mar 2009

A Discontinuous Rna Platform Mediates Rna Virus Replication: Building An Integrated Model For Rna-Based Regulation Of Viral Processes, Baodong Wu, Judit Pogany, Hong Na, Beth L. Nicholson, Peter D. Nagy, K. Andrew White

Plant Pathology Faculty Publications

Plus-strand RNA viruses contain RNA elements within their genomes that mediate a variety of fundamental viral processes. The traditional view of these elements is that of local RNA structures. This perspective, however, is changing due to increasing discoveries of functional viral RNA elements that are formed by long-range RNA-RNA interactions, often spanning thousands of nucleotides. The plus-strand RNA genomes of tombusviruses exemplify this concept by possessing different long-range RNA-RNA interactions that regulate both viral translation and transcription. Here we report that a third fundamental tombusvirus process, viral genome replication, requires a long-range RNA-based interaction spanning approximately 3000 nts. In vivo …