http://bioinformatics.oxfordjournals.org – Interferon-β induced JAK-STAT signaling pathways contribute to mucosal immune recognition and an anti-viral state. Though the main molecular mechanisms constituting these pathways are known, neither the detailed structure of the regulatory network, nor its dynamics has yet been investigated. Read more »

http://www.pubmedcentral.nih.gov – The nuclear pore supports molecular communication between cytoplasm and nucleus in eukaryotic cells. Selective transport of proteins is mediated by soluble receptors, whose regulation by the small GTPase Ran leads to cargo accumulation in, or depletion from, the nucleus, i.e., nuclear import or nuclear export. We consider the operation of this transport system by a combined analytical and experimental approach. Provocative predictions of a simple model were tested using cell-free nuclei reconstituted in Xenopus egg extract, a system Read more »

http://www.ploscompbiol.org – The nuclear pore complex (NPC) is the gate to the nucleus. Recent determination of the configuration of proteins in the yeast NPC at ~5 nm resolution permits us to study the NPC global dynamics using coarse-grained structural models. We investigate these large-scale motions by using an extended elastic network model (ENM) formalism applied to several coarse-grained representations of the NPC. Two types of collective motions (global modes) are predicted by the ENMs to be intrinsically favored by the NPC architecture: global bending and extension/contraction from circular to elliptical shapes. Read more »

http://www.sciencemag.org – The nuclear pore complex regulates cargo transport between the cytoplasm and the nucleus. We set out to correlate the governing biochemical interactions to the nanoscopic responses of the phenylalanineglycine (FG)–rich nucleoporin domains, which are involved in attenuating or promoting cargo translocation. We found that binding interactions with the transport receptor karyopherin-b1 caused the FG domains of the human nucleoporin Nup153 to collapse into compact molecular conformations. Read more »

http://www.fasebj.org – Lipid signaling involved in mechanotransduction processes in response to shear stress in plants remained elusive. To understand the responses of phospholipids in shear stress-induced mechanotransduction, a lipidomic approach was employed to profile phospholipid species of Taxus cuspidata cells under laminar shear stress. A total of 99 phospholipid species were profiled quantitatively, using the LC/ESI/MSn procedure. Potential biomarkers were found by the principal component analysis (PCA) as well as partial least squares (PLS) combined with variable influence in the projection (VIP). Read more »

http://www.sciencemag.org – Transport of macromolecules between the nucleus and cytoplasm is a critical cellular process for eukaryotes, and the machinery that mediates nucleocytoplasmic exchange is subject to multiple levels of control. Regulation is achieved by modulating the expression or function of single cargoes, transport receptors, or the transport channel. Each of these mechanisms has increasingly broad impacts on transport patterns and capacity, and this hierarchy of control directly affects gene expression, signal transduction, development, and disease. Read more »

http://www.fasebj.org – Analysis of cellular mechanotransduc- tion, the mechanism by which cells convert mechanical signals into biochemical responses, has focused on identification of critical mechanosensitive molecules and cellular components. Stretch-activated ion chan- nels, caveolae, integrins, cadherins, growth factor re- ceptors, myosin motors, cytoskeletal filaments, nuclei, extracellular matrix, and numerous other structures and signaling molecules have all been shown to contrib- ute to the mechanotransduction response. Read more »

http://www.ncbi.nlm.nih.gov – In a variety of situations in living organisms, cells interact with their environment by generating traction forces. For example, muscle contractility (cardiac, skeletal and smooth muscles), ECs and permeability, stem cell differentiation might correlate with contractility (maybe…Engler). There are currently few methods by which one can measure the traction forces in a quantitative way, especially on the single-cell level; the most common method by which to study cells in vitro has been to use a polystyrene dish. Read more »

Mechanical stresses were applied directly to cell surface receptors with a magnetic twisting device. The extracellular matrix receptor, integrin beta 1, induced focal adhesion formation and supported a force-dependent stiffening response, whereas nonadhesion receptors did not. The cytoskeletal stiffness (ratio of stress to strain) increased in direct proportion to the applied stress and required intact microtubules and intermediate filaments as well as microfilaments. Read more »

http://physrev.physiology.org – The simplest cell-like structure, the lipid bilayer vesicle, can respond to mechanical deformation by elastic membrane dilation/thinning and curvature changes. When a protein is inserted in the lipid bilayer, an energetic cost may arise because of hydrophobic mismatch between the protein and bilayer. Localized changes in bilayer thickness and curvature may compensate for this mismatch. The peptides alamethicin and gramicidin and the bacterial membrane protein MscL form mechanically gated (MG) channels when inserted in lipid bilayers. Read more »