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Institut für Physiologie und Pathophysiologie

Single Molecules

Figure 1: Schematic experimental set-up: actin filaments move over a surface of myosin or heavy meromyosin
Figure 2: Movement of fluorescently labeled actin filaments recorded with a highly sensitive CCD camera

Molecular dynamics in the in vitro motility assay

The ability of heart and skeletal muscle to contract is based on the fundamental interaction of the two contractile proteins actin and myosin. This basic interaction can be studied in the in vitro motility assay originally devised by Kron and Spudich (1986), where fluorescently labeled actin filaments move over a surface of immobilised myosin or heavy meromyosin. The motion of actin filaments is recorded with a highly sensitive fluorescence imaging set-up.

 

Many parameters of this motion have been shown to be of significant importance for our understanding of the acto-myosin interaction, as e.g. the filament velocity is thought to be directly correlated to the unloaded shortening velocity of muscle fibers and therefore a direct reflection of the cross-bridge turnover rate. Also this assay is ideally suited to screen the functional domains of myosin, such as the nucleotide binding site, the actin binding site, the converter region and the lever arm. Furthermore myosin isoforms and actin mutants can be selectively studied in this assay.

 

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Force measurements with optical tweezers

Optical tweezers is the name of a technique for holding small objects such as polystyrene beads in the focus of a laser beam. The diffraction of the laser at the bead surface produces a force that always directs the bead towards the laser focus. This effect is simply due to the geometry of the configuration and can be applied to measure very small forces, like the force between a single myosin and actin molecule.


Neue Publikationen

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Synaptic entrainment of ectopic action potential generation in hippocampal pyramidal neurons. J Physiol. 2018 Aug 24. doi: 10.1113/JP276720. [Epub ahead of print]

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Possible neurotoxicity of the anesthetic propofol: evidence for the inhibition of complex II of the respiratory chain in area CA3 of rat hippocampal slices. Arch Toxicol. 2018 Aug 24. doi: 10.1007/s00204-018-2295-8. [Epub ahead of print]

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Metabolic modulation of neuronal gamma-band oscillations. Pflugers Arch2018 Sep;470(9):1377-1389. doi: 10.1007/s00424-018-2156-6. Epub 2018 May 28.

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Recent advances in hippocampal structure and function. Cell Tissue Res. 2018 Aug 20. doi: 10.1007/s00441-018-2913-z. [Epub ahead of print] Editorial. No abstract available.

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Electrical coupling between hippocampal neurons: contrasting roles of principal cell gap junctions and interneuron gap junctions. Cell Tissue Res. 2018 Aug 15. doi: 10.1007/s00441-018-2881-3. [Epub ahead of print] Review.

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Persistent sodium current modulates axonal excitability in CA1 pyramidal neurons. J Neurochem. 2018 Aug;146(4):446-458. doi: 10.1111/jnc.14479. Epub 2018 Aug 1.

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Selective vulnerability of αOFF retinal ganglion cells during onset of autoimmune optic neuritis. Neuroscience. 2018 Jul 31. pii: S0306-4522(18)30515-3. doi: 10.1016/j.neuroscience.2018.07.040. [Epub ahead of print]

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Strategy for marker-based differentiation of pro- and anti-inflammatory macrophages using matrix-assisted laser desorption/ionization mass spectrometry imaging. Analyst. 2018 Jul 20. doi: 10.1039/c8an00659h. [Epub ahead of print]

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Improving electrical properties of iPSC-cardiomyocytes by enhancing Cx43 expression. J Mol Cell Cardiol. 2018 Jul;120:31-41. doi: 10.1016/j.yjmcc.2018.05.010. Epub 2018 May 16.

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Role of CD40 and ADAMTS13 in von Willebrand factor-mediated endothelial cell-platelet-monocyte interaction. Proc Natl Acad Sci U S A. 2018 Jun 12;115(24):E5556-E5565. doi: 10.1073/pnas.1801366115. Epub 2018 May 23.

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The VAMP-associated protein VAPB is required for cardiac and neuronal pacemaker channel function. FASEB J. 2018 Jun 7:fj201800246R. doi: 10.1096/fj.201800246R. [Epub ahead of print]

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The lncRNA CASC9 and RNA binding protein HNRNPL form a complex and co-regulate genes linked to AKT signaling. Hepatology. 2018 May 23. doi: 10.1002/hep.30102. [Epub ahead of print]

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Early Blood-Brain Barrier Disruption in Ischemic Stroke Initiates Multifocally Around Capillaries/Venules. Stroke. 2018 Jun;49(6):1479-1487. doi: 10.1161/STROKEAHA.118.020927. Epub 2018 May 14.

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Impact of carbonylation on glutathione peroxidase-1 activity in human hyperglycemic endothelial cells. Redox Biol. 2018 Jun;16:113-122. doi: 10.1016/j.redox.2018.02.018. Epub 2018 Mar 1.

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Endothelial progenitor cells accelerate endothelial regeneration in an in vitro model of Shigatoxin-2a-induced injury via soluble growth factors. Am J Physiol Renal Physiol. 2018 Mar 7. doi: 10.1152/ajprenal.00633.2017. [Epub ahead of print]


Institut für
Physiologie und Pathophysiologie

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