Select languageSelect language
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.

 

more movies

 

 

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

*

Selective vulnerability of αOFF retinal ganglion cells during onset of autoimmune optic neuritis. Neuroscience. 2018 Nov 21;393:258-272. doi: 10.1016/j.neuroscience.2018.07.040. Epub 2018 Aug 1.

*

Genetic ablation of NFAT5/TonEBP in smooth muscle cells impairs flow- and pressure-induced arterial remodeling in mice. FASEB J. 2018 Nov 1:fj201801594R. doi: 10.1096/fj.201801594R. [Epub ahead of print]

*

Synaptic entrainment of ectopic action potential generation in hippocampal pyramidal neurons.  J Physiol. 2018 Nov;596(21):5237-5249. doi: 10.1113/JP276720. Epub 2018 Sep 19.

*

The Long Noncoding RNA Cancer Susceptibility 9 and RNA Binding Protein Heterogeneous Nuclear Ribonucleoprotein L Form a Complex and Coregulate Genes Linked to AKT Signaling. Hepatology. 2018 Nov;68(5):1817-1832. doi: 10.1002/hep.30102. Epub 2018 Oct 12.

*

Reduction of Transplant Vasculopathy by Intraoperative Nucleic Acid-based Therapy in a Mouse Aortic Allograft Model. Thorac Cardiovasc Surg. 2018 Oct 23. doi: 10.1055/s-0038-1673633. [Epub ahead of print]

*

Early appearance and spread of fast ripples in the hippocampus in a model of cortical traumatic brain injury. J Neurosci. 2018 Oct 17;38(42):9034-9046. doi: 10.1523/JNEUROSCI.3507-17.2018. Epub 2018 Sep 6.

*

High-fat diet suppresses the positive effect of creatine supplementation on skeletal muscle function by reducing protein expression of IGF-PI3K-AKT-mTOR pathway. PLoS One. 2018 Oct 4;13(10):e0199728. doi: 10.1371/journal.pone.0199728. eCollection 2018.

*

Alcohol reduces muscle fatigue through atomistic interactions with nicotinic receptors. Commun Biol. 2018 Oct 3;1:159. doi: 10.1038/s42003-018-0157-9. eCollection 2018.

*

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 Oct;92(10):3191-3205. doi: 10.1007/s00204-018-2295-8. Epub 2018 Aug 24.

*

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 Oct 1;315(4):F861-F869. doi: 10.1152/ajprenal.00633.2017. Epub 2018 Mar 7.

*

Strategy for marker-based differentiation of pro- and anti-inflammatory macrophages using matrix-assisted laser desorption/ionization mass spectrometry imaging. Analyst. 2018 Sep 10;143(18):4273-4282. doi: 10.1039/c8an00659h. Epub 2018 Jul 20.

*

Recent advances in hippocampal structure and function. Cell Tissue Res. 2018 Sep;373(3):521-523. doi: 10.1007/s00441-018-2913-z. Epub 2018 Aug 20. doi: 10.1007/s00441-018-2913-z. Editorial. No abstract available.

*

Electrical coupling between hippocampal neurons: contrasting roles of principal cell gap junctions and interneuron gap junctions. Cell Tissue Res. 2018 Sep;373(3):671-691. doi: 10.1007/s00441-018-2881-3. Epub 2018 Aug 15. Review.

*

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.

*

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]


Institut für
Physiologie und Pathophysiologie

Universität Heidelberg

Im Neuenheimer Feld 326

69120 Heidelberg

Telefon:+49 6221 54-4035
Telefax:+49 6221 54-4038
E-Mail:sekretariat.hecker@
physiologie.uni-heidelberg.de