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UID:DSC-982
DTSTART;TZID=Europe/Berlin:20110217T110000
SEQUENCE:1306506929
TRANSP:OPAQUE
DTEND;TZID=Europe/Berlin:20110217T120000
URL:https://dresden-science-calendar.de/calendar/en/detail/982
LOCATION:MPI-CBG\, Pfotenhauerstraße 10801307 Dresden
SUMMARY:Falcke: A mechanism for actin based propulsion in morpho-dynamics\,
  the force-velocity relation of fish keratocytes and reconstituted systems
CLASS:PUBLIC
DESCRIPTION:Speaker: Martin Falcke\nInstitute of Speaker: Max Delbrück Cen
 ter for Molecular Medicine Berlin\, Germany\nTopics:\nBiologie\n Location:
 \n  Name: MPI-CBG (Seminar room Galleria)\n  Street: Pfotenhauerstraße 10
 8\n  City: 01307 Dresden\n  Phone: +49 351 210-0\n  Fax: +49 351 210-2000\
 nDescription: The morpho‐dynamics of the lamellipodium leading edge have
  been shown to exhibit a few  phenotypes\, which are controlled by cell si
 gnaling (1). The variety of phenotypes reveals the internal  dynamics of a
 ctin polymerization and retrograde flow inside the lamellipodium. Measurem
 ents of  the force‐velocity relation of motile fish keratocytes with an 
 AFM cantilever represent another  dynamic experiment allowing for drawing 
 conclusions on the internal processes (2).  Actin based motility has been 
 reconstituted with ActA coated oil droplets (3) and ActA coated beads  (4)
 . Both systems exhibit steady and saltatory motion.  We present a mathemat
 ical model of actin based propulsion which provides a mechanism for  veloc
 ity oscillations of Listeria (5)\, beads and oil droplets (6). It also des
 cribes the mechanisms of the  morpho‐dynamic phenotypes (7) and the forc
 e velocity relation. The model accounts for the existence  of two function
 ally different regions of the lamellipodium actin network observed in many
  studies (8).  Network behavior is dominated by semi-flexible properties o
 f filaments near the leading edge  membrane\, and it is more gel-like furt
 her towards the cell body (9). We include actin polymerization\,  filament
  binding to the leading edge membrane\, retrograde flow\, contraction of t
 he actin network by  myosin and a simple description of cell adhesion to t
 he substrate into the model.  1. Machacek\, M.\, and G. Danuser. 2006. Mor
 phodynamic Profiling of Protrusion Phenotypes.  Biophys J 90:1439‐1452. 
  2. Prass\, M.\, K. Jacobson\, A. Mogilner\, and M. Radmacher. 2006. Direc
 t measurement of the  lamellipodial protrusive force in a migrating cell. 
 J. Cell Biol. 174:767‐772.  3. Trichet\, L.\, O. Camp? s\, C. Sykes\, an
 d J. Plastino. 2007. VASP Governs Actin Dynamics by  Modulating Filament A
 nchoring. Biophysical Journal 92:1081‐1089.  4. Bernheim‐Groswasser\, 
 A.\, J. Prost\, and C. Sykes. 2005. Mechanism of Actin‐Based Motility: A
   Dynamic State Diagram. Biophys J 89:1411‐1419.  5. Gholami\, A.\, M. F
 alcke\, and E. Frey. 2008. Velocity oscillations in actin‐based motility
 . New  Journal of Physics 10:033022.  6. Enculescu\, M.\, A. Gholami\, and
  M. Falcke. 2008. Dynamic regimes and bifurcations in a model  of actin‐
 based motility. Physical Review E 78:031915.  7. Enculescu\, M.\, M. Sabou
 ri‐Ghomi\, G. Danuser\, and M. Falcke. 2010. Modeling of Protrusion  Phe
 notypes Driven by the Actin‐Membrane Interaction. Biophysical Journal 98
 :1571‐1581.  8. Zimmermann\, J.\, M. Enculescu\, and M. Falcke. 2010. Le
 ading edge ‐ gel coupling in  lamellipodium motion. Physical Review E 82
 :051925.  9. Laurent\, V. M.\, S. Kasas\, A. Yersin\, T. E. Schäffer\, S.
  Catsicas\, G. Dietler\, A. B. Verkhovsky\, and  J.‐J. Meister. 2005. Gr
 adient of Rigidity in the Lamellipodia of Migrating Cells Revealed by  Ato
 mic Force Microscopy. Biophys J 89:667‐675.  
DTSTAMP:20260727T144314Z
CREATED:20110527T143529Z
LAST-MODIFIED:20110527T143529Z
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