BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//6.4.7.2//EN TZID:Europe/Paris X-WR-TIMEZONE:Europe/Paris BEGIN:VEVENT UID:0-1060@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20260123T110000 DTEND;TZID=Europe/Paris:20260123T120000 DTSTAMP:20260119T091553Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i nterface-seminar-alexander-bershadsky/ SUMMARY:Physics-Biology Interface seminar: Alexander Bershadsky - Salle pol yvalente de l'Institut Curie\, bâtiment 111 - 23 Jan 26 11:00 DESCRIPTION:Integrin mediated cell-matrix adhesions and their regulation by microtubules\nAlexander D. Bershadsky (Natl. U. of Singapore &\; Weizm ann Institute)\n\nMind the unusual location\; unlike the the plateau cante en the one near Curie is functional!\n\nThe seminar will exceptionally be broadcasted over Zoom:\nhttps://cnrs.zoom.us/j/99232320872?pwd=PXHM7HB0jJc ksEL8AD6PjcFcifMDck.1\nMeeting ID: 992 3232 0872\nPasscode: Mg0F5N\n\n\nWe discuss here two major types of cell-matrix adhesions mediated by transme mbrane receptors of integrin family - focal adhesions\, formed by cells on locally flat surfaces coated with extracellular matrix proteins (integrin ligands)\, and fibrillar adhesions\, associated with cell-derived fibrils containing protein fibronectin. Focal adhesions are linked with actin fil ament bundles and probing the matrix stiffness by transmitting and sensing forces. Activation/inactivation of myosin-II contractility trigger assemb ly/disassembly of focal adhesions\, respectively. Unlike focal adhesions\, fibrillar adhesions associate with sparse actin network and do not disass emble upon myosin-II inhibition. Moreover\, specific nano-topographical cu es – nanofibers or nanogrooves – trigger formation of fibrillar adhesi ons in a myosin-II-independent fashion\, while excessive activation of myo sin II\, or increase of membrane tension\, trigger the disassembly of fibr illar adhesions. Theoretical modelling and experimental data suggest that formation of fibrillar adhesions along nano-topographical cues can be expl ained by a special shape of adhesion receptors\, preferably connecting the cell and substrate surfaces tilted relatively to each other. The shape of α5β1 integrin\, the only one found in fibrillar adhesions\, satisfies t o this condition. Microtubules are targeted to focal and fibrillar adhesio ns via KANK family proteins. Using genetic depletion and optogenetic tools \, we deciphered mechanism of microtubule-driven adhesion regulation. Disc onnecting microtubules from integrin adhesions triggers the release of mic rotubule-associated Rho activator GEF-H1\, subsequent activation of Rho an d assembly of myosin II filaments\, which then remodel the focal and fibri llar adhesions in a differential manner\, as described above. Thus\, micro tubules function as signaling structures locally regulating myosin II cont ractility in response to their interactions with integrin adhesions.\n\nFu rther reading\n\nRafiq NBM\, … Bershadsky AD. A mechano-signalling netwo rk linking microtubules\, myosin IIA filaments and integrin-based adhesion s. Nat Mater. 2019\;18(6):638-649.\nAureille J\, … Bershadsky AD. Focal adhesions are controlled by microtubules through local contractility regul ation. EMBO J. 2024\; 43(13):2715-2732.\nFarrugia AJ ... Bershadsky AD. Fi brillar adhesions are the primary integrin complexes shaped by matrix topo graphy. bioRxiv 2025\; 2025.11.26.690075.\n\n CATEGORIES:physbio,seminars LOCATION:Salle polyvalente de l'Institut Curie\, bâtiment 111\, 111\, Rue Jean-Dominique Cassini\, Bures-sur-Yvette\, 91440\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=111\, Rue Jean-Dominique Ca ssini\, Bures-sur-Yvette\, 91440\, France;X-APPLE-RADIUS=100;X-TITLE=Salle polyvalente de l'Institut Curie\, bâtiment 111:geo:0,0 END:VEVENT BEGIN:VTIMEZONE TZID:Europe/Paris X-LIC-LOCATION:Europe/Paris BEGIN:STANDARD DTSTART:20251026T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD END:VTIMEZONE END:VCALENDAR