{"586127":{"#nid":"586127","#data":{"type":"event","title":"Microscopic origins of extensile versus contractile active stress in cytoskeletal motor-filament systems","body":[{"value":"\u003Ch3\u003E\u003Cstrong\u003ESoft Condensed Matter \u0026amp; Physics of Living Systems Seminar: Prof. Meredith Betterton,\u0026nbsp;University of Colorado.\u003C\/strong\u003E\u003C\/h3\u003E\r\n\r\n\u003Cp\u003EThe\u0026nbsp;cytoskeleton, despite\u0026nbsp;comprising relatively few building blocks, drives an impressive variety of cellular phenomena ranging from\u0026nbsp;cell division to motility. These building blocks include filaments such as microtubules and actin, motor proteins such as kinesins and myosins, and static\u0026nbsp;crosslinkers. Outside of\u0026nbsp;cells, these same\u0026nbsp;components\u0026nbsp;can form novel materials exhibiting active flows and\u0026nbsp;nonequilibrium\u0026nbsp;contraction or extension.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EReconstituted actin-myosin mixtures typically\u0026nbsp;contract, and microtubule-kinesin mixtures typically extend along the filament axis. A longstanding puzzle is the microscopic origin of active\u0026nbsp;stresses\u0026nbsp;in motor-filament mixtures and the mechanisms underlying the balance between\u0026nbsp;contraction and extension.\u0026nbsp; Using a minimal physical model of filaments,\u0026nbsp;crosslinking motors, and static\u0026nbsp;crosslinkers we dissect the microscopic mechanisms of\u0026nbsp;stress\u0026nbsp;generation.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EWe demonstrate the essential role of filament steric interactions and develop a unified picture of active forces in motor-filament systems. With this insight, we are able to tunecontractile or\u0026nbsp;extensile\u0026nbsp;behavior through\u0026nbsp;control of motor-driven filament sliding and\u0026nbsp;crosslinking. Our results help explain why flowing reconstituted motor-filament mixtures are\u0026nbsp;extensile\u0026nbsp;while gelled systems arecontractile.\u0026nbsp;This work provides a roadmap for engineering\u0026nbsp;stresses\u0026nbsp;in\u0026nbsp;cytoskeletal active matter and a framework for understanding the\u0026nbsp;cellular\u0026nbsp;cytoskeleton.\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Microscopic origins of extensile versus contractile active stress in cytoskeletal motor-filament systems"}],"uid":"30957","created_gmt":"2017-01-18 18:38:01","changed_gmt":"2017-04-13 21:13:15","author":"Shaun Ashley","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2017-01-31T15:00:00-05:00","event_time_end":"2017-01-31T16:00:00-05:00","event_time_end_last":"2017-01-31T16:00:00-05:00","gmt_time_start":"2017-01-31 20:00:00","gmt_time_end":"2017-01-31 21:00:00","gmt_time_end_last":"2017-01-31 21:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"126011","name":"School of Physics"}],"categories":[],"keywords":[{"id":"166937","name":"School of Physics"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"78751","name":"Undergraduate students"},{"id":"174045","name":"Graduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003Eshaun.ashley@physics.gatech.edu\u003C\/p\u003E\r\n","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}