--- res: bibo_abstract: - Using correlated live-cell imaging and electron tomography we found that actin branch junctions in protruding and treadmilling lamellipodia are not concentrated at the front as previously supposed, but link actin filament subsets in which there is a continuum of distances from a junction to the filament plus ends, for up to at least 1 mm. When branch sites were observed closely spaced on the same filament their separation was commonly a multiple of the actin helical repeat of 36 nm. Image averaging of branch junctions in the tomograms yielded a model for the in vivo branch at 2.9 nm resolution, which was comparable with that derived for the in vitro actin- Arp2/3 complex. Lamellipodium initiation was monitored in an intracellular wound-healing model and was found to involve branching from the sides of actin filaments oriented parallel to the plasmalemma. Many filament plus ends, presumably capped, terminated behind the lamellipodium tip and localized on the dorsal and ventral surfaces of the actin network. These findings reveal how branching events initiate and maintain a network of actin filaments of variable length, and provide the first structural model of the branch junction in vivo. A possible role of filament capping in generating the lamellipodium leaflet is discussed and a mathematical model of protrusion is also presented.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Marlene foaf_name: Vinzenz, Marlene foaf_surname: Vinzenz - foaf_Person: foaf_givenName: Maria foaf_name: Nemethova, Maria foaf_surname: Nemethova foaf_workInfoHomepage: http://www.librecat.org/personId=34E27F1C-F248-11E8-B48F-1D18A9856A87 - foaf_Person: foaf_givenName: Florian foaf_name: Schur, Florian foaf_surname: Schur foaf_workInfoHomepage: http://www.librecat.org/personId=48AD8942-F248-11E8-B48F-1D18A9856A87 orcid: 0000-0003-4790-8078 - foaf_Person: foaf_givenName: Jan foaf_name: Mueller, Jan foaf_surname: Mueller - foaf_Person: foaf_givenName: Akihiro foaf_name: Narita, Akihiro foaf_surname: Narita - foaf_Person: foaf_givenName: Edit foaf_name: Urban, Edit foaf_surname: Urban - foaf_Person: foaf_givenName: Christoph foaf_name: Winkler, Christoph foaf_surname: Winkler - foaf_Person: foaf_givenName: Christian foaf_name: Schmeiser, Christian foaf_surname: Schmeiser - foaf_Person: foaf_givenName: Stefan foaf_name: Koestler, Stefan foaf_surname: Koestler - foaf_Person: foaf_givenName: Klemens foaf_name: Rottner, Klemens foaf_surname: Rottner - foaf_Person: foaf_givenName: Guenter foaf_name: Resch, Guenter foaf_surname: Resch - foaf_Person: foaf_givenName: Yuichiro foaf_name: Maéda, Yuichiro foaf_surname: Maéda - foaf_Person: foaf_givenName: John foaf_name: Small, John foaf_surname: Small bibo_doi: 10.1242/jcs.107623 bibo_issue: '11' bibo_volume: 125 dct_date: 2012^xs_gYear dct_language: eng dct_publisher: Company of Biologists@ dct_title: Actin branching in the initiation and maintenance of lamellipodia@ ...