title: Formin-mediated actin polymerization at endothelial junctions is required for vessel lumen formation and stabilization.
abstract: During blood vessel formation, endothelial cells (ECs) establish cell-cell junctions and rearrange to form multicellular tubes. Here, we show that during lumen formation, the actin nucleator and elongation factor, formin-like 3 (fmnl3), localizes to EC junctions, where filamentous actin (F-actin) cables assemble. Fluorescent actin reporters and fluorescence recovery after photobleaching experiments in zebrafish embryos identified a pool of dynamic F-actin with high turnover at EC junctions in vessels. Knockdown of fmnl3 expression, chemical inhibition of formin function, and expression of dominant-negative fmnl3 revealed that formin activity maintains a stable F-actin content at EC junctions by continual polymerization of F-actin cables. Reduced actin polymerization leads to destabilized endothelial junctions and consequently to failure in blood vessel lumenization and lumen instability. Our findings highlight the importance of formin activity in blood vessel morphogenesis.
authors.affiliation: Vascular Patterning Laboratory, Vesalius Research Center, VIB, Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
authors.forename: Li-Kun
authors.initials: LK
authors.lastname: Phng
authors.affiliation: Vascular Biology Laboratory, London Research Institute, Cancer Research UK, London WC2A 3LY, UK.
authors.forename: Véronique
authors.initials: V
authors.lastname: Gebala
authors.affiliation: Computational Biology Laboratory, Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Katie
authors.initials: K
authors.lastname: Bentley
authors.affiliation: Centre for Computational Neuroscience and Robotics, Department of Informatics, University of Sussex, Brighton BN1 9QJ, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Philippides
authors.affiliation: Vascular Patterning Laboratory, Vesalius Research Center, VIB, Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
authors.forename: Andrin
authors.initials: A
authors.lastname: Wacker
authors.affiliation: Vascular Patterning Laboratory, Vesalius Research Center, VIB, Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mathivet
authors.affiliation: Biozentrum der Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
authors.forename: Loïc
authors.initials: L
authors.lastname: Sauteur
authors.affiliation: Vascular Patterning Laboratory, Vesalius Research Center, VIB, Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
authors.forename: Fabio
authors.initials: F
authors.lastname: Stanchi
authors.affiliation: Biozentrum der Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
authors.forename: Heinz-Georg
authors.initials: HG
authors.lastname: Belting
authors.affiliation: Biozentrum der Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Affolter
authors.affiliation: Vascular Patterning Laboratory, Vesalius Research Center, VIB, Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium; Vascular Biology Laboratory, London Research Institute, Cancer Research UK, London WC2A 3LY, UK. Electronic address: holger.gerhardt@mdc-berlin.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Gerhardt
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D022005:Adherens Junctions / Q000502:physiology; D000818:Animals; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D000080865:Formins; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D060172:Morpholinos / Q000494:pharmacology; D018919:Neovascularization, Physiologic; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D058105:Polymerization; D015398:Signal Transduction; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; C578075:FMNL3 protein, zebrafish; D000080865:Formins; D008565:Membrane Proteins; D060172:Morpholinos; D016376:Oligonucleotides, Antisense; D029961:Zebrafish Proteins