title: The formins FHOD1 and INF2 regulate inter- and intra-structural contractility of podosomes.
abstract: Podosomes are actin-rich adhesion structures that depend on Arp2/3-complex-based actin nucleation. We now report the identification of the formins FHOD1 and INF2 as novel components and additional actin-based regulators of podosomes in primary human macrophages. FHOD1 surrounds the podosome core and is also present at podosome-connecting cables, whereas INF2 localizes at the podosome cap structure. Using a variety of microscopy-based methods; including a semiautomated podosome reformation assay, measurement of podosome oscillations, FRAP analysis of single podosomes, and structured illumination microscopy, both formins were found to regulate different aspects of podosome-associated contractility, with FHOD1 mediating actomyosin contractility between podosomes, and INF2 regulating contractile events at individual podosomes. Moreover, INF2 was found to be a crucial regulator of podosome de novo formation and size. Collectively, we identify FHOD1 and INF2 as novel regulators of inter- and intra-structural contractility of podosomes. Podosomes thus present as one of the few currently identified structures which depend on the concerted activity of both Arp2/3 complex and specific formins and might serve as a model system for the analysis of complex actin architectures in cells.
authors.affiliation: Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Eppendorf, Martinistraße 52, Hamburg 20246, Germany.
authors.forename: Linda
authors.initials: L
authors.lastname: Panzer
authors.affiliation: Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Eppendorf, Martinistraße 52, Hamburg 20246, Germany.
authors.forename: Leona
authors.initials: L
authors.lastname: Trübe
authors.affiliation: Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Eppendorf, Martinistraße 52, Hamburg 20246, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Klose
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, Nijmegen 6525 GA, The Netherlands.
authors.forename: Ben
authors.initials: B
authors.lastname: Joosten
authors.affiliation: Erasmus University, Wytemaweg 80, Rotterdam 3015 CN, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Slotman
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, Nijmegen 6525 GA, The Netherlands.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cambi
authors.affiliation: Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Eppendorf, Martinistraße 52, Hamburg 20246, Germany s.linder@uke.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Linder
mesh_terms: D000199:Actins / Q000378:metabolism; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000378:metabolism; D005326:Fetal Proteins / Q000502:physiology*; D000080865:Formins; D006801:Humans; D008264:Macrophages / Q000378:metabolism / Q000648:ultrastructure; D008840:Microfilament Proteins / Q000502:physiology*; D009687:Nuclear Proteins / Q000502:physiology*; D000069261:Podosomes / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D000199:Actins; C120021:FHOD1 protein, human; D005326:Fetal Proteins; D000080865:Formins; C546959:INF2 protein, human; D008840:Microfilament Proteins; D009687:Nuclear Proteins
keywords: FHOD1; Formins; INF2; Macrophages; Podosomes