title: Fascin actin bundling controls podosome turnover and disassembly while cortactin is involved in podosome assembly by its SH3 domain in THP-1 macrophages and dendritic cells.
abstract: Podosomes are dynamic degrading devices present in myeloid cells among other cell types. They consist of an actin core with associated regulators, surrounded by an adhesive ring. Both fascin and cortactin are known constituents but the role of fascin actin bundling is still unclear and cortactin research rather focuses on its homologue hematopoietic lineage cell-specific protein-1 (HS1). A fascin nanobody (FASNb5) that inhibits actin bundling and a cortactin nanobody (CORNb2) specifically targeting its Src-homology 3 (SH3) domain were used as unique tools to study the function of these regulators in podosome dynamics in both THP-1 macrophages and dendritic cells (DC). Upon intracellular FASNb5 expression, the few podosomes present were aberrantly stable, long-living and large, suggesting a role for fascin actin bundling in podosome turnover and disassembly. Fascin modulates this by balancing the equilibrium between branched and bundled actin networks. In the presence of CORNb2, the few podosomes formed show disrupted structures but their dynamics were unaffected. This suggests a role of the cortactin SH3 domain in podosome assembly. Remarkably, both nanobody-induced podosome-losses were compensated for by focal adhesion structures. Furthermore, matrix degradation capacities were altered and migratory phenotypes were lost. In conclusion, the cortactin SH3 domain contributes to podosome assembly while fascin actin bundling is a master regulator of podosome disassembly in THP-1 macrophages and DC.
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
authors.forename: Isabel
authors.initials: I
authors.lastname: Van Audenhove
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
authors.forename: Nincy
authors.initials: N
authors.lastname: Debeuf
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
authors.forename: Ciska
authors.initials: C
authors.lastname: Boucherie
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium. Electronic address: jan.gettemans@ugent.be.
authors.forename: Jan
authors.initials: J
authors.lastname: Gettemans
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects; D021982:Cell-Matrix Junctions / Q000187:drug effects / Q000378:metabolism*; D051356:Cortactin / Q000737:chemistry* / Q000378:metabolism*; D003713:Dendritic Cells / Q000187:drug effects / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008840:Microfilament Proteins / Q000378:metabolism*; D008954:Models, Biological; D010641:Phenotype; D059748:Proteolysis / Q000187:drug effects; D061905:Single-Domain Antibodies / Q000494:pharmacology; D013329:Structure-Activity Relationship; D018909:src Homology Domains
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; C495868:CTTN protein, human; D002352:Carrier Proteins; D051356:Cortactin; D008840:Microfilament Proteins; D061905:Single-Domain Antibodies; C020324:fascin
keywords: Actin dynamics; Cortactin; Fascin; Nanobody; Podosome