title: Insights into the origin of metazoan filopodia and microvilli.
abstract: Filopodia are fine actin-based cellular projections used for both environmental sensing and cell motility, and they are essential organelles for metazoan cells. In this study, we reconstruct the origin of metazoan filopodia and microvilli. We first report on the evolutionary assembly of the filopodial molecular toolkit and show that homologs of many metazoan filopodial components, including fascin and myosin X, were already present in the unicellular or colonial progenitors of metazoans. Furthermore, we find that the actin crosslinking protein fascin localizes to filopodia-like structures and microvilli in the choanoflagellate Salpingoeca rosetta. In addition, homologs of filopodial genes in the holozoan Capsaspora owczarzaki are upregulated in filopodia-bearing cells relative to those that lack them. Therefore, our findings suggest that proteins essential for metazoan filopodia and microvilli are functionally conserved in unicellular and colonial holozoans and that the last common ancestor of metazoans bore a complex and specific filopodial machinery.
authors.affiliation: Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain.
authors.forename: Arnau
authors.initials: A
authors.lastname: Sebé-Pedrós
authors.forename: Pawel
authors.initials: P
authors.lastname: Burkhardt
authors.forename: Núria
authors.initials: N
authors.lastname: Sánchez-Pons
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Fairclough
authors.forename: B Franz
authors.initials: BF
authors.lastname: Lang
authors.forename: Nicole
authors.initials: N
authors.lastname: King
authors.forename: Iñaki
authors.initials: I
authors.lastname: Ruiz-Trillo
mesh_terms: D000199:Actins / Q000145:classification; D000818:Animals; D005075:Biological Evolution; D002352:Carrier Proteins / Q000145:classification; D002465:Cell Movement / Q000502:physiology; D056897:Choanoflagellata / Q000145:classification* / Q000235:genetics; D018260:Gelsolin / Q000145:classification; D006801:Humans; D050298:Mesomycetozoea / Q000145:classification* / Q000235:genetics; D008840:Microfilament Proteins / Q000145:classification; D008871:Microvilli / Q000145:classification* / Q000235:genetics; D009218:Myosins / Q000145:classification; D010802:Phylogeny; D011554:Pseudopodia / Q000145:classification* / Q000235:genetics; D020764:cdc42 GTP-Binding Protein / Q000145:classification
chemical_list: D000199:Actins; D002352:Carrier Proteins; D018260:Gelsolin; C498718:MYO10 protein, human; D008840:Microfilament Proteins; C020324:fascin; D009218:Myosins; D020764:cdc42 GTP-Binding Protein
keywords: Capsaspora; Cdc42; choanoflagellate; fascin; filopodia; formin evolution; gelsolin evolution; pseudopodia