title: Supervillin reorganizes the actin cytoskeleton and increases invadopodial efficiency.
abstract: Tumor cells use actin-rich protrusions called invadopodia to degrade extracellular matrix (ECM) and invade tissues; related structures, termed podosomes, are sites of dynamic ECM interaction. We show here that supervillin (SV), a peripheral membrane protein that binds F-actin and myosin II, reorganizes the actin cytoskeleton and potentiates invadopodial function. Overexpressed SV induces redistribution of lamellipodial cortactin and lamellipodin/RAPH1/PREL1 away from the cell periphery to internal sites and concomitantly increases the numbers of F-actin punctae. Most punctae are highly dynamic and colocalize with the podosome/invadopodial proteins, cortactin, Tks5, and cdc42. Cortactin binds SV sequences in vitro and contributes to the formation of enhanced green fluorescent protein (EGFP)-SV induced punctae. SV localizes to the cores of Src-generated podosomes in COS-7 cells and with invadopodia in MDA-MB-231 cells. EGFP-SV overexpression increases average numbers of ECM holes per cell; RNA interference-mediated knockdown of SV decreases these numbers. Although SV knockdown alone has no effect, simultaneous down-regulation of SV and the closely related protein gelsolin reduces invasion through ECM. Together, our results show that SV is a component of podosomes and invadopodia and that SV plays a role in invadopodial function, perhaps as a mediator of cortactin localization, activation state, and/or dynamics of metalloproteinases at the ventral cell surface.
authors.affiliation: Department of Cell Biology and Cell Dynamics Program, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Crowley
authors.forename: Tara C
authors.initials: TC
authors.lastname: Smith
authors.forename: Zhiyou
authors.initials: Z
authors.lastname: Fang
authors.forename: Norio
authors.initials: N
authors.lastname: Takizawa
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Luna
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D019556:COS Cells; D002417:Cattle; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D051356:Cortactin / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D022001:Focal Adhesions / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008840:Microfilament Proteins / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D011554:Pseudopodia / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000199:Actins; D015415:Biomarkers; D051356:Cortactin; D008565:Membrane Proteins; D008840:Microfilament Proteins; D011993:Recombinant Fusion Proteins; C109413:SVIL protein, human; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D019061:src-Family Kinases