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dc.contributor.authorSon, Kyonghee
dc.contributor.authorSmith, Tara C.
dc.contributor.authorLuna, Elizabeth J.
dc.date2022-08-11T08:09:18.000
dc.date.accessioned2022-08-23T16:25:50Z
dc.date.available2022-08-23T16:25:50Z
dc.date.issued2015-02-28
dc.date.submitted2015-03-01
dc.identifier.citationCytoskeleton (Hoboken). 2015 Feb 4. doi: 10.1002/cm.21210. <a href="http://dx.doi.org/10.1002/cm.21210">Link to article on publisher's site</a>
dc.identifier.issn1949-3592 (Linking)
dc.identifier.doi10.1002/cm.21210
dc.identifier.pmid25655724
dc.identifier.urihttp://hdl.handle.net/20.500.14038/36432
dc.description.abstractWe investigated cross-talk between the membrane-associated, myosin II-regulatory protein supervillin and the actin-regulatory small GTPases Rac1, RhoA, and Cdc42. Supervillin knockdown reduced Rac1-GTP loading, but not the GTP loading of RhoA or Cdc42, in HeLa cells with normal levels of the Rac1-activating protein Trio. No reduction in Rac1-GTP loading was observed when supervillin levels were reduced in Trio-depleted cells. Conversely, overexpression of supervillin isoform 1 (SV1) or, especially, isoform 4 (SV4) increased Rac1 activation. Inhibition of the Trio-mediated Rac1 guanine nucleotide exchange (GEF) activity with ITX3 partially blocked the SV4-mediated increase in Rac1-GTP. Both SV4 and SV1 co-localized with Trio at or near the plasma membrane in ruffles and cell surface projections. Two sequences within supervillin bound directly to Trio spectrin repeats 4-7: SV1-171, which contains N-terminal residues found in both SV1 and SV4 and the SV4-specific differentially spliced coding exons 3, 4, and 5 within SV4 (SV4-E345; SV4 amino acids 276 - 669). In addition, SV4-E345 interacted with the homologous sequence in rat kalirin (repeats 4-7, amino acids 531 - 1101). Overexpressed SV1-174 and SV4-E345 affected Rac1-GTP loading, but only in cells with endogenous levels of Trio. Trio residues 771 - 1057, which contain both supervillin-interaction sites, exerted a dominant-negative effect on cell spreading. Supervillin and Trio knockdowns, separately or together, inhibited cell spreading, suggesting that supervillin regulates the Rac1 guanine nucleotide exchange activity of Trio, and potentially also kalirin, during cell spreading and lamellipodia extension. This article is protected by copyright. All rights reserved.
dc.language.isoen_US
dc.relation<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=25655724&dopt=Abstract">Link to Article in PubMed</a>
dc.relation.urlhttp://dx.doi.org/10.1002/cm.21210
dc.subjectCell and Developmental Biology
dc.subjectCell Biology
dc.subjectCellular and Molecular Physiology
dc.subjectMolecular Genetics
dc.titleSupervillin binds the Rac/Rho-GEF trio and increases trio-mediated rac1 activation
dc.typeJournal Article
dc.source.journaltitleCytoskeleton (Hoboken, N.J.)
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/luna/11
dc.identifier.contextkey6753308
html.description.abstract<p>We investigated cross-talk between the membrane-associated, myosin II-regulatory protein supervillin and the actin-regulatory small GTPases Rac1, RhoA, and Cdc42. Supervillin knockdown reduced Rac1-GTP loading, but not the GTP loading of RhoA or Cdc42, in HeLa cells with normal levels of the Rac1-activating protein Trio. No reduction in Rac1-GTP loading was observed when supervillin levels were reduced in Trio-depleted cells. Conversely, overexpression of supervillin isoform 1 (SV1) or, especially, isoform 4 (SV4) increased Rac1 activation. Inhibition of the Trio-mediated Rac1 guanine nucleotide exchange (GEF) activity with ITX3 partially blocked the SV4-mediated increase in Rac1-GTP. Both SV4 and SV1 co-localized with Trio at or near the plasma membrane in ruffles and cell surface projections. Two sequences within supervillin bound directly to Trio spectrin repeats 4-7: SV1-171, which contains N-terminal residues found in both SV1 and SV4 and the SV4-specific differentially spliced coding exons 3, 4, and 5 within SV4 (SV4-E345; SV4 amino acids 276 - 669). In addition, SV4-E345 interacted with the homologous sequence in rat kalirin (repeats 4-7, amino acids 531 - 1101). Overexpressed SV1-174 and SV4-E345 affected Rac1-GTP loading, but only in cells with endogenous levels of Trio. Trio residues 771 - 1057, which contain both supervillin-interaction sites, exerted a dominant-negative effect on cell spreading. Supervillin and Trio knockdowns, separately or together, inhibited cell spreading, suggesting that supervillin regulates the Rac1 guanine nucleotide exchange activity of Trio, and potentially also kalirin, during cell spreading and lamellipodia extension. This article is protected by copyright. All rights reserved.</p>
dc.identifier.submissionpathluna/11
dc.contributor.departmentDepartment of Cell and Developmental Biology, Program in Cell & Developmental Dynamics


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