Opposing Roles of Zyxin/LPP ACTA Repeats and the LIM Domain Region in Cell-Cell Adhesion

Abstract

Cadherins mediate cell-cell adhesion by linking cell junctions to actin networks. Although several actin regulatory systems have been implicated in cell-cell adhesion, it remains unclear how such systems drive cadherin-actin network formation and how they are regulated to coincide with initiation of adhesion. Previous work implicated VASP in assembly of cell-cell junctions in keratinocytes and the VASP-binding protein zyxin colocalizes with VASP at cell-cell junctions. Here we examine how domains in zyxin and its relative LPP contribute to cell-cell junction assembly. Using a quantitative assay for cell-cell adhesion, we demonstrate that zyxin and LPP function to increase the rate of early cell-cell junction assembly through the VASP-binding ActA repeat region. We also identify the LIM region of zyxin and LPP to be a regulatory domain that blocks function of these proteins. Deletion of the LIM domains drives adhesion and increases VASP level in detergent insoluble cadherin-actin. Dominant-negative zyxin/LPP mutants reduce the rate of adhesion, lower VASP levels in detergent-insoluble cadherin-actin networks, and allow for the accumulation of capping protein at cell-cell contacts. These data implicate the LIM domains of zyxin and LPP in regulating cell-cell junction assembly through VASP. Cadherins mediate cell-cell adhesion by linking cell junctions to actin networks. Although several actin regulatory systems have been implicated in cell-cell adhesion, it remains unclear how such systems drive cadherin-actin network formation and how they are regulated to coincide with initiation of adhesion. Previous work implicated VASP in assembly of cell-cell junctions in keratinocytes and the VASP-binding protein zyxin colocalizes with VASP at cell-cell junctions. Here we examine how domains in zyxin and its relative LPP contribute to cell-cell junction assembly. Using a quantitative assay for cell-cell adhesion, we demonstrate that zyxin and LPP function to increase the rate of early cell-cell junction assembly through the VASP-binding ActA repeat region. We also identify the LIM region of zyxin and LPP to be a regulatory domain that blocks function of these proteins. Deletion of the LIM domains drives adhesion and increases VASP level in detergent insoluble cadherin-actin. Dominant-negative zyxin/LPP mutants reduce the rate of adhesion, lower VASP levels in detergent-insoluble cadherin-actin networks, and allow for the accumulation of capping protein at cell-cell contacts. These data implicate the LIM domains of zyxin and LPP in regulating cell-cell junction assembly through VASP. Cadherin-mediated cell-cell adhesion integrates individual cells into tissues (1Nose A. Nagafuchi A. Takeichi M. Cell. 1998; 54: 993-1001Abstract Full Text PDF Scopus (556) Google Scholar). Strong cell-cell adhesion is required to maintain cell morphology and tissue homeostasis (2Gumbiner B.M. Cell. 1996; 84: 345-357Abstract Full Text Full Text PDF PubMed Scopus (2930) Google Scholar). As individual cadherin-cadherin adhesion interactions are weak (3Brieher W.M. Yap A.S. Gumbiner B.M. J. Cell Biol. 1996; 135: 487-496Crossref PubMed Scopus (264) Google Scholar), strong adhesion is thought to require incorporation of cadherin into actin networks (4Hinck L. Nathke I.S. Papkoff J. Nelson W.J. J. Cell Biol. 1994; 125: 1327-1340Crossref PubMed Scopus (556) Google Scholar, 5Angres B. Barth A. Nelson W.J. J. Cell Biol. 1996; 134: 549-557Crossref PubMed Scopus (168) Google Scholar). The cytoplasmic domain of cadherin binds either β-catenin or plakoglobin (6Ozawa M. Baribault H. Kemler R. EMBO J. 1989; 8: 1711-1717Crossref PubMed Scopus (1149) Google Scholar), which in turn binds α-catenin (7Herrenknecht K. Ozawa M. Eckerskorn C. Lottspeich F. Lenter M. Kemler R. Proc. Natl. Acad. Sci. 1991; 88: 9156-9160Crossref PubMed Scopus (296) Google Scholar, 8Rimm D.L. Koslov E.R. Kebriaei P. Cianci C.D. Morrow J.S. Proc. Natl. Acad. Sci. U. S. A. 1995; 92: 8813-8817Crossref PubMed Scopus (633) Google Scholar). α-Catenin links cadherin to actin filaments either directly (8Rimm D.L. Koslov E.R. Kebriaei P. Cianci C.D. Morrow J.S. Proc. Natl. Acad. Sci. U. S. A. 1995; 92: 8813-8817Crossref PubMed Scopus (633) Google Scholar) or by binding the actin-binding proteins vinculin (9Hazan R.B. Kang L. Roe S. Borgen P.I. Rimm D.L. J. Biol. Chem. 1997; 272: 32448-32453Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar) or α-actinin (10Knudsen K.A. Soler A.P. Johnson K.R. Wheelock M.J. J. Cell Biol. 1995; 130: 367-377Crossref Scopus (562) Google Scholar). Cadherin anchors into detergent-insoluble actin networks concomitant with incorporation of α-catenin into cadherin complexes (4Hinck L. Nathke I.S. Papkoff J. Nelson W.J. J. Cell Biol. 1994; 125: 1327-1340Crossref PubMed Scopus (556) Google Scholar, 5Angres B. Barth A. Nelson W.J. J. Cell Biol. 1996; 134: 549-557Crossref PubMed Scopus (168) Google Scholar). However, it remains unclear how binding of cadherin to actin filaments is regulated to coincide with cell-cell adhesion. Although cadherin has been demonstrated to induce dramatic changes in actin organization (11Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1996; 135: 1899-1911Crossref PubMed Scopus (271) Google Scholar, 12Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1998; 142: 1105-1119Crossref PubMed Scopus (429) Google Scholar, 13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar) and several actin regulatory programs have been generally implicated in cell-cell adhesion (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar, 14Helwani F.M. Kovacs E.M. Paterson A.D. Verma S. Ali R.G. Fanning A.S. Weed S.A. Yap A.S. J. Cell Biol. 2004; 164: 899-910Crossref PubMed Scopus (148) Google Scholar), how actin rearrangements and cadherin engagement are coordinated remains poorly understood. Understanding actin assembly mechanisms has been greatly improved by studies of the intracellular pathogen, Listeria monocytogenes (15Beckerle M.C. Cell. 1998; 95: 741-748Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar). Listeria ActA protein hijacks host actin polymerization machinery, directing assembly of actin comet tails that propel the bacterium through the cytosol (16Domann E. Wehland J. Rohde M. Pistor S. Hartl S. Goebel W. Leimeister-Wächter M. Wuenscher M. Chakraborty T. EMBO J. 1992; 11: 1981-1990Crossref PubMed Scopus (326) Google Scholar, 17Kocks C. Gouin E. Tabouret M. Berche P. Ohayon H. Cossart P. Cell. 1992; 68: 521-531Abstract Full Text PDF PubMed Scopus (658) Google Scholar). In addition to actin nucleation by the Arp2/3 complex, normal motility requires the activity of VASP family members (18Chakraborty T. Ebel F. Domann E. Niebuhr K. Gerstel B. Pistor S. Temm-Grove C.J. Jockusch B.M. Reinhard M. Walter U. Wehland J. EMBO J. 1995; 14: 1314-1321Crossref PubMed Scopus (232) Google Scholar) that are recruited via an array of proline-rich motifs termed ActA repeats (19Niebuhr K. Ebel F. Frank R. Reinhard M. Domann E. Carl U.D. Walter U. Gertler F.B. Wehland J. Chakraborty T. EMBO J. 1997; 16: 5433-5444Crossref PubMed Scopus (333) Google Scholar). It has been proposed that VASP competes with capping protein (CapZ) for available barbed ends of actin filaments, protecting the barbed end and allowing continued polymerization (20Bear J.E. Svitkina T.M. Krause M. Schafer D.A. Luoreiro J.J. Strasser G.A. Maly I.V. Chaga O.Y. Cooper J.A. Borisy G.G. Gertler F.B. Cell. 2002; 109: 509-521Abstract Full Text Full Text PDF PubMed Scopus (664) Google Scholar). In such a model, local control of VASP concentration is critical in cellular regulation of actin organization. How cells control local VASP availability to regulate actin dynamics remains unclear. ActA repeats are observed in several mammalian proteins, including zyxin (21Drees B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar) and its LPP Fradelizi J. Golsteyn R.M. B. Louvard Friedrich E. Biol. Cell. 2000; 11: PubMed Scopus Google Scholar). zyxin and LPP are at cell-cell in cells and tissues (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar, Fradelizi J. Golsteyn R.M. B. Louvard Friedrich E. Biol. Cell. 2000; 11: PubMed Scopus Google Scholar, Beckerle M.C. J. Biol. Chem. 1991; Full Text PDF PubMed Google Scholar, D.A. B. R. E. C. A.S. Gertler F.B. Fuchs E. R. Beckerle M.C. Cell. Biol. PubMed Scopus Google Scholar). of ActA repeats into cells and cell-cell junctions (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar, B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar). of the domain of which has been to a VASP in in in cell-cell adhesion that a (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar). these it has been that zyxin VASP to drive actin rearrangements observed cell-cell junction assembly. with a for zyxin in actin of zyxin in local actin assembly (21Drees B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar). of zyxin that to in cells local actin polymerization J. V. J. B. Louvard C. Golsteyn R.M. Friedrich E. Cell Biol. PubMed Scopus Google Scholar). However, for a for zyxin in actin cell-cell junction organization normal in for zyxin D.A. B. R. E. C. A.S. Gertler F.B. Fuchs E. R. Beckerle M.C. Cell. Biol. PubMed Scopus Google Scholar). Here the of zyxin and LPP in cell-cell junction assembly is in in demonstrate that zyxin and LPP drive cell-cell adhesion through of ActA mutants of zyxin or LPP drives cell-cell adhesion and VASP incorporation into actin networks. mutants of zyxin or LPP cell-cell adhesion and of capping protein cell-cell junctions. of zyxin or LPP adhesion. Deletion of the LIM region is required to activity of zyxin or that the LIM region of zyxin and LPP a regulatory domain that of the zyxin/LPP these demonstrate a for zyxin/LPP and VASP in cell-cell junction formation and a for VASP activity in cellular Cell cells in initiation of adhesion by a (4Hinck L. Nathke I.S. Papkoff J. Nelson W.J. J. Cell Biol. 1994; 125: 1327-1340Crossref PubMed Scopus (556) Google Scholar). of the rate of cell-cell adhesion J.S. Nelson W.J. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). cells and at cells of cell the of a tissue in an of the cell either or of the of or of cell cells with or zyxin or LPP by of of proteins in the cells by with the in to and with or binding with the of cells or protein a cell The for cell of cell-cell adhesion in cell of with in for to for with in with and and with the vinculin VASP capping protein zyxin/LPP zyxin and LPP binding with or to or or proteins observed in and a with and with a a and of and cells with and LPP to in the of zyxin and LPP in cell-cell junction assembly and we a cell that has been to adhesion and is to of proteins. mammalian zyxin LPP the of these proteins, cell in and to with these of the observed and and have been observed at cell-cell junctions of keratinocytes the (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar). In for either zyxin or cell-cell junctions observed in or at the of cell-cell junctions are observed in at early cell-cell zyxin into at the end of of actin filaments that at the the cell-cell LPP also to the ends of of actin filaments that at cell-cell junctions These at the cells into and at at the of the of actin is at cell-cell to a with zyxin and LPP are of However, of actin that in of cadherin have also been the early of cell-cell formation in cells (11Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1996; 135: 1899-1911Crossref PubMed Scopus (271) Google Scholar, 12Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1998; 142: 1105-1119Crossref PubMed Scopus (429) Google Scholar). these of we and adhesion with zyxin at these of cadherin observed to the of zyxin of also observed to with zyxin in these VASP and vinculin It be that VASP and vinculin are to to in addition to and that VASP is a binding of zyxin and In with zyxin at these cell-cell and zyxin at at the of of cells We that of actin filaments at cell-cell junctions in of (11Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1996; 135: 1899-1911Crossref PubMed Scopus (271) Google Scholar, 12Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1998; 142: 1105-1119Crossref PubMed Scopus (429) Google Scholar), and that and vinculin to these The cadherin by (11Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1996; 135: 1899-1911Crossref PubMed Scopus (271) Google Scholar, 12Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1998; 142: 1105-1119Crossref PubMed Scopus (429) Google Scholar) be to observed in and vinculin with cadherin at the of actin cells (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar). of and LPP Deletion in zyxin and LPP function in cell-cell adhesion, and proteins and in and LPP organization of several protein domains that for zyxin or LPP proteins These an α-actinin binding in the Beckerle M.C. J. Cell Biol. 1992; PubMed Scopus Google Scholar), a of ActA repeats in in that have been demonstrated to the domains of VASP family members (21Drees B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar, Fradelizi J. Golsteyn R.M. B. Louvard Friedrich E. Biol. Cell. 2000; 11: PubMed Scopus Google Scholar), and a of LIM cells with the zyxin or LPP proteins. of proteins with or by to and a of these cells a cell cell of cell that proteins a of the of mutants to a in protein cells zyxin or LPP proteins and the cell-cell junction of the protein by a of the protein to including cell-cell observed In and cell-cell junction in the α-actinin binding ActA or LIM domains either zyxin or observed Although strong in the cytosol and in the observed for it be that levels of cell-cell junction observed for junction with the junction cadherin of the LIM of and LPP in zyxin or LPP proteins in a quantitative assay for cell-cell junction assembly and J.S. Nelson W.J. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, A.S. G.A. 2000; PubMed Scopus Google Scholar). cells in and to into a function of also to that weak cell-cell the level of cell-cell junctions that have been The are that observed in the rate of formation and the rate at which cells these a of the that a cell be in a relative to the cell for cell and that it is that a cell be in a relative to the cell a that it is that a cell be of a relative to the cell The is with by that for We the for that a cell a in the rate of cell-cell junction the and be either or to be for the cell the or which we the of the for These are and for and Using such is for the adhesion we the data for cell for cell in to cells cells into by for of and for and of in that a is cells are to weak cell-cell cells in is to and of cells are in and in for is by or the of a and junction cells protein either zyxin or LPP and cell-cell junctions at a rate that cells and of either the α-actinin binding or the ActA repeats either zyxin or LPP in the rate of cell-cell junction formation and to and In of proteins either zyxin or LPP that the LIM domain region the rate of cell-cell assembly and to a that and of and cells the cells for of with of of cells in or with of the cell for of cells for The rate of cell-cell is also in cell or in of cells in with of of cells in with of for and of cells and the rate of and is in these cell a of cells in have cell-cell interactions to by in of cells in with of of cells in in the LIM region is critical for zyxin and LPP function in cell-cell adhesion. the observed be for by the is of the proteins the and it is by of the LIM region that an is the LIM and the for changes in cell-cell adhesion We also observed that cells proteins LIM domain zyxin at levels an a protein zyxin at levels H. is with the observed with that of the LIM domain the function of zyxin and LPP in cell-cell adhesion. to of of either zyxin or LPP mutants LIM domains in formation and of cell-cell interactions zyxin and LPP to function in early cell-cell that zyxin and LPP mutants drive changes in cell-cell junction formation of cell-cell in the adhesion we to how zyxin/LPP in cells relative to cadherin cell-cell adhesion been and to for cells in at cell for and at in cells are to cell-cell interactions into levels are in in of adhesion. the initiation of cell-cell adhesion, cells and allowing the of the detergent insoluble cadherin-actin In these cadherin of or cell-cell that with zyxin/LPP of cell-cell cadherin are observed and cadherin the cell-cell of cadherin in these cells are of zyxin/LPP zyxin/LPP a of the cadherin with the of the zyxin and LPP these data that zyxin and LPP function early and in the formation and of cell-cell junctions. the of zyxin/LPP at the of adhesion that the of for these proteins in cell-cell junction formation is at cadherin and LPP through ActA for the that of the zyxin or LPP LIM adhesion is that the LIM region an activity that cell-cell adhesion. the that of the zyxin or LPP LIM domains the rate of adhesion However, be in we in adhesion either the zyxin or LPP LIM region is the for these cell relative to the The zyxin or LPP LIM region cell-cell junction the is in the and by which zyxin and LPP mutants LIM domains drive of cell-cell be the function of the LIM domains is to regulate an activity that the LIM region. such the of the LIM region an activity that cell-cell adhesion. is to strong cell-cell adhesion, the protein of zyxin and LPP ActA and zyxin and LPP with VASP at cell-cell we that zyxin and LPP drive changes in cell-cell adhesion through ActA the LIM domains of zyxin and LPP a regulatory domain that normal of the ActA of the ActA repeats in addition to the LIM domains zyxin and LPP mutants that are to drive cell-cell formation and with cells a in the rate of cell-cell junction assembly with cells for of cells of cell-cell of cells and of cells cells also a rate of cell-cell formation with cells observed in cells in of these cells observed in and in of ActA repeats a in the rate at which cell-cell adhesion is and of formation of cells in the are to and in for and of are to for and cells These that the ActA repeats are for the rate of cell and of cell-cell interactions observed the or are we that and cells cell-cell junctions at a rate that is the cell We of the ActA repeats and LIM domains of zyxin or LPP the of these proteins to cell-cell in of either or that these proteins to cell-cell of and VASP at cell-cell they are to detergent with to at detergent insoluble cadherin-actin networks. These that the incorporation of zyxin into cadherin-actin networks is VASP. VASP be required to zyxin into the cadherin-actin an ActA repeat or cell-cell (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar, B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar). is the that VASP activity is required for the of zyxin into detergent insoluble cadherin-actin networks. LIM Deletion of VASP and at zyxin or LPP the incorporation of actin regulatory proteins into the cadherin-actin network at cell-cell we how the of VASP and capping protein by in the activity of either zyxin or and cells levels of VASP at cell-cell junctions with or cells However, cells are to proteins into detergent insoluble a in VASP is cells cell-cell junction with VASP cell-cell junctions of cells with VASP The of VASP that detergent is that of cells or cells zyxin or LPP is observed in cells LPP It be that LPP ActA of which binds VASP in Fradelizi J. Golsteyn R.M. B. Louvard Friedrich E. Biol. Cell. 2000; 11: PubMed Scopus Google Scholar), with ActA repeats in zyxin (15Beckerle M.C. Cell. 1998; 95: 741-748Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar, B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar). for the in VASP in cells with cells VASP has been proposed to increase actin polymerization by binding actin barbed ends and capping protein (20Bear J.E. Svitkina T.M. Krause M. Schafer D.A. Luoreiro J.J. Strasser G.A. Maly I.V. Chaga O.Y. Cooper J.A. Borisy G.G. Gertler F.B. Cell. 2002; 109: 509-521Abstract Full Text Full Text PDF PubMed Scopus (664) Google Scholar). VASP binding is proposed to allow barbed ends to polymerization (20Bear J.E. Svitkina T.M. Krause M. Schafer D.A. Luoreiro J.J. Strasser G.A. Maly I.V. Chaga O.Y. Cooper J.A. Borisy G.G. Gertler F.B. Cell. 2002; 109: 509-521Abstract Full Text Full Text PDF PubMed Scopus (664) Google Scholar), capping protein of the actin barbed end J.E. V. Cooper J.A. 1989; PubMed Scopus Google Scholar). the VASP and capping protein availability at actin barbed ends be regulated to control actin in zyxin and LPP function to regulate the of VASP and capping protein activity at cell-cell the of capping protein in cells and cells zyxin or LPP mutants cells of capping protein at cell-cell junctions cells zyxin or LPP In and cells an level of capping protein at cell-cell junctions with or cells or to the cell capping protein at cell-cell junctions Although a observed in cells LPP cells capping protein at cell-cell junctions with the relative of VASP binding ActA repeats in zyxin and LPP or of zyxin mutants in VASP and capping protein at of LPP The of zyxin and LPP mutants the of VASP and capping protein at cell-cell junctions is with the that zyxin and LPP drive cell-cell adhesion through by regulating polymerization at actin barbed rearrangements by cadherin engagement have been in several cell (11Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1996; 135: 1899-1911Crossref PubMed Scopus (271) Google Scholar, 12Adams C.L. Chen Y.T. Smith S.J. Nelson W.J. J. Cell Biol. 1998; 142: 1105-1119Crossref PubMed Scopus (429) Google Scholar, 13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar). has been to the of actin nucleation in cell-cell adhesion S. J.A. F.M. H. T. Yap A.S. J. Biol. Chem. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar, E.M. M. Ali R.G. Paterson A.D. Yap A.S. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). is how actin regulatory also contribute to adhesion and how these be by cadherin and A. B. T. R. to the Scholar) proposed that zyxin VASP into cadherin complexes by binding VASP regulate local changes in actin In of VASP to cell-cell junctions of it is with zyxin (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar). of the VASP to a in the of in a and keratinocytes cell-cell junction morphology (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar). In such a model, it remains unclear function is by VASP in cadherin-actin network it is unclear how the of zyxin and VASP to cell-cell junctions is coordinated to coincide with cell-cell adhesion. The in a level of in how zyxin through VASP and VASP family members that also zyxin or LPP ActA in cell-cell adhesion. that the of zyxin to VASP is by an It is the LIM region of zyxin and LPP that a regulatory zyxin/LPP mutants the LIM region cell-cell adhesion, of the LIM region in cell-cell junction formation The of VASP to into the actin at cell-cell is in cells LIM region of zyxin or LPP In incorporation of VASP into actin networks at cell-cell junctions is in cells zyxin or LPP mutants that the regulatory LIM region and ActA demonstrated by capping protein of cell-cell junctions These mutants are to increases of VASP activity in to cadherin Although we VASP activity the of VASP to with the detergent insoluble actin is with a the LIM region of zyxin and LPP VASP The observed accumulation of capping protein at cell-cell in cells the of VASP incorporation into detergent insoluble cadherin-actin networks, that VASP activity is VASP at cell-cell junctions and its be we the that the LIM region VASP activity and VASP to cell-cell junctions. It is critical that the by which the LIM region the function of these proteins in cell-cell adhesion be and LPP with VASP at cell-cell junctions at that at cadherin the cell-cell at the zyxin and LPP mutants cell-cell adhesion of zyxin/LPP and cadherin is observed The that zyxin and LPP function in cell-cell adhesion is by several The mutants of protein in mutants of these proteins cell-cell adhesion at the The of zyxin and LPP at cell-cell junction also that these proteins zyxin a normal D.A. B. R. E. C. A.S. Gertler F.B. Fuchs E. R. Beckerle M.C. Cell. Biol. PubMed Scopus Google Scholar). It be in work to the of these proteins in the The of ActA repeats in zyxin to that zyxin regulate actin assembly. In of zyxin to actin at the Beckerle M.C. J. Biol. Chem. 1991; Full Text PDF PubMed Google Scholar) and binds VASP via its ActA repeats (21Drees B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar). The is that zyxin actin assembly by VASP family members to cellular of zyxin has been to drive local actin and it is of the that these studies zyxin that the LIM domain region (21Drees B. Friedrich E. Fradelizi J. Louvard J. Beckerle M.C. Golsteyn R.M. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar, J. V. J. B. Louvard C. Golsteyn R.M. Friedrich E. Cell Biol. PubMed Scopus Google Scholar). that such zyxin VASP in an It has been that with the of VASP family members to with ActA proteins cell-cell adhesion (13Vasioukhin V. Bauer C. Yin M. Fuchs E. Cell. 2000; 100: 209-219Abstract Full Text Full Text PDF PubMed Scopus (943) Google Scholar). Here we these and that zyxin and LPP VASP to a in the of cell-cell activity is regulated by the LIM of these proteins and the VASP binding ActA repeats in the of zyxin and into the function of zyxin and the of proteins that VASP family members to of VASP family The capping protein by J. Cooper the the of the and by the of of We the members of the Beckerle and in the of the We also for with of cell-cell adhesion