Phosphorylation-independent membrane relocalization of ezrin following association with Dbl in vivo

Vanni, Cristina; Parodi, Alessia; Mancini, Patrizia; Visco, Vincenzo; Ottaviano, Catherine; Torrisi, Maria Rosaria; Eva, Alessandra

doi:10.1038/sj.onc.1207509

Cited by 21 publications

(32 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mechanistically, ERM proteins have been implicated in the regulation of the Rho family of small GTPases either through inhibition of the Rho-specific GDP dissociation inhibitor RhoGDI (Takahashi et al, 1997) or through interaction with the Cdc42/Rhospecific guanine exchange factor Dbl (Vanni et al, 2004). The functional consequence of the ERM-Dbl complex on Rho GTPase activity has to date however only been demonstrated for RhoA.…”

Section: Discussionmentioning

confidence: 99%

“…As ezrin has previously been shown to interact with Dbl via the PH domain (Vanni et al, 2004), we analyzed the affects of N-ERMAD(E244K) on the subcellular localization of Dbl as a potential target for inhibiting Cdc42 activation. Endogenous Dbl is predominantly localized to the plasma membrane and in the cytoplasm overlapping with the localization of full-length ezrin ( Figure 9A), similar to that reported previously (Vanni et al, 2004). In the presence of N-ERMAD(E244K), the endogenous Dbl failed to be recruited to the plasma membrane and showed no colocalization with N-ERMAD(E244K) ( Figure 9A).…”

Section: Expression Of N-ermad(e244k) Inhibits the Recruitment Of Dblmentioning

confidence: 99%

See 1 more Smart Citation

Activated Ezrin Promotes Cell Migration through Recruitment of the GEF Dbl to Lipid Rafts and Preferential Downstream Activation of Cdc42

Prag

Parsons

Keppler

et al. 2007

MBoC

View full text Add to dashboard Cite

Establishment of polarized cell morphology is a critical factor for migration and requires precise spatial and temporal activation of the Rho GTPases. Here, we describe a novel role of the actin-binding ezrin/radixin/moesin (ERM)-protein ezrin to be involved in recruiting Cdc42, but not Rac1, to lipid raft microdomains, as well as the subsequent activation of this Rho GTPase and the downstream effector p21-activated kinase (PAK)1, as shown by fluorescence lifetime imaging microscopy. The establishment of a leading plasma membrane and the polarized morphology necessary for random migration are also dependent on ERM function and Cdc42 in motile breast carcinoma cells. Mechanistically, we show that the recruitment of the ERM-interacting Rho/Cdc42-specific guanine nucleotide exchange factor Dbl to the plasma membrane and to lipid raft microdomains requires the phosphorylated, active conformer of ezrin, which serves to tether the plasma membrane or its subdomains to the cytoskeleton. Together these data suggest a mechanism whereby precise spatial guanine nucleotide exchange of Cdc42 by Dbl is dependent on functional ERM proteins and is important for directional cell migration.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Expression Of N-ermad(e244k) Inhibits the Recruitment Of Dblmentioning

confidence: 99%

Activated Ezrin Promotes Cell Migration through Recruitment of the GEF Dbl to Lipid Rafts and Preferential Downstream Activation of Cdc42

Prag

Parsons

Keppler

et al. 2007

MBoC

View full text Add to dashboard Cite

show abstract

“…This association is thought to displace RhoGDI from Rho GTPases, allowing them to be activated by their specific guanine nucleotide exchange factors (GEFs; Takahashi et al, 1997). An association of ERM proteins with the exchange factor Dbl in vitro as well as in vivo has been reported (Takahashi et al, 1998;Lee et al, 2004;Vanni et al, 2004). In epithelial cells, an active form of ezrin has been shown to activate the small GTPase Rac1 with a concomitant disassembly of adherens junctions (Pujuguet et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Interaction of Ezrin with the Novel Guanine Nucleotide Exchange Factor PLEKHG6 Promotes RhoG-dependent Apical Cytoskeleton Rearrangements in Epithelial Cells

D'Angelo

Aresta

Blangy

et al. 2007

MBoC

View full text Add to dashboard Cite

The mechanisms underlying functional interactions between ERM (ezrin, radixin, moesin) proteins and Rho GTPases are not well understood. Here we characterized the interaction between ezrin and a novel Rho guanine nucleotide exchange factor, PLEKHG6. We show that ezrin recruits PLEKHG6 to the apical pole of epithelial cells where PLEKHG6 induces the formation of microvilli and membrane ruffles. These morphological changes are inhibited by dominant negative forms of RhoG. Indeed, we found that PLEKHG6 activates RhoG and to a much lesser extent Rac1. In addition we show that ezrin forms a complex with PLEKHG6 and RhoG. Furthermore, we detected a ternary complex between ezrin, PLEKHG6, and the RhoG effector ELMO. We demonstrate that PLEKHG6 and ezrin are both required in macropinocytosis. After down-regulation of either PLEKHG6 or ezrin expression, we observed an inhibition of dextran uptake in EGF-stimulated A431 cells. Altogether, our data indicate that ezrin allows the local activation of RhoG at the apical pole of epithelial cells by recruiting upstream and downstream regulators of RhoG and that both PLEKHG6 and ezrin are required for efficient macropinocytosis. INTRODUCTIONThe membrane-cytoskeleton linker ezrin is mainly expressed in epithelial cells where it associates to the apical actin-rich structures such as microvilli (Berryman et al., 1993(Berryman et al., , 1995. Recent genetic analyses revealed that ezrin is essential for the morphogenesis of epithelial cells (Fiévet et al., 2007). In ezrin Ϫ/Ϫ mice, morphological defects in the apical domain of intestinal and retinal pigment epithelial cells have been observed (Saotome et al., 2004;Bonilha et al., 2006). In parietal cells, ezrin knockdown impairs the formation of canalicular apical membrane, resulting in severe achlorhydria (Tamura et al., 2005).How ezrin participates in the assembly of the apical actinrich structures such as microvilli is still poorly understood. The association of ezrin and the highly related proteins radixin and moesin with the cortical actin cytoskeleton is strictly regulated. ERM (ezrin, radixin, moesin) proteins contain a conserved globular N-terminal domain, called the FERM domain (Four point one ezrin, radixin, moesin), involved in the binding to both phosphatidylinositol 4,5 bisphosphate (PIP 2 ; Barret et al., 2000) and plasma membrane proteins and a C-terminal F-actin-binding domain that resides in the last 34 amino acids (Turunen et al., 1994;Bretscher et al., 2002). In the cytoplasm, ERM proteins exist in a closed conformation because of an intramolecular interaction between the N-terminal domain and the last 100 amino acids called N-and C-ERMAD (ERM association domain), respectively . This intramolecular association masks the binding sites for plasma membrane proteins and F-actin. An activation step is required to disrupt this association that occurs through conformational changes induced by sequential binding to PIP 2 and phosphorylation of a conserved C-terminal threonine residue (T567 in ezrin; Matsui et al., 1998;Fié...

show abstract

“…17 ERM proteins can interact with regulators of Rho family GTPases and target them to specific cellular locations including the cell periphery. In particular, ezrin and radixin have been shown to bind to Dbl, 21,22 a RhoGEF which shows exchange activity for Rho and Cdc42. 31 Radixin is also able to bind to RhoGDI the Rho-GTPase inhibitory protein.…”

Section: Resultsmentioning

confidence: 99%

“…19 Ezrin radixin moesin (ERM) family proteins have previously been demonstrated to interact with components of the Rho GTPase signaling machinery, notably RhoGDI 20 and the GDP/GTP exchange factor (GEF) for Cdc42 and Rho: Dbl. 21,22 An interaction between dystroglycan, ezrin and regulatory elements of the Rho GTPase signaling pathway could explain the actions of dystroglycan on filopodia formation. We have therefore examined whether dystroglycan can target local Cdc42 activation and filopodia formation through the recruitment of an ezrin-Dbl complex.…”

Section: Introductionmentioning

confidence: 99%

Recruitment of Dbl by Ezrin and Dystroglycan Drives Membrane Proximal Cdc42 Activation and Filopodia Formation

Batchelor¹,

Higginson²,

Chen³

et al. 2007

Cell Cycle

Self Cite

View full text Add to dashboard Cite

ACKnoWLEdgEmEntSWe are grateful to the following for supplies of antisera or plasmids, Art Alberts, P. Aspenstrom, Louise Anderson, Francis Barr and Sam Crouch, and to Kathryn Ayscough for comments on the manuscript. The work was funded by an MRC Career Establishment Grant to S.J.W., J.R.H. was in receipt of a BBSRC studentship and A.E. was supported by grants from the Italian Association for Cancer Research, Compagnia S. Paolo, and Ministero della Salute. ABStRACtDystroglycan is an essential laminin binding cell adhesion molecule, which is also an adaptor for several SH2 domain-containing signaling molecules and as a scaffold for the ERK-MAP kinase cascade. Loss of dystroglycan function is implicated in muscular dystrophies and the aetiology of epithelial cancers. We have previously demonstrated a role for dystroglycan and ezrin in the formation of filopodia structures. Here we demonstrate the existence of a dystroglycan:ezrin:Dbl complex that is targeted to the membrane by dystroglycan where it drives local Cdc42 activation and the formation of filopodia. Deletion of an ezrin binding site in dystroglycan prevented the association with ezrin and Dbl and the formation of filopodia. Furthermore, expression of the dystroglycan cytoplasmic domain alone had a dominant-negative effect on filopodia formation and Cdc42 activation by sequestering ezrin and Dbl away from the membrane. Depletion of dystroglycan inhibited Cdc42-induced filopodia formation. For the first time we also demonstrate co-localization of Cdc42 and dystroglycan at the tips of dynamic filopodia.

show abstract

Phosphorylation-independent membrane relocalization of ezrin following association with Dbl in vivo

Cited by 21 publications

References 33 publications

Activated Ezrin Promotes Cell Migration through Recruitment of the GEF Dbl to Lipid Rafts and Preferential Downstream Activation of Cdc42

Activated Ezrin Promotes Cell Migration through Recruitment of the GEF Dbl to Lipid Rafts and Preferential Downstream Activation of Cdc42

Interaction of Ezrin with the Novel Guanine Nucleotide Exchange Factor PLEKHG6 Promotes RhoG-dependent Apical Cytoskeleton Rearrangements in Epithelial Cells

Recruitment of Dbl by Ezrin and Dystroglycan Drives Membrane Proximal Cdc42 Activation and Filopodia Formation

Contact Info

Product

Resources

About