scholarly journals The inositol 5-phosphatase SHIP2 is an effector of RhoA and is involved in cell polarity and migration

2012 ◽  
Vol 23 (13) ◽  
pp. 2593-2604 ◽  
Author(s):  
Katsuhiro Kato ◽  
Tsubasa Yazawa ◽  
Kentaro Taki ◽  
Kazutaka Mori ◽  
Shujie Wang ◽  
...  
Keyword(s):  
Small Gtpases ◽  
Cell Polarization ◽  
Dependent Manner ◽  
Wild Type ◽  
Functional Interaction ◽  
Src Homology 2 ◽  
Motile Cells ◽  
Lipid Turnover ◽  
Src Homology ◽  
And Migration

Cell migration is essential for various physiological and pathological processes. Polarization in motile cells requires the coordination of several key signaling molecules, including RhoA small GTPases and phosphoinositides. Although RhoA participates in a front–rear polarization in migrating cells, little is known about the functional interaction between RhoA and lipid turnover. We find here that src-homology 2–containing inositol-5-phosphatase 2 (SHIP2) interacts with RhoA in a GTP-dependent manner. The association between SHIP2 and RhoA is observed in spreading and migrating U251 glioma cells. The depletion of SHIP2 attenuates cell polarization and migration, which is rescued by wild-type SHIP2 but not by a mutant defective in RhoA binding. In addition, the depletion of SHIP2 impairs the proper localization of phosphatidylinositol 3,4,5-trisphosphate, which is not restored by a mutant defective in RhoA binding. These results suggest that RhoA associates with SHIP2 to regulate cell polarization and migration.

scholarly journals Suppressive Role of Bam32/DAPP1 in Chemokine-Induced Neutrophil Recruitment

2021 ◽  
Vol 22 (4) ◽  
pp. 1825
Author(s):  
Li Hao ◽  
Aaron J. Marshall ◽  
Lixin Liu
Keyword(s):  
Small Gtpases ◽  
Neutrophil Recruitment ◽  
Neutrophil Chemotaxis ◽  
Wild Type ◽  
Adaptor Molecule ◽  
Geranylgeranyltransferase I ◽  
And Migration ◽  
Rap1 Activation

Bam32 (B cell adaptor molecule of 32 kDa) functions in the immune responses of various leukocytes. However, the role of neutrophil Bam32 in inflammation is entirely unknown. Here, we determined the role of Bam32 in chemokine CXCL2-induced neutrophil chemotaxis in three mouse models of neutrophil recruitment. By using intravital microscopy in the mouse cremaster muscle, we found that transmigrated neutrophil number, neutrophil chemotaxis velocity, and total neutrophil chemotaxis distance were increased in Bam32−/− mice when compared with wild-type (WT) mice. In CXCL2-induced mouse peritonitis, the total emigrated neutrophils were increased in Bam32−/− mice at 2 but not 4 h. The CXCL2-induced chemotaxis distance and migration velocity of isolated Bam32−/− neutrophils in vitro were increased. We examined the activation of small GTPases Rac1, Rac2, and Rap1; the levels of phospho-Akt2 and total Akt2; and their crosstalk with Bam32 in neutrophils. The deficiency of Bam32 suppressed Rap1 activation without changing the activation of Rac1 and Rac2. The pharmacological inhibition of Rap1 by geranylgeranyltransferase I inhibitor (GGTI298) increased WT neutrophil chemotaxis. In addition, the deficiency of Bam32, as well as the inhibition of Rap1 activation, increased the levels of CXCL2-induced Akt1/2 phosphorylation at Thr308/309 in neutrophils. The inhibition of Akt by SH-5 attenuated CXCL2-induced adhesion and emigration in Bam32−/− mice. Together, our results reveal that Bam32 has a suppressive role in chemokine-induced neutrophil chemotaxis by regulating Rap1 activation and that this role of Bam32 in chemokine-induced neutrophil recruitment relies on the activation of PI3K effector Akt.

SRC-homology 2 domain-containing phosphatase 2 (SHP2) in epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (LUAD).

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 9540-9540
Author(s):  
Rafael Rosell ◽  
Masaoki Ito ◽  
Jordi Codony-Servat ◽  
Ana Giménez-Capitán ◽  
Mireia Serra-Mitjans ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Mrna Expression ◽  
Mrna Levels ◽  
Wild Type ◽  
Src Homology 2 ◽  
Src Homology ◽  
Epidermal Growth ◽  
Src Homology 2 Domain ◽  
Egfr Mutant

9540 Background: Epidermal growth factor (EGFR)-mutant lung adenocarcinomas (LUADs) display impaired phosphorylation of extracellular signal-regulated kinase (ERK) and SRC-homology 2 domain-containing phosphatase 2 (SHP2) in comparison with EGFR wild-type LUADs. However, the function of SHP2 in early EGFR-mutant LUADs and EGFR wild-type LUADs has not been reported. We posit that SHP2 mRNA expression could be a predictive marker in resected EGFR-mutant LUADs versus EGFR wild-type patients (pts). Methods: We examined 267 resected LUADs from Japan and Spain. mRNA expression levels of AXL, MET, CDCP1, STAT3, YAP1 and SHP2 were analyzed by quantitative reverse transcriptase polymerase chain reaction (PCR). EGFR mutant cell lines were investigated for their activity of SHP2. Results: Among the 267 enrolled pts, 100 (37.3%) were EGFR-mutant LUADs. Five-year recurrence-free survival (RFS) and overall survival (OS) were lower for EGFR-mutant LUADs with high SHP2 mRNA levels (hazard ratio = 1.83 and 2.28, respectively. p = 0.03 and p = 0.04). However, SHP2 was not associated with RFS nor OS in the 167 wild-type EGFR LUADs. In EGFR-mutant cells, RMC-4550 (SHP2 inhibitor) plus erlotinib showed synergism via inhibition of AKT (S473) and ERK1/2 (T202/Y204). While erlotinib translocates SHP2 (Y542) into the nucleus, either RMC-4550 alone, or in combination with erlotinib, relocalizes SHP2 into the cytoplasm membrane, limiting AKT and ERK activation. Conclusions: High SHP2 mRNA is related to shorter RFS and OS in EGFR-mutant LUADs, but not in EGFR wild-type LUADs. The findings indicate that the addition of SHP2 inhibitors could improve adjuvant therapy in EGFR-mutant LUADs.

scholarly journals Structural Basis and Functional Consequence of Helicobacter pylori CagA Multimerization in Cells

2006 ◽  
Vol 281 (43) ◽  
pp. 32344-32352 ◽  
Author(s):  
Shumei Ren ◽  
Hideaki Higashi ◽  
Huaisheng Lu ◽  
Takeshi Azuma ◽  
Masanori Hatakeyama
Keyword(s):  
Helicobacter Pylori ◽  
Tyrosine Phosphorylation ◽  
Cell Shape ◽  
Host Cells ◽  
Structural Basis ◽  
Sequence Motif ◽  
Wild Type ◽  
Src Homology 2 ◽  
Src Homology ◽  
In Cells

Helicobacter pylori cagA-positive strains are associated with gastric adenocarcinoma. The cagA gene product CagA is delivered into gastric epithelial cells where it localizes to the plasma membrane and undergoes tyrosine phosphorylation at the EPIYA-repeat region, which contains the EPIYA-A segment, EPIYA-B segment, and Western CagA-specific EPIYA-C or East Asian CagA-specific EPIYA-D segment. In host cells, CagA specifically binds to and deregulates SHP-2 phosphatase via the tyrosine-phosphorylated EPIYA-C or EPIYA-D segment, thereby inducing an elongated cell shape known as the hummingbird phenotype. In this study, we found that CagA multimerizes in cells in a manner independent of its tyrosine phosphorylation. Using a series of CagA mutants, we identified a conserved amino acid sequence motif (FPLXRXXXVXDLSKVG), which mediates CagA multimerization, within the EPIYA-C segment as well as in a sequence that located immediately downstream of the EPIYA-C or EPIYA-D segment. We also found that a phosphorylation-resistant CagA, which multimerizes but cannot bind SHP-2, inhibits the wild-type CagA-SHP-2 complex formation and abolishes induction of the hummingbird phenotype. Thus, SHP-2 binds to a preformed and tyrosinephosphorylated CagA multimer via its two Src homology 2 domains. These results, in turn, indicate that CagA multimerization is a prerequisite for CagA-SHP-2 interaction and subsequent deregulation of SHP-2. The present work raises the possibility that inhibition of CagA multimerization abolishes pathophysiological activities of CagA that promote gastric carcinogenesis.

scholarly journals Pleiotropic Roles of Calmodulin in the Regulation of KRas and Rac1 GTPases: Functional Diversity in Health and Disease

2020 ◽  
Vol 21 (10) ◽  
pp. 3680 ◽  
Author(s):  
Francesc Tebar ◽  
Albert Chavero ◽  
Neus Agell ◽  
Albert Lu ◽  
Carles Rentero ◽  
...  
Keyword(s):  
Biological Response ◽  
Direct Interaction ◽  
Small Gtpases ◽  
Dependent Manner ◽  
Nucleotide Exchange ◽  
Calmodulin Binding ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Cellular Events ◽  
And Migration

Calmodulin is a ubiquitous signalling protein that controls many biological processes due to its capacity to interact and/or regulate a large number of cellular proteins and pathways, mostly in a Ca2+-dependent manner. This complex interactome of calmodulin can have pleiotropic molecular consequences, which over the years has made it often difficult to clearly define the contribution of calmodulin in the signal output of specific pathways and overall biological response. Most relevant for this review, the ability of calmodulin to influence the spatiotemporal signalling of several small GTPases, in particular KRas and Rac1, can modulate fundamental biological outcomes such as proliferation and migration. First, direct interaction of calmodulin with these GTPases can alter their subcellular localization and activation state, induce post-translational modifications as well as their ability to interact with effectors. Second, through interaction with a set of calmodulin binding proteins (CaMBPs), calmodulin can control the capacity of several guanine nucleotide exchange factors (GEFs) to promote the switch of inactive KRas and Rac1 to an active conformation. Moreover, Rac1 is also an effector of KRas and both proteins are interconnected as highlighted by the requirement for Rac1 activation in KRas-driven tumourigenesis. In this review, we attempt to summarize the multiple layers how calmodulin can regulate KRas and Rac1 GTPases in a variety of cellular events, with biological consequences and potential for therapeutic opportunities in disease settings, such as cancer.

scholarly journals Lyn and PECAM-1 function as interdependent inhibitors of platelet aggregation

Blood ◽  
2011 ◽  
Vol 117 (14) ◽  
pp. 3903-3906 ◽  
Author(s):  
Zhangyin Ming ◽  
Yu Hu ◽  
Jizhou Xiang ◽  
Peter Polewski ◽  
Peter J. Newman ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Dependent Manner ◽  
Glycoprotein Vi ◽  
Src Homology 2 ◽  
Platelet Endothelial Cell Adhesion ◽  
Src Homology ◽  
Src Homology 2 Domain ◽  
Cell Adhesion Molecule 1 ◽  
Collagen Receptor ◽  
Deficient Mice

Abstract Inhibition of platelet responsiveness is important to control pathologic thrombus formation. Platelet–endothelial cell adhesion molecule-1 (PECAM-1) and the Src family kinase Lyn inhibit platelet activation by the glycoprotein VI (GPVI) collagen receptor; however, it is not known whether PECAM-1 and Lyn function in the same or different inhibitory pathways. In these studies, we found that, relative to wild-type platelets, platelets derived from PECAM-1–deficient, Lyn-deficient, or PECAM-1/Lyn double-deficient mice were equally hyperresponsive to stimulation with a GPVI-specific agonist, indicating that PECAM-1 and Lyn participate in the same inhibitory pathway. Lyn was required for PECAM-1 tyrosine phosphorylation and subsequent binding of the Src homology 2 domain–containing phosphatase-2, SHP-2. These results support a model in which PECAM-1/SHP-2 complexes, formed in a Lyn-dependent manner, suppress GPVI signaling.

scholarly journals Role of P120 Ras-Gap in Directed Cell Movement

2000 ◽  
Vol 149 (2) ◽  
pp. 457-470 ◽  
Author(s):  
Sarang V. Kulkarni ◽  
Gerald Gish ◽  
Peter van der Geer ◽  
Mark Henkemeyer ◽  
Tony Pawson
Keyword(s):  
Cell Polarity ◽  
Cell Movement ◽  
Focal Adhesions ◽  
Cell Polarization ◽  
Actin Stress Fiber ◽  
Dependent Manner ◽  
Directional Movement ◽  
Complete Cell ◽  
And Migration

We have used cell lines deficient in p120 Ras GTPase activating protein (Ras-GAP) to investigate the roles of Ras-GAP and the associated p190 Rho-GAP (p190) in cell polarity and cell migration. Cell wounding assays showed that Ras-GAP–deficient cells were incapable of establishing complete cell polarity and migration into the wound. Stimulation of mutant cells with growth factor rescued defects in cell spreading, Golgi apparatus fragmentation, and polarized vesicular transport and partially rescued migration in a Ras-dependent manner. However, for directional movement, the turnover of stress fibers and focal adhesions to produce an elongate morphology was dependent on the constitutive association between Ras-GAP and p190, independent of Ras regulation. Disruption of the phosphotyrosine-mediated Ras-GAP/p190 complex by microinjecting synthetic peptides derived from p190 sequences in wild-type cells caused a suppression of actin filament reorientation and migration. From these observations we suggest that although Ras-GAP is not directly required for motility per se, it is important for cell polarization by regulating actin stress fiber and focal adhesion reorientation when complexed with 190. This observation suggests a specific function for Ras-GAP separate from Ras regulation in cell motility.

Lck is required for stromal cell–derived factor 1α (CXCL12)–induced lymphoid cell chemotaxis

Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4318-4325 ◽  
Author(s):  
Marit Inngjerdingen ◽  
Knut Martin Torgersen ◽  
Azzam A. Maghazachi
Keyword(s):  
Nk Cells ◽  
Cell Line ◽  
Tyrosine Kinases ◽  
Stromal Cell ◽  
Wild Type ◽  
Src Homology 2 ◽  
Jurkat T Cell ◽  
Src Homology ◽  
Syk Inhibitor ◽  
Stromal Cell Derived Factor

Stromal cell–derived factor 1α (CXCL12) induces chemotaxis of lymphocytes through its receptor CXCR4. We examined the role of nonreceptor tyrosine kinases in CXCL12-induced chemotaxis of T cells and natural killer (NK) cells. Damnacanthal, a specific Lck inhibitor, but not the Syk inhibitor piceatannol, inhibited CXCL12-induced chemotaxis of both lymphocyte subsets. Similarly, damnacanthal was shown to inhibit CXCL12-induced chemotaxis of the Jurkat T-cell line. Stimulating T and NK cells with CXCL12 increased both the tyrosine phosphorylation and the kinase activity of Lck. A direct involvement of Lck in CXCL12-induced chemotaxis was demonstrated in the Lck-deficient Jurkat-derived cell line JCaM1.6. Although JCaM1.6 cells express CXCR4, no significant migration was detected after CXCL12 stimulation. Reconstitution with wild-type Lck restored both CXCL12-induced chemotaxis and Lck activation. Furthermore, cotransfection of wild-type Lck with C-terminal Src kinase (Csk) into JCaM1.6 failed to restore the chemotactic response induced by CXCL12. Finally, by targeting critical residues in the Src homology–2 (SH2) or SH3 domains of Lck, we observed that the SH3 domain is important for the function of Lck in CXCL12-mediated chemotaxis. Together, these results suggest a role for Lck in CXCL12-induced signaling pathways leading to lymphocyte chemotaxis.

scholarly journals Glycoprotein VI/Fc receptor γ chain-independent tyrosine phosphorylation and activation of murine platelets by collagen

2004 ◽  
Vol 383 (3) ◽  
pp. 581-588 ◽  
Author(s):  
Gavin E. JARVIS ◽  
Denise BEST ◽  
Steve P. WATSON
Keyword(s):  
Tyrosine Phosphorylation ◽  
Chain Complex ◽  
Fc Receptor ◽  
Adapter Protein ◽  
Wild Type ◽  
Functional Responses ◽  
Glycoprotein Vi ◽  
Src Homology 2 ◽  
Src Homology ◽  
Collagen Receptor

We have investigated the ability of collagen to induce signalling and functional responses in suspensions of murine platelets deficient in the FcRγ (Fc receptor γ) chain, which lack the collagen receptor GPVI (glycoprotein VI). In the absence of the FcRγ chain, collagen induced a unique pattern of tyrosine phosphorylation which was potentiated by the thromboxane analogue U46619. Immunoprecipitation studies indicated that neither collagen alone nor the combination of collagen plus U46619 induced phosphorylation of the GPVI-regulated proteins Syk and SLP-76 (Src homology 2-containing leucocyte protein of 76 kDa). A low level of tyrosine phosphorylation of phospholipase Cγ2 was observed, which was increased in the presence of U46619, although the degree of phosphorylation remained well below that observed in wild-type platelets (∼10%). By contrast, collagen-induced phosphorylation of the adapter ADAP (adhesion- and degranulation-promoting adapter protein) was substantially potentiated by U46619 to levels equivalent to those observed in wild-type platelets. Collagen plus U46619 also induced significant phosphorylation of FAK (focal adhesion kinase). The functional significance of collagen-induced non-GPVI signals was highlighted by the ability of U46619 and collagen to induce the secretion of ATP in FcRγ chain-deficient platelets, even though neither agonist was effective alone. Protein tyrosine phosphorylation and the release of ATP were abolished by the anti-(α2 integrin) antibodies Ha1/29 and HMα2, but not by blockade of αIIbβ3. These results illustrate a novel mechanism of platelet activation by collagen which is independent of the GPVI–FcRγ chain complex, and is facilitated by binding of collagen to integrin α2β1.

scholarly journals Lef1 regulates caveolin expression and caveolin dependent endocytosis, a process necessary for Wnt5a/Ror2 signaling during Xenopus gastrulation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katharina Puzik ◽  
Veronika Tonnier ◽  
Isabell Opper ◽  
Antonia Eckert ◽  
Lu Zhou ◽  
...  
Keyword(s):  
Target Genes ◽  
Cell Polarization ◽  
Dependent Manner ◽  
Convergent Extension ◽  
Receptor Complexes ◽  
Basolateral Side ◽  
Canonical Pathways ◽  
And Migration ◽  
Receptor Clusters ◽  
Canonical Wnt

Abstract The activation of distinct branches of the Wnt signaling network is essential for regulating early vertebrate development. Activation of the canonical Wnt/β-catenin pathway stimulates expression of β-catenin-Lef/Tcf regulated Wnt target genes and a regulatory network giving rise to the formation of the Spemann organizer. Non-canonical pathways, by contrast, mainly regulate cell polarization and migration, in particular convergent extension movements of the trunk mesoderm during gastrulation. By transcriptome analyses, we found caveolin1, caveolin3 and cavin1 to be regulated by Lef1 in the involuting mesoderm of Xenopus embryos at gastrula stages. We show that caveolins and caveolin dependent endocytosis are necessary for proper gastrulation, most likely by interfering with Wnt5a/Ror2 signaling. Wnt5a regulates the subcellular localization of receptor complexes, including Ror2 homodimers, Ror2/Fzd7 and Ror2/dsh heterodimers in an endocytosis dependent manner. Live-cell imaging revealed endocytosis of Ror2/caveolin1 complexes. In Xenopus explants, in the presence of Wnt5a, these receptor clusters remain stable exclusively at the basolateral side, suggesting that endocytosis of non-canonical Wnt/receptor complexes preferentially takes place at the apical membrane. In support of this blocking endocytosis with inhibitors prevents the effects of Wnt5a. Thus, target genes of Lef1 interfere with Wnt5a/Ror2 signaling to coordinate gastrulation movements.

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