scholarly journals PPM1F controls integrin activity via a conserved phospho-switch

2020 ◽  
Vol 219 (12) ◽  
Author(s):  
Tanja M. Grimm ◽  
Nina I. Dierdorf ◽  
Karin Betz ◽  
Christoph Paone ◽  
Christof R. Hauck
Keyword(s):  
Cell Adhesion ◽  
Cell Lines ◽  
Cytoplasmic Tail ◽  
Cytoplasmic Domain ◽  
Genetic Screen ◽  
Tissue Homeostasis ◽  
Integrin Β1 ◽  
Gain Of Function ◽  
Novel Target ◽  
Embryonic Death

Control of integrin activity is vital during development and tissue homeostasis, while derailment of integrin function contributes to pathophysiological processes. Phosphorylation of a conserved threonine motif (T788/T789) in the integrin β cytoplasmic domain increases integrin activity. Here, we report that T788/T789 functions as a phospho-switch, which determines the association with either talin and kindlin-2, the major integrin activators, or filaminA, an integrin activity suppressor. A genetic screen identifies the phosphatase PPM1F as the critical enzyme, which selectively and directly dephosphorylates the T788/T789 motif. PPM1F-deficient cell lines show constitutive integrin phosphorylation, exaggerated talin binding, increased integrin activity, and enhanced cell adhesion. These gain-of-function phenotypes are reverted by reexpression of active PPM1F, but not a phosphatase-dead mutant. Disruption of the ppm1f gene in mice results in early embryonic death at day E10.5. Together, PPM1F controls the T788/T789 phospho-switch in the integrin β1 cytoplasmic tail and constitutes a novel target to modulate integrin activity.

scholarly journals Elucidating the expression and function of Numbl during cell adhesion-mediated drug resistance (CAM-DR) in multiple myeloma (MM)

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Yuejiao Huang ◽  
Xianting Huang ◽  
Chun Cheng ◽  
Xiaohong Xu ◽  
Hong Liu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Drug Resistance ◽  
Cell Adhesion ◽  
Cell Lines ◽  
Molecular Mechanisms ◽  
Clinical Problem ◽  
Integrin Β1 ◽  
Cell Viability Assay ◽  
Adhesion Model

Abstract Background Cell adhesion-mediated drug resistance (CAM-DR) is a major clinical problem that prevents successful treatment of multiple myeloma (MM). In particular, the expression levels of integrin β1 and its sub-cellular distribution (internalization and trafficking) are strongly associated with CAM-DR development. Methods Development of an adhesion model of established MM cell lines and detection of Numbl and Integrinβ1 expression by Western Blot analysis. The interaction between Numbl and Integrinβ1 was assessed by a co-immunoprecipitation (CO-IP) method. Calcein AM assay was performed to investigate the levels of cell adhesion. Finally, the extent of CAM-DR in myeloma cells was measured using cell viability assay and flow cytometry analysis. Results Our preliminary date suggest that Numbl is differentially expressed in a cell adhesion model of MM cell lines. In addition to binding to the phosphotyrosine-binding (PTB) domain, the carboxyl terminal of Numbl can also interact with integrin β1 to regulate the cell cycle by activating the pro-survival PI3K/AKT signaling pathway. This study intends to verify and elucidate the interaction between Numbl and integrin β1 and its functional outcome on CAM-DR. We have designed and developed a CAM-DR model using MM cells coated with either fibronectin or bone marrow stromal cells. We assessed whether Numbl influences cell-cycle progression and whether it, in turn, contributes to activation of PI3K/AKT signal pathway through the adjustment of its carboxyl end. Finally, we showed that the interaction of Numbl with integrin β1 promotes the formation of CAM-DR in MM cells. Conclusions Our findings elucidated the specific molecular mechanisms of CAM-DR induction and confirmed that Numbl is crucial for the development of CAM-DR in MM cells.

scholarly journals Two Cell Adhesion Molecules, Nectin and Cadherin, Interact through Their Cytoplasmic Domain–Associated Proteins

2000 ◽  
Vol 150 (5) ◽  
pp. 1161-1176 ◽  
Author(s):  
Kouichi Tachibana ◽  
Hiroyuki Nakanishi ◽  
Kenji Mandai ◽  
Kumi Ozaki ◽  
Wataru Ikeda ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Lines ◽  
Cell Adhesion Molecules ◽  
Cytoplasmic Domain ◽  
Adhesion Sites ◽  
Adhesion System ◽  
Associated Proteins ◽  
Mechanism Of Interaction ◽  
E Cadherin ◽  
Cell Cell

We have found a new cell–cell adhesion system at cadherin-based cell–cell adherens junctions (AJs) consisting of at least nectin and l-afadin. Nectin is a Ca2+-independent homophilic immunoglobulin-like adhesion molecule, and l-afadin is an actin filament-binding protein that connects the cytoplasmic region of nectin to the actin cytoskeleton. Both the trans-interaction of nectin and the interaction of nectin with l-afadin are necessary for their colocalization with E-cadherin and catenins at AJs. Here, we examined the mechanism of interaction between these two cell–cell adhesion systems at AJs by the use of α-catenin–deficient F9 cell lines and cadherin-deficient L cell lines stably expressing their various components. We showed here that nectin and E-cadherin were colocalized through l-afadin and the COOH-terminal half of α-catenin at AJs. Nectin trans-interacted independently of E-cadherin, and the complex of E-cadherin and α- and β-catenins was recruited to nectin-based cell–cell adhesion sites through l-afadin without the trans-interaction of E-cadherin. Our results indicate that nectin and cadherin interact through their cytoplasmic domain–associated proteins and suggest that these two cell–cell adhesion systems cooperatively organize cell–cell AJs.

scholarly journals Cytoplasmic Tail Regulates the Intercellular Adhesion Function of the Epithelial Cell Adhesion Molecule

1998 ◽  
Vol 18 (8) ◽  
pp. 4833-4843 ◽  
Author(s):  
Maarten Balzar ◽  
Hellen A. M. Bakker ◽  
Inge H. Briaire-de-Bruijn ◽  
Gert Jan Fleuren ◽  
Sven O. Warnaar ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Solid Phase ◽  
Cytoplasmic Tail ◽  
Cytoplasmic Domain ◽  
Specific Cell ◽  
Actin Microfilaments ◽  
Intercellular Adhesions ◽  
Cell Cell

ABSTRACT Ep-CAM, an epithelium-specific cell-cell adhesion molecule (CAM) not structurally related to the major families of CAMs, contains a cytoplasmic domain of 26 amino acids. The chemical disruption of the actin microfilaments, but not of the microtubuli or intermediate filaments, affected the localization of Ep-CAM at the cell-cell boundaries, suggesting that the molecule interacts with the actin-based cytoskeleton. Mutated forms of Ep-CAM were generated with the cytoplasmic domain truncated at various lengths. All of the mutants were transported to the cell surface in the transfectants; however, the mutant lacking the complete cytoplasmic domain was not able to localize to the cell-cell boundaries, in contrast to mutants with partial deletions. Both the disruption of the actin microfilaments and a complete truncation of the cytoplasmic tail strongly affected the ability of Ep-CAM to mediate aggregation of L cells. The capability of direct aggregation was reduced for the partially truncated mutants but remained cytochalasin D sensitive. The tail truncation did not affect the ability of the transfectants to adhere to solid-phase-adsorbed Ep-CAM, suggesting that the ability to form stable adhesions and not the ligand specificity of the molecule was affected by the truncation. The formation of intercellular adhesions mediated by Ep-CAM induced a redistribution to the cell-cell boundaries of α-actinin, but not of vinculin, talin, filamin, spectrin, or catenins. Coprecipitation demonstrated direct association of Ep-CAM with α-actinin. Binding of α-actinin to purified mutated and wild-type Ep-CAMs and to peptides representing different domains of the cytoplasmic tail of Ep-CAM demonstrates two binding sites for α-actinin at positions 289 to 296 and 304 to 314 of the amino acid sequence. The results demonstrate that the cytoplasmic domain of Ep-CAM regulates the adhesion function of the molecule through interaction with the actin cytoskeleton via α-actinin.

scholarly journals Interchangeable alpha chain cytoplasmic domains play a positive role in control of cell adhesion mediated by VLA-4, a beta 1 integrin.

1993 ◽  
Vol 178 (2) ◽  
pp. 649-660 ◽  
Author(s):  
P D Kassner ◽  
M E Hemler
Keyword(s):  
Cell Adhesion ◽  
Cell Lines ◽  
Deletion Mutant ◽  
K562 Cells ◽  
Cytoplasmic Domain ◽  
Wild Type ◽  
Cytoplasmic Domains ◽  
Positive Role ◽  
Alpha Chain ◽  
Poor Adhesion

Integrins can exist in a range of functional states, depending on the cell type and its state of activation. Although the mechanism that controls activity is unknown, it has been suggested that for some integrins, alpha chain cytoplasmic domains may exert either a negative effect or no effect on adhesion function. To address this issue for VLA-4 (an alpha 4 beta 1 heterodimer), we constructed an alpha 4 cytoplasmic deletion mutant and chimeric alpha chains composed of the extracellular domains of alpha 4 and the cytoplasmic domains of alpha 2, alpha 4, or alpha 5. Upon stable transfection of wild-type alpha 4, VLA-4 heterodimer was obtained that mediated (a) poor adhesion to CS1 peptide, fibronectin, or vascular cell adhesion molecule 1 (VCAM-1) (in K562 cells); (b) poor adhesion to CS1 peptide but moderate adhesion to VCAM-1 (in MIP101 cells); and (c) moderate adhesion to both CS1 peptide and VCAM-1 (in PMWK cells). Chimeric alpha 4 constructs and wild-type alpha 4 yielded similar results in these cell lines. In contrast, truncation of the alpha 4 cytoplasmic domain (after the conserved GFFKR motif) caused an almost complete loss of adhesive activity in all three cell lines. Thus, several interchangeable alpha chain cytoplasmic domains play a fundamentally positive role in determining the state of constitutive activity for VLA-4. The alpha chain cytoplasmic domain is also required for agonist-stimulated adhesion, since phorbol ester stimulated the cell adhesion mediated by wild-type and chimeric alpha chains, but not by the cytoplasmic deletion mutant. The inactivity of both wild-type VLA-4 (in K562 cells), and truncated VLA-4 (in all three cell lines) was overcome by the addition of a stimulatory anti-beta 1 monoclonal antibody. Thus, the alpha cytoplasmic domain-dependent cellular mechanism controlling both constitutive and agonist-stimulated VLA-4 activity could be bypassed by external manipulation of the integrin.

scholarly journals Circ_0003266 sponges miR-503-5p to suppress colorectal cancer progression via regulating PDCD4 expression

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Caihong Wen ◽  
Xiaoqing Feng ◽  
Honggang Yuan ◽  
Yong Gong ◽  
Guangsheng Wang
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Cell Lines ◽  
Cancer Progression ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Pdcd4 Expression ◽  
Novel Target

Abstract Background Circular RNAs (circRNAs) feature prominently in tumor progression. However, the biological function and molecular mechanism of circ_0003266 in colorectal cancer (CRC) require further investigation. Methods Circ_0003266 expression in 46 pairs CRC tissues / adjacent tissues, and CRC cell lines was detected by quantitative real-time polymerase chain reaction (qRT-PCR); after circ_0003266 was overexpressed or knocked down in CRC cells, cell proliferation, apoptosis, migration, and invasion were evaluated by the cell counting kit-8 (CCK-8), flow cytometry, and Transwell assays, respectively; the interaction among circ_0003266, miR-503-5p, and programmed cell death 4 (PDCD4) was confirmed using bioinformatics analysis and dual-luciferase reporter assay; PDCD4 protein expression in CRC cells was quantified using Western blot. Results Circ_0003266 was significantly lowly expressed in CRC tissues and cell lines. Circ_0003266 overexpression markedly repressed CRC cell proliferation, migration, and invasion, and accelerated the cell apoptosis, but its overexpression promoted the malignant phenotypes of CRC cells. PDCD4 was a direct target of miR-503-5p and circ_0003266 promoted PDCD4 expression by competitively sponging miR-503-5p. Conclusion Circ_0003266 suppresses the CRC progression via sponging miR-503-5p and regulating PDCD4 expressions, which suggests that circ_0003266 may serve as a novel target for the treatment of CRC.

scholarly journals Dynamic changes in the osteoclast cytoskeleton in response to growth factors and cell attachment are controlled by β3 integrin

2003 ◽  
Vol 162 (3) ◽  
pp. 499-509 ◽  
Author(s):  
Roberta Faccio ◽  
Deborah V. Novack ◽  
Alberta Zallone ◽  
F. Patrick Ross ◽  
Steven L. Teitelbaum
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Cell Attachment ◽  
Cytoplasmic Tail ◽  
Cytoplasmic Domain ◽  
Small Gtpases ◽  
Cytoskeletal Reorganization ◽  
Integrin Activation ◽  
Intracellular Signals ◽  
Β3 Integrin

The β3 integrin cytoplasmic domain, and specifically S752, is critical for integrin localization and osteoclast (OC) function. Because growth factors such as macrophage colony–stimulating factor and hepatocyte growth factor affect integrin activation and function via inside-out signaling, a process requiring the β integrin cytoplasmic tail, we examined the effect of these growth factors on OC precursors. To this end, we retrovirally expressed various β3 integrins with cytoplasmic tail mutations in β3-deficient OC precursors. We find that S752 in the β3 cytoplasmic tail is required for growth factor–induced integrin activation, cytoskeletal reorganization, and membrane protrusion, thereby affecting OC adhesion, migration, and bone resorption. The small GTPases Rho and Rac mediate cytoskeletal reorganization, and activation of each is defective in OC precursors lacking a functional β3 subunit. Activation of the upstream mediators c-Src and c-Cbl is also dependent on β3. Interestingly, although the FAK-related kinase Pyk2 interacts with c-Src and c-Cbl, its activation is not disrupted in the absence of functional β3. Instead, its activation is dependent upon intracellular calcium, and on the β2 integrin. Thus, the β3 cytoplasmic domain is responsible for activation of specific intracellular signals leading to cytoskeletal reorganization critical for OC function.

Invasive behaviour of glioblastoma cell lines is associated with altered organisation of the cadherin-catenin adhesion system

2002 ◽  
Vol 115 (16) ◽  
pp. 3331-3340 ◽  
Author(s):  
Carla Perego ◽  
Cristina Vanoni ◽  
Silvia Massari ◽  
Andrea Raimondi ◽  
Sandra Pola ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Lines ◽  
Protein A ◽  
Cell Types ◽  
Glioblastoma Cell ◽  
Migration Assay ◽  
Adhesion System ◽  
Pdz Protein ◽  
Glioblastoma Cell Lines ◽  
Cell Cell

As little is known about the role of cadherin-mediated cell-cell adhesion in astrocytes and its alteration in migrating and invasive glioblastomas, we investigated its molecular composition and organisation in primary cultured astrocytes and the T98G and U373MG glioblastoma cell lines. Biochemical and morphological analysis indicated that all three cell types express all of the structural components of the adhesion system, including the LIN-7 PDZ protein,a novel component involved in the organisation of the junctional domain in epithelia and neurons. However, only the astrocytes and T98G cells generated and maintained mature adhesive junctional domains to which LIN-7 was recruited. Alterations in the junctional domain of U373MG cells were associated with higher motility in a poly-L-lysine migration assay. When the T98G cells were cultured on Matrigel matrix, they acquired invasive properties but, despite unchanged cadherin adhesion system protein levels, the invasive T98G cell-cell contacts failed to accumulate LIN-7 and failed to mature. These results identify the LIN-7 PDZ protein as a marker of cell adhesion maturity and cell invasion and indicate that instability and disorganisation of cadherin-mediated junctions rather than reduced expression of cadherin-catenin system components are required to promote migration and invasiveness in glioblastoma cell lines.

scholarly journals Immediate early response protein 2 regulates hepatocellular carcinoma cell adhesion and motility via integrin β1-mediated signaling pathway

2016 ◽  
Vol 37 (1) ◽  
pp. 259-272 ◽  
Author(s):  
Zhengxin Xu ◽  
Lei Zhu ◽  
Wenjuan Wu ◽  
Yuexia Liao ◽  
Weicheng Zhang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Adhesion ◽  
Signaling Pathway ◽  
Carcinoma Cell ◽  
Early Response ◽  
Immediate Early ◽  
Integrin Β1 ◽  
Hepatocellular Carcinoma Cell

scholarly journals Human T-Cell Leukemia Virus Type 1 Envelope-Mediated Syncytium Formation Can Be Activated in Resistant Mammalian Cell Lines by a Carboxy-Terminal Truncation of the Envelope Cytoplasmic Domain

2003 ◽  
Vol 77 (2) ◽  
pp. 963-969 ◽  
Author(s):  
Felix J. Kim ◽  
Nicolas Manel ◽  
Yvan Boublik ◽  
Jean-Luc Battini ◽  
Marc Sitbon
Keyword(s):  
Amino Acids ◽  
Cell Lines ◽  
Leukemia Virus ◽  
Syncytium Formation ◽  
Cytoplasmic Domain ◽  
Cell Leukemia ◽  
Cell Infection ◽  
Human T Cell ◽  
T Cell Leukemia Virus ◽  
Carboxy Terminal

ABSTRACT Human T-cell leukemia virus (HTLV) envelope (Env) glycoproteins induce fusion, leading to rampant syncytium formation in a broad range of cell lines. Here, we identified murine, hamster, canine, and porcine cell lines that are resistant to HTLV-1 Env-induced syncytium formation. This resistance was not due to the absence of functional receptors for HTLV Env, as these cells were susceptible to infection with HTLV Env-pseudotyped virions. As murine leukemia virus (MLV) Env and HTLV Env present close structural homologies (F. J. Kim, I. Seiliez, C. Denesvre, D. Lavillette, F. L. Cosset, and M. Sitbon, J. Biol. Chem. 275:23417-23420, 2000), and because activation of syncytium formation by MLV Env generally requires cleavage of the R peptide in the cytoplasmic domain of the Env transmembrane (TM) component, we assessed whether truncation of the cytoplasmic domain of HTLV Env would alleviate this resistance. Indeed, in all resistant cell lines, truncation of the last 8 amino acids of the HTLV Env cytoplasmic domain (HdC8) was sufficient to overcome resistance to HTLV Env-induced syncytium formation. Furthermore, HdC8-mediated cell-to-cell infection titers varied according to the target cell lines and could be significantly higher than that observed with HTLV Env on HeLa cells. These data indicate that a determinant located within the 8 carboxy-terminal cytoplasmic amino acids of TM plays a distinct role in HTLV Env-mediated cell-to-cell infection and syncytium formation.

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