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Gosain H, Busch KB. TC10 differently controls the dynamics of Exo70 in growth cones of cortical and hippocampal neurons. BIOPHYSICAL REPORTS 2024; 4:100186. [PMID: 39521348 PMCID: PMC11617994 DOI: 10.1016/j.bpr.2024.100186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 10/28/2024] [Accepted: 11/05/2024] [Indexed: 11/16/2024]
Abstract
The exocyst is an octameric protein complex that acts as a tether for GOLGI-derived vesicles at the plasma membrane during exocytosis. It is involved in membrane expansion during axonal outgrowth. Exo70 is a major subunit of the exocyst complex and is controlled by TC10, a Rho family GTPase. How TC10 affects the dynamics of Exo70 at the plasma membrane is not well understood. There is also evidence that TC10 controls Exo70 dynamics differently in nonpolar cells and axons. To address this, we used super-resolution microscopy to study the spatially resolved effects of TC10 on Exo70 dynamics in HeLa cells and the growth cone of cortical and hippocampal neurons. We generated single-particle localization and trajectory maps and extracted mean square displacements, diffusion coefficients, and alpha coefficients to characterize Exo70 diffusion. We found that the diffusivity of Exo70 was different in nonpolar cells and the growth cone of neurons. TC10 stimulated the mobility of Exo70 in HeLa cells but decreased the diffusion of Exo70 in the growth cone of cortical neurons. In contrast to cortical neurons, TC10 overexpression did not affect the mobility of Exo70 in the axonal growth cone of hippocampal neurons. These data suggest that mainly exocyst tethering in cortical neurons was under the control of TC10.
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Affiliation(s)
- Hiteshika Gosain
- Institute of Integrative Cell Biology and Physiology, Department of Biology, University of Muenster, Münster, North-Rhine-Westphalia, Germany
| | - Karin B Busch
- Institute of Integrative Cell Biology and Physiology, Department of Biology, University of Muenster, Münster, North-Rhine-Westphalia, Germany.
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2
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Hou J, Mei K, Wang D, Ke S, Chen X, Shang J, Li G, Gao Y, Xiong H, Zhang H, Chen L, Zhang W, Deng Y, Hong X, Liu DA, Hu T, Guo W, Zhan YY. TGM1/3-mediated transamidation of Exo70 promotes tumor metastasis upon LKB1 inactivation. Cell Rep 2024; 43:114604. [PMID: 39146185 DOI: 10.1016/j.celrep.2024.114604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 05/10/2024] [Accepted: 07/24/2024] [Indexed: 08/17/2024] Open
Abstract
Exo70, a key exocyst complex component, is crucial for cell motility and extracellular matrix (ECM) remodeling in cancer metastasis. Despite its potential as a drug target, Exo70's post-translational modifications (PTMs) are poorly characterized. Here, we report that Exo70 is transamidated on Gln5 with Lys56 of cystatin A by transglutaminases TGM1 and TGM3, promoting tumor metastasis. This modification enhances Exo70's association with other exocyst subunits, essential for secreting matrix metalloproteinases, forming invadopodia, and delivering integrins to the leading edge. Tumor suppressor liver kinase B1 (LKB1), whose inactivation accelerates metastasis, phosphorylates TGM1 and TGM3 at Thr386 and Thr282, respectively, to inhibit their interaction with Exo70 and the following transamidation. Cantharidin, a US Food and Drug Administration (FDA)-approved drug, inhibits Exo70 transamidation to restrain tumor cell migration and invasion. Together, our findings highlight Exo70 transamidation as a key molecular mechanism and target and propose cantharidin as a therapeutic strategy with direct clinical translational value for metastatic cancers, especially those with LKB1 loss.
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Affiliation(s)
- Jihuan Hou
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Kunrong Mei
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China
| | - Daxuan Wang
- Department of Respiratory Medicine, Fujian Provincial Hospital, Fuzhou 350001, China
| | - Sunkui Ke
- Department of Thoracic Surgery, Zhongshan Hospital Affiliated to Xiamen University, Xiamen 361004, China
| | - Xiong Chen
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Jin Shang
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Guixia Li
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Yan Gao
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China
| | - Huifang Xiong
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China
| | - Haoran Zhang
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Lu Chen
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Wenqing Zhang
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Yabin Deng
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Xiaoting Hong
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Di-Ao Liu
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tianhui Hu
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China.
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Yan-Yan Zhan
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China.
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Li H, Fu X, Zhao J, Li C, Li L, Xia P, Guo J, Wei W, Zeng R, Wu J, Sun Y, Huang L, Wang X. EXOC4 Promotes Diffuse-Type Gastric Cancer Metastasis via Activating FAK Signal. Mol Cancer Res 2022; 20:1021-1034. [PMID: 35471457 PMCID: PMC9381130 DOI: 10.1158/1541-7786.mcr-21-0441] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/01/2021] [Accepted: 03/17/2022] [Indexed: 01/07/2023]
Abstract
In comparison with intestinal-type gastric cancer, diffuse-type gastric cancer (DGC) is more likely to recur, metastasize, and exhibit worse clinical outcomes; however, the underlying mechanism of DGC recurrence remains elusive. By employing an LC/MS-MS proteomic approach, we identified that exocyst complex component 4 (EXOC4) was significantly upregulated in DGC with recurrence, compared to those with nonrecurrence. High expression of EXOC4 was correlated with tumor metastasis and poor prognosis in patients with DGC. Moreover, EXOC4 promoted cell migration and invasion as well as the tumor metastasis of DGC cells. Mechanistically, EXOC4 regulated the phosphorylation of focal adhesion kinase (FAK) at Y397 sites by stimulating the secretion of integrin α5/β1/EGF and enhancing the interaction of FAK and integrin or EGFR. The FAK inhibitor VS-4718 reversed the metastasis mediated by EXOC4 overexpression and suppressed the tumor growth of patient-derived xenografts derived from DGC with high EXOC4 expression. The EXOC4-FAK axis could be a potential therapeutic target for patients with DGC with high expression of EXOC4. IMPLICATIONS The EXOC4-FAK axis promoted DGC metastasis and could be a potential therapeutic target for patients with DGC.
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Affiliation(s)
- Haojie Li
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China
| | - Xuhong Fu
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Junjie Zhao
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China
| | - Chen Li
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lingmeng Li
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Peiyan Xia
- University of Michigan-Shanghai Jiaotong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Jianping Guo
- Institute of Precision Medicine, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Rong Zeng
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jiarui Wu
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Yihong Sun
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Liyu Huang
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Xuefei Wang
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
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4
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Richardson DS, Spehar JM, Han DT, Chakravarthy PA, Sizemore ST. The RAL Enigma: Distinct Roles of RALA and RALB in Cancer. Cells 2022; 11:cells11101645. [PMID: 35626682 PMCID: PMC9139244 DOI: 10.3390/cells11101645] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/29/2022] [Accepted: 05/05/2022] [Indexed: 11/16/2022] Open
Abstract
RALA and RALB are highly homologous small G proteins belonging to the RAS superfamily. Like other small GTPases, the RALs are molecular switches that can be toggled between inactive GDP-bound and active GTP-bound states to regulate diverse and critical cellular functions such as vesicle trafficking, filopodia formation, mitochondrial fission, and cytokinesis. The RAL paralogs are activated and inactivated by a shared set of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) and utilize similar sets of downstream effectors. In addition to their important roles in normal cell biology, the RALs are known to be critical mediators of cancer cell survival, invasion, migration, and metastasis. However, despite their substantial similarities, the RALs often display striking functional disparities in cancer. RALA and RALB can have redundant, unique, or even antagonistic functions depending on cancer type. The molecular basis for these discrepancies remains an important unanswered question in the field of cancer biology. In this review we examine the functions of the RAL paralogs in normal cellular physiology and cancer biology with special consideration provided to situations where the roles of RALA and RALB are non-redundant.
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Hülsemann M, Sanchez C, Verkhusha PV, Des Marais V, Mao SPH, Donnelly SK, Segall JE, Hodgson L. TC10 regulates breast cancer invasion and metastasis by controlling membrane type-1 matrix metalloproteinase at invadopodia. Commun Biol 2021; 4:1091. [PMID: 34531530 PMCID: PMC8445963 DOI: 10.1038/s42003-021-02583-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 08/23/2021] [Indexed: 01/12/2023] Open
Abstract
During breast cancer metastasis, cancer cell invasion is driven by actin-rich protrusions called invadopodia, which mediate the extracellular matrix degradation required for the success of the invasive cascade. In this study, we demonstrate that TC10, a member of a Cdc42 subfamily of p21 small GTPases, regulates the membrane type 1 matrix metalloproteinase (MT1-MMP)-driven extracellular matrix degradation at invadopodia. We show that TC10 is required for the plasma membrane surface exposure of MT1-MMP at these structures. By utilizing our Förster resonance energy transfer (FRET) biosensor, we demonstrate the p190RhoGAP-dependent regulation of spatiotemporal TC10 activity at invadopodia. We identified a pathway that regulates invadopodia-associated TC10 activity and function through the activation of p190RhoGAP and the downstream interacting effector Exo70. Our findings reveal the role of a previously unknown regulator of vesicular fusion at invadopodia, TC10 GTPase, in breast cancer invasion and metastasis.
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Affiliation(s)
- Maren Hülsemann
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Colline Sanchez
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Polina V Verkhusha
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Vera Des Marais
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Analytical Imaging Facility, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Serena P H Mao
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Sara K Donnelly
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Jeffrey E Segall
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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6
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Zhao Y, Hong X, Chen X, Hu C, Lu W, Xie B, Zhong L, Zhang W, Cao H, Chen B, Liu Q, Zhan Y, Xiao L, Hu T. Deregulation of Exo70 Facilitates Innate and Acquired Cisplatin Resistance in Epithelial Ovarian Cancer by Promoting Cisplatin Efflux. Cancers (Basel) 2021; 13:cancers13143467. [PMID: 34298686 PMCID: PMC8304026 DOI: 10.3390/cancers13143467] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/04/2021] [Accepted: 07/08/2021] [Indexed: 11/25/2022] Open
Abstract
Simple Summary Innate and acquired platinum resistance are the leading causes of epithelial ovarian cancer (EOC) mortality. However, the mechanisms remain elusive. Here we found that Exo70, a key subunit of the exocyst, is upregulated in EOC and promotes cisplatin efflux to facilitate innate resistance. More interestingly, cisplatin could downregulate Exo70 to sustain cell sensitivity. However, this function was hampered during prolonged cisplatin treatment, which in turn stabilized Exo70 to facilitate the acquired cisplatin resistance of EOC cells. Our study potentiates Exo70 as a promising target to overcome cisplatin resistance in EOC. Abstract Whilst researches elucidating a diversity of intracellular mechanisms, platinum-resistant epithelial ovarian cancer (EOC) remains a major challenge in the treatment of ovarian cancer. Here we report that Exo70, a key subunit of the exocyst complex, contributes to both innate and acquired cisplatin resistance of EOC. Upregulation of Exo70 is observed in EOC tissues and is related to platinum resistance and progression-free survival of EOC patients. Exo70 suppressed the cisplatin sensitivity of EOC cells through promoting exocytosis-mediated efflux of cisplatin. Moreover, cisplatin-induced autophagy-lysosomal degradation of Exo70 protein by modulating phosphorylation of AMPK and mTOR, thereby reducing the cellular resistance. However, the function was hampered during prolonged cisplatin treatment, which in turn stabilized Exo70 to facilitate the acquired cisplatin resistance of EOC cells. Knockdown of Exo70, or inhibiting exocytosis by Exo70 inhibitor Endosidin2, reversed the cisplatin resistance of EOC cells both in vitro and in vivo. Our results suggest that Exo70 overexpression and excessive stability contribute to innate and acquired cisplatin resistance through the increase in cisplatin efflux, and targeting Exo70 might be an approach to overcome cisplatin resistance in EOC treatment.
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Affiliation(s)
- Yujie Zhao
- Department of Oncology, Zhongshan Hospital Affiliated to Xiamen University, Xiamen 361004, China;
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Xiaoting Hong
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Xiong Chen
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Chun Hu
- Department of Oncology, Xiamen Humanity Hospital, Fujian Medical University, Xiamen 361009, China;
| | - Weihong Lu
- Department of Obstetrics and Gynecology, Xiamen Branch, Zhongshan Hospital, Fudan University, Xiamen 361015, China;
| | - Baoying Xie
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Linhai Zhong
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Wenqing Zhang
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Hanwei Cao
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Binbin Chen
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Qian Liu
- Key Laboratory of the Education Ministry for the Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ganan Medical University, Ganzhou 341000, China;
| | - Yanyan Zhan
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
| | - Li Xiao
- Department of Oncology, Zhongshan Hospital Affiliated to Xiamen University, Xiamen 361004, China;
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
- Correspondence: (L.X.); (T.H.)
| | - Tianhui Hu
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen 361102, China; (X.H.); (X.C.); (B.X.); (L.Z.); (W.Z.); (H.C.); (B.C.); (Y.Z.)
- Key Laboratory of the Education Ministry for the Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ganan Medical University, Ganzhou 341000, China;
- Correspondence: (L.X.); (T.H.)
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7
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Loss of the exocyst complex component EXOC3 promotes hemostasis and accelerates arterial thrombosis. Blood Adv 2021; 5:674-686. [PMID: 33560379 DOI: 10.1182/bloodadvances.2020002515] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/28/2020] [Indexed: 11/20/2022] Open
Abstract
The exocyst is an octameric complex comprising 8 distinct protein subunits, exocyst complex components (EXOC) 1 to 8. It has an established role in tethering secretory vesicles to the plasma membrane, but its relevance to platelet granule secretion and function remains to be determined. Here, EXOC3 conditional knockout (KO) mice in the megakaryocyte/platelet lineage were generated to assess exocyst function in platelets. Significant defects in platelet aggregation, integrin activation, α-granule (P-selectin and platelet factor 4), dense granule, and lysosomal granule secretion were detected in EXOC3 KO platelets after treatment with a glycoprotein VI (GPVI)-selective agonist, collagen-related peptide (CRP). Except for P-selectin exposure, these defects were completely recovered by maximal CRP concentrations. GPVI surface levels were also significantly decreased by 14.5% in KO platelets, whereas defects in proximal GPVI signaling responses, Syk and LAT phosphorylation, and calcium mobilization were also detected, implying an indirect mechanism for these recoverable defects due to decreased surface GPVI. Paradoxically, dense granule secretion, integrin activation, and changes in surface expression of integrin αIIb (CD41) were significantly increased in KO platelets after protease-activated receptor 4 activation, but calcium responses were unaltered. Elevated integrin activation responses were completely suppressed with a P2Y12 receptor antagonist, suggesting enhanced dense granule secretion of adenosine 5'-diphosphate as a critical mediator of these responses. Finally, arterial thrombosis was significantly accelerated in KO mice, which also displayed improved hemostasis determined by reduced tail bleeding times. These findings reveal a regulatory role for the exocyst in controlling critical aspects of platelet function pertinent to thrombosis and hemostasis.
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8
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Daunys S, Petrikaitė V. The roles of carbonic anhydrases IX and XII in cancer cell adhesion, migration, invasion and metastasis. Biol Cell 2020; 112:383-397. [PMID: 32894882 DOI: 10.1111/boc.201900099] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 09/02/2012] [Indexed: 12/17/2022]
Abstract
The main function of carbonic anhydrases (CAs) in cancer cells is the pH regulation through a conversion of H2 O and CO2 to H+ and HCO3 - . However, the data of in vitro and in vivo studies have demonstrated that transmembrane isoforms of CA IX and CA XII are involved in various steps of cancer cell migration, invasion and metastasis. According to literature, inhibition of these CAs can affect the expression of multiple proteins. Some scientific groups have reported the possible interactions between CA IX and E-cadherin-catenin system, CA IX and integrins, CA IX, CA XII and ion transporters, which all are highly involved in cell-to-cell adhesion, the formation of membrane protrusions and focal adhesions. Nevertheless, CA IX and CA XII have a high impact on tumour growth and metastases formation. The data discussed in this review are quite recent. It highly support the role of CA IX and CA XII in various cancer metastasis processes through their interactions to other invasion proteins. Nevertheless, all findings show the great potential of these CAs in the context of research and application in clinical use.
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Affiliation(s)
- Simonas Daunys
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, LT-10257, Lithuania
| | - Vilma Petrikaitė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, LT-10257, Lithuania.,Laboratory of Drug Targets Histopathology, Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, LT-50162, Lithuania
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9
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Rohena C, Rajapakse N, Lo IC, Novick P, Sahoo D, Ghosh P. GIV/Girdin and Exo70 Collaboratively Regulate the Mammalian Polarized Exocytic Machinery. iScience 2020; 23:101246. [PMID: 32590327 PMCID: PMC7322189 DOI: 10.1016/j.isci.2020.101246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 04/20/2020] [Accepted: 06/03/2020] [Indexed: 11/17/2022] Open
Abstract
Polarized exocytosis is a fundamental process by which membranes and cargo proteins are delivered to the cell surface with precise spatial control. Although the need for the octameric exocyst complex is conserved from yeast to humans, what imparts spatial control is known only in yeast, i.e., a polarity scaffold called Bem1p. We demonstrate here that the mammalian scaffold protein, GIV/Girdin, fulfills the key criteria and functions of its yeast counterpart Bem1p; both bind Exo70 proteins via similar short-linear interaction motifs, and each prefers its evolutionary counterpart. Selective disruption of the GIV⋅Exo-70 interaction derails the delivery of the metalloprotease MT1-MMP to invadosomes and impairs collagen degradation and haptotaxis through basement membrane matrix. GIV's interacting partners reveal other components of polarized exocytosis in mammals. Findings expose how the exocytic functions aid GIV's pro-metastatic functions and how signal integration via GIV may represent an evolutionary advancement of the exocytic process in mammals.
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Affiliation(s)
- Cristina Rohena
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 232, 239, La Jolla, CA 92093, USA
| | - Navin Rajapakse
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - I-Chung Lo
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Debashis Sahoo
- Department of Pediatrics, University of California San Diego, San Diego, CA 92093, USA; Department of Computer Science and Engineering, Jacob's School of Engineering, University of California San Diego, San Diego, CA 92093, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, San Diego, CA 92093, USA
| | - Pradipta Ghosh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 232, 239, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, San Diego, CA 92093, USA; Veterans Affairs Medical Center, 3350 La Jolla Village Dr, San Diego, CA 92161, USA.
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10
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ULK1 phosphorylates Exo70 to suppress breast cancer metastasis. Nat Commun 2020; 11:117. [PMID: 31913283 PMCID: PMC6949295 DOI: 10.1038/s41467-019-13923-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 12/02/2019] [Indexed: 01/17/2023] Open
Abstract
Increased expression of protein kinase ULK1 was reported to negatively correlate with breast cancer metastasis. Here we report that ULK1 suppresses the migration and invasion of human breast cancer cells. The suppressive effect is mediated through direct phosphorylation of Exo70, a key component of the exocyst complex. ULK1 phosphorylation inhibits Exo70 homo-oligomerization as well as its assembly to the exocyst complex, which are needed for cell protrusion formation and matrix metalloproteinases secretion during cell invasion. Reversely, upon growth factor stimulation, Exo70 is phosphorylated by ERK1/2, which in turn suppresses its phosphorylation by ULK1. Together, our study identifies Exo70 as a substrate of ULK1 that inhibits cancer metastasis, and demonstrates that two counteractive regulatory mechanisms are well orchestrated during tumor cell invasion. Elevated expression of ULK1 is known to be inversely correlated with breast cancer metastasis. Here, the authors report Exo70 as a substrate of ULK1 that suppresses cancer metastasis, and show that ERK1/2 mediated phosphorylation of Exo70 leads to opposing effects on tumour cell invasion.
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11
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Moreiras H, Pereira FJC, Neto MV, Bento-Lopes L, Festas TC, Seabra MC, Barral DC. The exocyst is required for melanin exocytosis from melanocytes and transfer to keratinocytes. Pigment Cell Melanoma Res 2019; 33:366-371. [PMID: 31665827 DOI: 10.1111/pcmr.12840] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/07/2019] [Accepted: 10/22/2019] [Indexed: 11/30/2022]
Abstract
Skin pigmentation involves the production of the pigment melanin by melanocytes, in melanosomes and subsequent transfer to keratinocytes. Within keratinocytes, melanin polarizes to the apical perinuclear region to form a protective cap, shielding the DNA from ultraviolet radiation-induced damage. Previously, we found evidence to support the exocytosis by melanocytes of the melanin core, termed melanocore, followed by endo/phagocytosis by keratinocytes as a main form of transfer, with Rab11b playing a key role in the process. Here, we report the requirement for the exocyst tethering complex in melanocore exocytosis and transfer to keratinocytes. We observed that the silencing of the exocyst subunits Sec8 or Exo70 impairs melanocore exocytosis from melanocytes, without affecting melanin synthesis. Moreover, we confirmed by immunoprecipitation that Rab11b interacts with Sec8 in melanocytes. Furthermore, we found that the silencing of Sec8 or Exo70 in melanocytes impairs melanin transfer to keratinocytes. These results support our model as melanocore exocytosis from melanocytes is essential for melanin transfer to keratinocytes and skin pigmentation and suggest that the role of Rab11b in melanocore exocytosis is mediated by the exocyst.
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Affiliation(s)
- Hugo Moreiras
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Francisco J C Pereira
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Matilde V Neto
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Liliana Bento-Lopes
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Tiago C Festas
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Miguel C Seabra
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Duarte C Barral
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
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12
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Qian X, Zhou X, Shentu P, Yao Y, Jiao D, Chen Q, Zhou J, Xu Y. Sec3 knockdown inhibits TGF-β induced epithelial-mesenchymal transition through the down-regulation of Akt phosphorylation in A549 cells. Biochem Biophys Res Commun 2019; 519:253-260. [PMID: 31495494 DOI: 10.1016/j.bbrc.2019.08.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 08/26/2019] [Indexed: 11/17/2022]
Abstract
The exocyst, an evolutionarily conserved octomeric protein complex, has been demonstrated as an essential component for vesicle tethering during cell exocytosis, and participates in various physiological processes in the cell. Although subunits of the exocyst complex have been reported to be involved in the regulation of TGF-β induced cancer cell migration and epithelial-mesenchymal transition (EMT), the potential function of Sec3 in these regulated processes remains unclear. Here, we show that Sec3 knockdown abolishes TGF-β stimulated A549 lung cancer cell migration in vitro and causes defects in the regulated EMT process. In addition, we find that depletion of Sec3 significantly inhibits TGF-β stimulated Akt phosphorylation in A549 cells, whereas the increase of Smad2 phosphorylation is unaffected. Furthermore, replenishment of an RNAi-resistant form of Sec3 is shown to restore the defects of TGF-β induced cell migration, EMT and Akt signaling activation. In summary, our study provides evidence that Sec3 is involved in TGF-β induced cell migration and EMT processes, presumably through the regulation of PI3K/Akt signaling activation in A549 cancer cells.
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Affiliation(s)
- Xiaohan Qian
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China; Department of Respiratory Disease, Thoracic Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Xiaoxu Zhou
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China
| | - Ping Shentu
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China
| | - Yuanfa Yao
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China
| | - Demin Jiao
- Department of Respiratory Oncology, The 903rd Hospital of PLA, Hangzhou, 310013, China
| | - Qingyong Chen
- Department of Respiratory Oncology, The 903rd Hospital of PLA, Hangzhou, 310013, China
| | - Jianying Zhou
- Department of Respiratory Disease, Thoracic Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Yingke Xu
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China; Department of Endocrinology, The Affiliated Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
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13
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Sáez JJ, Diaz J, Ibañez J, Bozo JP, Cabrera Reyes F, Alamo M, Gobert FX, Obino D, Bono MR, Lennon-Duménil AM, Yeaman C, Yuseff MI. The exocyst controls lysosome secretion and antigen extraction at the immune synapse of B cells. J Cell Biol 2019; 218:2247-2264. [PMID: 31197029 PMCID: PMC6605794 DOI: 10.1083/jcb.201811131] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 04/11/2019] [Accepted: 05/22/2019] [Indexed: 02/06/2023] Open
Abstract
BCR engagement enhances microtubule stability, which triggers the mobilization of Exo70 from the centrosome to the immune synapse. BCR engagement activates GEF-H1, which promotes exocyst assembly required for the docking and secretion of lysosomes, facilitating the extraction of surface-tethered antigens. B lymphocytes capture antigens from the surface of presenting cells by forming an immune synapse. Local secretion of lysosomes, which are guided to the synaptic membrane by centrosome repositioning, can facilitate the extraction of immobilized antigens. However, the molecular basis underlying their delivery to precise domains of the plasma membrane remains elusive. Here we show that microtubule stabilization, triggered by engagement of the B cell receptor, acts as a cue to release centrosome-associated Exo70, which is redistributed to the immune synapse. This process is coupled to the recruitment and activation of GEF-H1, which is required for assembly of the exocyst complex, used to promote tethering and fusion of lysosomes at the immune synapse. B cells silenced for GEF-H1 or Exo70 display defective lysosome secretion, which results in impaired antigen extraction and presentation. Thus, centrosome repositioning coupled to changes in microtubule stability orchestrates the spatial-temporal distribution of the exocyst complex to promote polarized lysosome secretion at the immune synapse.
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Affiliation(s)
- Juan José Sáez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Jheimmy Diaz
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge Ibañez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Pablo Bozo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernanda Cabrera Reyes
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Martina Alamo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - François-Xavier Gobert
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - Dorian Obino
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - María Rosa Bono
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Ana-María Lennon-Duménil
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - Charles Yeaman
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA
| | - María-Isabel Yuseff
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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14
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Zhang X, Xing XX, Cui JF. Invadopodia formation: An important step in matrix stiffness-regulated tumor invasion and metastasis. Shijie Huaren Xiaohua Zazhi 2019; 27:589-597. [DOI: 10.11569/wcjd.v27.i9.589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Highly motile and invasive abilities are symbolic features of metastatic tumor cells. Being a critical molecular event for maintaining the highly migratory and invasive capabilities of tumor cells, invadopodia formation undoubtedly determines the progression of tumor invasion and metastasis. Growing numbers of studies suggest that increased matrix stiffness, as a notable property of physical mechanics in solid tumors, participates in the regulation of tumor invasion and metastasis via different molecular mechanisms. However, to date the relevant mechanisms of matrix stiffness-induced invadopodia formation and activity in tumor cells remain largely unclear. This paper is to make a review on the structure and function of invadopodia, the stages and inductive factors of invadopodia formation, the regulatory mechanisms of matrix stiffness-induced invadopodia formation and so on, with an aim to reveal the important roles of invadopodia in matrix stiffness-regulated tumor invasion and metastasis.
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Affiliation(s)
- Xi Zhang
- Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xiao-Xia Xing
- Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jie-Feng Cui
- Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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15
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Peláez R, Pariente A, Pérez-Sala Á, Larrayoz IM. Integrins: Moonlighting Proteins in Invadosome Formation. Cancers (Basel) 2019; 11:cancers11050615. [PMID: 31052560 PMCID: PMC6562994 DOI: 10.3390/cancers11050615] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 12/24/2022] Open
Abstract
Invadopodia are actin-rich protrusions developed by transformed cells in 2D/3D environments that are implicated in extracellular matrix (ECM) remodeling and degradation. These structures have an undoubted association with cancer invasion and metastasis because invadopodium formation in vivo is a key step for intra/extravasation of tumor cells. Invadopodia are closely related to other actin-rich structures known as podosomes, which are typical structures of normal cells necessary for different physiological processes during development and organogenesis. Invadopodia and podosomes are included in the general term 'invadosomes,' as they both appear as actin puncta on plasma membranes next to extracellular matrix metalloproteinases, although organization, regulation, and function are slightly different. Integrins are transmembrane proteins implicated in cell-cell and cell-matrix interactions and other important processes such as molecular signaling, mechano-transduction, and cell functions, e.g., adhesion, migration, or invasion. It is noteworthy that integrin expression is altered in many tumors, and other pathologies such as cardiovascular or immune dysfunctions. Over the last few years, growing evidence has suggested a role of integrins in the formation of invadopodia. However, their implication in invadopodia formation and adhesion to the ECM is still not well known. This review focuses on the role of integrins in invadopodium formation and provides a general overview of the involvement of these proteins in the mechanisms of metastasis, taking into account classic research through to the latest and most advanced work in the field.
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Affiliation(s)
- Rafael Peláez
- Biomarkers and Molecular Signaling Group, Neurodegenerative Diseases Area Center for Biomedical Research of La Rioja, CIBIR, c.p., 26006. Logroño, Spain.
| | - Ana Pariente
- Biomarkers and Molecular Signaling Group, Neurodegenerative Diseases Area Center for Biomedical Research of La Rioja, CIBIR, c.p., 26006. Logroño, Spain.
| | - Álvaro Pérez-Sala
- Biomarkers and Molecular Signaling Group, Neurodegenerative Diseases Area Center for Biomedical Research of La Rioja, CIBIR, c.p., 26006. Logroño, Spain.
| | - Ignacio M Larrayoz
- Biomarkers and Molecular Signaling Group, Neurodegenerative Diseases Area Center for Biomedical Research of La Rioja, CIBIR, c.p., 26006. Logroño, Spain.
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16
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Identification and Characterization of the EXO70 Gene Family in Polyploid Wheat and Related Species. Int J Mol Sci 2018; 20:ijms20010060. [PMID: 30586859 PMCID: PMC6337732 DOI: 10.3390/ijms20010060] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/13/2018] [Accepted: 12/21/2018] [Indexed: 12/24/2022] Open
Abstract
The EXO70 gene family is involved in different biological processes in plants, ranging from plant polar growth to plant immunity. To date, analysis of the EXO70 gene family has been limited in Triticeae species, e.g., hexaploidy Triticum aestivum and its ancestral/related species. By in silico analysis of multiple Triticeae sequence databases, a total of 200 EXO70 members were identified. By homologue cloning approaches, 15 full-length cDNA of EXO70s were cloned from diploid Haynaldia villosa. Phylogenetic relationship analysis of 215 EXO70 members classified them into three groups (EXO70.1, EXO70.2, and EXO70.3) and nine subgroups (EXO70A to EXO70I). The distribution of most EXO70 genes among different species/sub-genomes were collinear, implying their orthologous relationship. The EXO70A subgroup has the most introns (at least five introns), while the remaining seven subgroups have only one intron on average. The expression profiling of EXO70 genes from wheat revealed that 40 wheat EXO70 genes were expressed in at least one tissue (leaf, stem, or root), of which 25 wheat EXO70 genes were in response to at least one biotic stress (stripe rust or powdery mildew) or abiotic stress (drought or heat). Subcellular localization analysis showed that ten EXO70-V proteins had distinct plasma membrane localization, EXO70I1-V showed a distinctive spotted pattern on the membrane. The 15 EXO70-V genes were differentially expressed in three tissue. Apart from EXO70D2-V, the remaining EXO70-V genes were in response to at least one stress (flg22, chitin, powdery mildew, drought, NaCl, heat, or cold) or phytohormones (salicylic acid, methyl jasmonate, ethephon, or abscisic acid) and hydrogen peroxide treatments. This research provides a genome-wide glimpse of the Triticeae EXO70 gene family and those up- or downregulated genes require further validation of their biological roles in response to biotic/abiotic stresses.
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17
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Lira M, Arancibia D, Orrego PR, Montenegro-Venegas C, Cruz Y, García J, Leal-Ortiz S, Godoy JA, Gundelfinger ED, Inestrosa NC, Garner CC, Zamorano P, Torres VI. The Exocyst Component Exo70 Modulates Dendrite Arbor Formation, Synapse Density, and Spine Maturation in Primary Hippocampal Neurons. Mol Neurobiol 2018; 56:4620-4638. [DOI: 10.1007/s12035-018-1378-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 10/01/2018] [Indexed: 02/07/2023]
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18
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Polgar N, Fogelgren B. Regulation of Cell Polarity by Exocyst-Mediated Trafficking. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a031401. [PMID: 28264817 DOI: 10.1101/cshperspect.a031401] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
One requirement for establishing polarity within a cell is the asymmetric trafficking of intracellular vesicles to the plasma membrane. This tightly regulated process creates spatial and temporal differences in both plasma membrane composition and the membrane-associated proteome. Asymmetric membrane trafficking is also a critical mechanism to regulate cell differentiation, signaling, and physiology. Many eukaryotic cell types use the eight-protein exocyst complex to orchestrate polarized vesicle trafficking to certain membrane locales. Members of the exocyst were originally discovered in yeast while screening for proteins required for the delivery of secretory vesicles to the budding daughter cell. The same eight exocyst genes are conserved in mammals, in which the specifics of exocyst-mediated trafficking are highly cell-type-dependent. Some exocyst members bind to certain Rab GTPases on intracellular vesicles, whereas others localize to the plasma membrane at the site of exocytosis. Assembly of the exocyst holocomplex is responsible for tethering these vesicles to the plasma membrane before their soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated exocytosis. In this review, we will focus on the role and regulation of the exocyst complex in targeted vesicular trafficking as related to the establishment and maintenance of cellular polarity. We will contrast exocyst function in apicobasal epithelial polarity versus front-back mesenchymal polarity, and the dynamic regulation of exocyst-mediated trafficking during cell phenotype transitions.
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Affiliation(s)
- Noemi Polgar
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813
| | - Ben Fogelgren
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813
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19
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Liang D. A Salutary Role of Reactive Oxygen Species in Intercellular Tunnel-Mediated Communication. Front Cell Dev Biol 2018; 6:2. [PMID: 29503816 PMCID: PMC5821100 DOI: 10.3389/fcell.2018.00002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/18/2018] [Indexed: 12/17/2022] Open
Abstract
The reactive oxygen species, generally labeled toxic due to high reactivity without target specificity, are gradually uncovered as signaling molecules involved in a myriad of biological processes. But one important feature of ROS roles in macromolecule movement has not caught attention until recent studies with technique advance and design elegance have shed lights on ROS signaling for intercellular and interorganelle communication. This review begins with the discussions of genetic and chemical studies on the regulation of symplastic dye movement through intercellular tunnels in plants (plasmodesmata), and focuses on the ROS regulatory mechanisms concerning macromolecule movement including small RNA-mediated gene silencing movement and protein shuttling between cells. Given the premise that intercellular tunnels (bridges) in mammalian cells are the key physical structures to sustain intercellular communication, movement of macromolecules and signals is efficiently facilitated by ROS-induced membrane protrusions formation, which is analogously applied to the interorganelle communication in plant cells. Although ROS regulatory differences between plant and mammalian cells exist, the basis for ROS-triggered conduit formation underlies a unifying conservative theme in multicellular organisms. These mechanisms may represent the evolutionary advances that have enabled multicellularity to gain the ability to generate and utilize ROS to govern material exchanges between individual cells in oxygenated environment.
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Affiliation(s)
- Dacheng Liang
- Hubei Collaborative Innovation Center for Grain Industry, School of Agriculture, Yangtze University, Jingzhou, China.,Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, Yangtze University, Jingzhou, China
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20
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Abstract
Polarized exocytosis is generally considered as the multistep vesicular trafficking process in which membrane-bounded carriers are transported from the Golgi or endosomal compartments to specific sites of the plasma membrane. Polarized exocytosis in cells is achieved through the coordinated actions of membrane trafficking machinery and cytoskeleton orchestrated by signaling molecules such as the Rho family of small GTPases. Elucidating the molecular mechanisms of polarized exocytosis is essential to our understanding of a wide range of pathophysiological processes from neuronal development to tumor invasion.
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Affiliation(s)
- Jingwen Zeng
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Shanshan Feng
- Key Laboratory for Regenerative Medicine of Ministry of Education and Department of Developmental & Regenerative Biology, Jinan University, Guangzhou 510632, P.R. China
| | - Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
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21
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Xiao L, Zheng K, Lv X, Hou J, Xu L, Zhao Y, Song F, Fan Y, Cao H, Zhang W, Hong X, Zhan YY, Hu T. Exo70 is an independent prognostic factor in colon cancer. Sci Rep 2017; 7:5039. [PMID: 28698570 PMCID: PMC5505949 DOI: 10.1038/s41598-017-05308-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/26/2017] [Indexed: 12/31/2022] Open
Abstract
Exo70, a key component of the Exocyst complex, plays important roles in human cancer progression beyond exocytosis. However, the expression of Exo70 and its prognostic value for patients with colon cancer has not been well investigated to date. In this study, we observed that the mRNA and protein levels of Exo70 were upregulated in 11 of 13 colon cancer tissues, compared with their normal counterparts, which was validated by immunohistochemical analysis in a tissue microarray containing 89 pairs of colon cancer tissues and the matched adjacent normal tissues. Statistical analysis revealed that Exo70 expression is positively correlated with tumor size, invasion depth, TNM stage and distant metastasis. Kaplan-Meier survival analysis showed that colon cancer patients with higher Exo70 expression have a poorer clinical outcome than those with lower Exo70 expression. Multivariate Cox regression analysis revealed that Exo70, age and distant metastasis were there independent prognostic factors for overall survival rate of colon cancer patients. Through gain- and loss of Exo70 in colon cancer cells, we found that Exo70 could enhance the migration ability of colon cancer cells. Taken together, our studies revealed that Exo70 might be a promising negative prognostic factor and a potential therapeutic target for colon cancer.
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Affiliation(s)
- Li Xiao
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
- Department of Oncology, Zhongshan Hospital Affiliated to Xiamen University, Xiamen, 361004, Fujian Province, P.R. China
| | - Kaifeng Zheng
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Xia Lv
- Department of Oncology, Zhongshan Hospital Affiliated to Xiamen University, Xiamen, 361004, Fujian Province, P.R. China
| | - Jihuan Hou
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Liang Xu
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Yujie Zhao
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Fei Song
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Yaqiong Fan
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Hanwei Cao
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Wenqing Zhang
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Xiaoting Hong
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China
| | - Yan-Yan Zhan
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China.
| | - Tianhui Hu
- Cancer Research Center, Xiamen University Medical College, Xiamen, 361102, Fujian Province, P.R. China.
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22
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Paterson EK, Courtneidge SA. Invadosomes are coming: new insights into function and disease relevance. FEBS J 2017; 285:8-27. [PMID: 28548369 DOI: 10.1111/febs.14123] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/09/2017] [Accepted: 05/24/2017] [Indexed: 12/21/2022]
Abstract
Invadopodia and podosomes are discrete, actin-based molecular protrusions that form in cancer cells and normal cells, respectively, in response to diverse signaling pathways and extracellular matrix cues. Although they participate in a host of different cellular processes, they share a common functional theme of controlling pericellular proteolytic activity, which sets them apart from other structures that function in migration and adhesion, including focal adhesions, lamellipodia, and filopodia. In this review, we highlight research that explores the function of these complex structures, including roles for podosomes in embryonic and postnatal development, in angiogenesis and remodeling of the vasculature, in maturation of the postsynaptic membrane, in antigen sampling and recognition, and in cell-cell fusion mechanisms, as well as the involvement of invadopodia at multiple steps of the metastatic cascade, and how all of this may apply in the treatment of human disease states. Finally, we explore recent research that implicates a novel role for exosomes and microvesicles in invadopodia-dependent and invadopodia-independent mechanisms of invasion, respectively.
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Affiliation(s)
- Elyse K Paterson
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR, USA
| | - Sara A Courtneidge
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR, USA.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, USA.,Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
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23
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Abstract
The exocyst complex mediates the tethering of secretory vesicles to the plasma membrane before SNARE-mediated membrane fusion. Recent studies have implicated the exocyst in a wide range of cellular processes. Particularly, research on the Exo70 subunit of the complex has linked the function of the exocyst in exocytosis to cell adhesion, migration and invasion. In this review, we will discuss the recent work on how Exo70 regulates these cellular processes, and how small GTPases and kinases interact with Exo70 to orchestrate its function in exocytosis and cytoskeleton organization. The study of Exo70 contributes to the understanding of many pathophysiological processes from organogenesis to cancer metastasis.
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Affiliation(s)
- Yueyao Zhu
- a Department of Biology, University of Pennsylvania , Philadelphia , PA , USA
| | - Bin Wu
- a Department of Biology, University of Pennsylvania , Philadelphia , PA , USA
| | - Wei Guo
- a Department of Biology, University of Pennsylvania , Philadelphia , PA , USA
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24
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Zago G, Biondini M, Camonis J, Parrini MC. A family affair: A Ral-exocyst-centered network links Ras, Rac, Rho signaling to control cell migration. Small GTPases 2017; 10:323-330. [PMID: 28498728 DOI: 10.1080/21541248.2017.1310649] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Cell migration is central to many developmental, physiologic and pathological processes, including cancer progression. The Ral GTPases (RalA and RalB) which act down-stream the Ras oncogenes, are key players in the coordination between membrane trafficking and actin polymerization. A major direct effector of Ral, the exocyst complex, works in polarized exocytosis and is at the center of multiple protein-protein interactions that support cell migration by promoting protrusion formation, front-rear polarization, and extra-cellular matrix degradation. In this review we describe the recent advancements in deciphering the molecular mechanisms underlying this role of Ral via exocyst on cell migration. Among others, we will discuss the recently identified cross-talk between Ral and Rac1 pathways: exocyst binds to a negative regulator (the RacGAP SH3BP1) and to the major effector (the Wave Regulatory Complex, WRC) of Rac1, the master regulator of protrusions. Next challenge will be to better characterize the dynamics in space and in time of these molecular interplays, to better understand the pleiotropic functions of Ral in both normal and cancer cells.
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Affiliation(s)
- Giulia Zago
- a Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University , Paris , France.,b ART group, Inserm U830 , Paris , France
| | - Marco Biondini
- a Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University , Paris , France.,b ART group, Inserm U830 , Paris , France
| | - Jacques Camonis
- a Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University , Paris , France.,b ART group, Inserm U830 , Paris , France
| | - Maria Carla Parrini
- a Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University , Paris , France.,b ART group, Inserm U830 , Paris , France
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25
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Abstract
Exocytosis is a fundamental cellular process whereby secreted molecules are packaged into vesicles that move along cytoskeletal filaments and fuse with the plasma membrane. To function optimally, cells are strongly dependent on precisely controlled delivery of exocytotic cargo. In mammalian cells, microtubules serve as major tracks for vesicle transport by motor proteins, and thus microtubule organization is important for targeted delivery of secretory carriers. Over the years, multiple microtubule-associated and cortical proteins have been discovered that facilitate the interaction between the microtubule plus ends and the cell cortex. In this review, we focus on mammalian protein complexes that have been shown to participate in both cortical microtubule capture and exocytosis, thereby regulating the spatial organization of secretion. These complexes include microtubule plus-end tracking proteins, scaffolding factors, actin-binding proteins, and components of vesicle docking machinery, which together allow efficient coordination of cargo transport and release.
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Affiliation(s)
- Ivar Noordstra
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands
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26
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Tanaka T, Goto K, Iino M. Diverse Functions and Signal Transduction of the Exocyst Complex in Tumor Cells. J Cell Physiol 2016; 232:939-957. [DOI: 10.1002/jcp.25619] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 09/23/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Toshiaki Tanaka
- Department of Anatomy and Cell Biology; School of Medicine; Yamagata University; Yamagata Japan
- Department of Dentistry, Oral and Maxillofacial Surgery; Plastic and Reconstructive Surgery; School of Medicine; Yamagata University; Yamagata Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology; School of Medicine; Yamagata University; Yamagata Japan
| | - Mitsuyoshi Iino
- Department of Dentistry, Oral and Maxillofacial Surgery; Plastic and Reconstructive Surgery; School of Medicine; Yamagata University; Yamagata Japan
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27
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Ma W, Wang Y, Yao X, Xu Z, An L, Yin M. The role of Exo70 in vascular smooth muscle cell migration. Cell Mol Biol Lett 2016; 21:20. [PMID: 28536622 PMCID: PMC5415710 DOI: 10.1186/s11658-016-0019-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 09/10/2016] [Indexed: 01/05/2023] Open
Abstract
Background As a key subunit of the exocyst complex, Exo70 has highly conserved sequence and is widely found in yeast, mammals, and plants. In yeast, Exo70 mediates the process of exocytosis and promotes anchoring and integration of vesicles with the plasma membrane. In mammalian cells, Exo70 is involved in maintaining cell morphology, cell migration, cell connection, mRNA splicing, and other physiological processes, as well as participating in exocytosis. However, Exo70’s function in mammalian cells has yet to be fully recognized. In this paper, the expression of Exo70 and its role in cell migration were studied in a rat vascular smooth muscle cell line A7r5. Methods Immunofluorescent analysis the expression of Exo70, α-actin, and tubulin in A7r5 cells showed a co-localization of Exo70 and α-actin, we treated the cells with cytochalasin B to depolymerize α-actin, in order to further confirm the co-localization of Exo70 and α-actin. We analyzed Exo70 co-localization with actin at the edge of migrating cells by wound-healing assay to establish whether Exo70 might play a role in cell migration. Next, we analyzed the migration and invasion ability of A7r5 cells before and after RNAi silencing through the wound healing assay and transwell assay. Results The mechanism of interaction between Exo70 and cytoskeleton can be clarified by the immunoprecipitation techniques and wound-healing assay. The results showed that Exo70 and α-actin were co-localized at the leading edge of migrating cells. The ability of A7r5 to undergo cell migration was decreased when Exo70 expression was silenced by RNAi. Reducing Exo70 expression in RNAi treated A7r5 cells significantly lowered the invasion and migration ability of these cells compared to the normal cells. These results indicate that Exo70 participates in the process of A7r5 cell migration. Conclusions This research is importance for the study on the pathological process of vascular intimal hyperplasia, since it provides a new research direction for the treatment of cardiovascular diseases such as atherosclerosis and restenosis after balloon angioplasty.
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Affiliation(s)
- Wenqing Ma
- Key Laboratory of Animal Resistant Biology of Shandong, College of Life Science, Shandong Normal University, Jinan, 250014 People's Republic of China
| | - Yu Wang
- Shandong Provincial Hospital affiliated to Shandong University, Jinan, 250014 People's Republic of China
| | - Xiaomeng Yao
- Key Laboratory of Animal Resistant Biology of Shandong, College of Life Science, Shandong Normal University, Jinan, 250014 People's Republic of China.,No.10 High School of Zibo, Zibo, 255000 People's Republic of China
| | - Zijian Xu
- Key Laboratory of Animal Resistant Biology of Shandong, College of Life Science, Shandong Normal University, Jinan, 250014 People's Republic of China
| | - Liguo An
- Key Laboratory of Animal Resistant Biology of Shandong, College of Life Science, Shandong Normal University, Jinan, 250014 People's Republic of China
| | - Miao Yin
- Key Laboratory of Animal Resistant Biology of Shandong, College of Life Science, Shandong Normal University, Jinan, 250014 People's Republic of China
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28
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Castro-Castro A, Marchesin V, Monteiro P, Lodillinsky C, Rossé C, Chavrier P. Cellular and Molecular Mechanisms of MT1-MMP-Dependent Cancer Cell Invasion. Annu Rev Cell Dev Biol 2016; 32:555-576. [PMID: 27501444 DOI: 10.1146/annurev-cellbio-111315-125227] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metastasis is responsible for most cancer-associated deaths. Accumulating evidence based on 3D migration models has revealed a diversity of invasive migratory schemes reflecting the plasticity of tumor cells to switch between proteolytic and nonproteolytic modes of invasion. Yet, initial stages of localized regional tumor dissemination require proteolytic remodeling of the extracellular matrix to overcome tissue barriers. Recent data indicate that surface-exposed membrane type 1-matrix metalloproteinase (MT1-MMP), belonging to a group of membrane-anchored MMPs, plays a central role in pericellular matrix degradation during basement membrane and interstitial tissue transmigration programs. In addition, a large body of work indicates that MT1-MMP is targeted to specialized actin-rich cell protrusions termed invadopodia, which are responsible for matrix degradation. This review describes the multistep assembly of actin-based invadopodia in molecular details. Mechanisms underlying MT1-MMP traffic to invadopodia through endocytosis/recycling cycles, which are key to the invasive program of carcinoma cells, are discussed.
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Affiliation(s)
| | | | - Pedro Monteiro
- Barts Cancer Institute, University of London John Vane Science Centre, London EC1M 6BQ, United Kingdom
| | - Catalina Lodillinsky
- Instituto de Oncologia Ángel H. Roffo, Research Area, Buenos Aires, C1417DTB, Argentina
| | - Carine Rossé
- Institut Curie, Paris, F-75248 France; .,PSL Research University, Paris, F-75005 France.,CNRS, UMR 144, Paris, F-75248 France
| | - Philippe Chavrier
- Institut Curie, Paris, F-75248 France; .,PSL Research University, Paris, F-75005 France.,CNRS, UMR 144, Paris, F-75248 France
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29
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Inamdar SM, Hsu SC, Yeaman C. Probing Functional Changes in Exocyst Configuration with Monoclonal Antibodies. Front Cell Dev Biol 2016; 4:51. [PMID: 27376061 PMCID: PMC4891948 DOI: 10.3389/fcell.2016.00051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/10/2016] [Indexed: 01/19/2023] Open
Abstract
Spatial regulation of exocytosis relies on the exocyst, a hetero-octameric protein complex that tethers vesicles to fusion sites at the plasma membrane. Nevertheless, our understanding of mechanisms regulating exocyst assembly/disassembly, localization, and function are incomplete. Here, we have exploited a panel of anti-Sec6 monoclonal antibodies (mAbs) to probe possible configurational changes accompanying transitions in exocyst function in epithelial MDCK cells. Sec6 is quantitatively associated with Sec8 in high molecular weight complexes, as shown by gel filtration and co-immunoprecipitation studies. We mapped epitopes recognized by more than 20 distinct mAbs to one of six Sec6 segments. Surprisingly, mAbs that bound epitopes in each segment labeled distinct subcellular structures. In general, antibodies to epitopes in N-terminal domains labeled Sec6 in either cytosolic or nuclear pools, whereas those that bound epitopes in C-terminal domains labeled membrane-associated Sec6. In this latter group, we identified antibodies that labeled distinct Sec6 populations at the apical junctional complex, desmosomes, endoplasmic reticulum and vimentin-type intermediate filaments. That each antibody was specific was verified by both Sec6 RNAi and competition with fusion proteins containing each domain. Comparison of non-polarized and polarized cells revealed that many Sec6 epitopes either redistribute or become concealed during epithelial polarization. Transitions in exocyst configurations may be regulated in part by the actions of Ral GTPases, because the exposure of Sec6 C-terminal domain epitopes at the plasma membrane is significantly reduced upon RalA RNAi. To determine whether spatio-temporal changes in epitope accessibility was correlated with differential stability of interactions between Sec6 and other exocyst subunits, we quantified relative amounts of each subunit that co-immunoprecipitated with Sec6 when antibodies to N-terminal or C-terminal epitopes were used. Antibodies to Sec6NT co-precipitated substantially more Sec5, -10, -15, Exo70 and -84 than did those to Sec6CT. In contrast, antibodies to Sec6CT co-precipitated more Sec3 and Sec8 than did those to Sec6NT. These results are consistent with a model in which exocyst activation during periods of rapid membrane expansion is accompanied by molecular rearrangements within the holocomplex or association with accessory proteins, which expose the Sec6 C-terminal domain when the complex is membrane-bound and conceal it when the complex is cytoplasmic.
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Affiliation(s)
- Shivangi M Inamdar
- Molecular and Cellular Biology Program, University of IowaIowa City, IA, USA; Department of Anatomy and Cell Biology, University of IowaIowa City, IA, USA
| | - Shu-Chan Hsu
- Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
| | - Charles Yeaman
- Molecular and Cellular Biology Program, University of IowaIowa City, IA, USA; Department of Anatomy and Cell Biology, University of IowaIowa City, IA, USA
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30
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Lu H, Liu S, Zhang G, Kwong LN, Zhu Y, Miller JP, Hu Y, Zhong W, Zeng J, Wu L, Krepler C, Sproesser K, Xiao M, Xu W, Karakousis GC, Schuchter LM, Field J, Zhang PJ, Herlyn M, Xu X, Guo W. Oncogenic BRAF-Mediated Melanoma Cell Invasion. Cell Rep 2016; 15:2012-24. [PMID: 27210749 DOI: 10.1016/j.celrep.2016.04.073] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/21/2016] [Accepted: 04/19/2016] [Indexed: 12/25/2022] Open
Abstract
Melanoma patients with oncogenic BRAF(V600E) mutation have poor prognoses. While the role of BRAF(V600E) in tumorigenesis is well established, its involvement in metastasis that is clinically observed in melanoma patients remains a topic of debate. Here, we show that BRAF(V600E) melanoma cells have extensive invasion activity as assayed by the generation of F-actin and cortactin foci that mediate membrane protrusion, and degradation of the extracellular matrix (ECM). Inhibition of BRAF(V600E) blocks melanoma cell invasion. In a BRAF(V600E)-driven murine melanoma model or in patients' tumor biopsies, cortactin foci decrease upon inhibitor treatment. In addition, genome-wide expression analysis shows that a number of invadopodia-related genes are downregulated after BRAF(V600E) inhibition. Mechanistically, BRAF(V600E) induces phosphorylation of cortactin and the exocyst subunit Exo70 through ERK, which regulates actin dynamics and matrix metalloprotease secretion, respectively. Our results provide support for the role of BRAF(V600E) in metastasis and suggest that inhibiting invasion is a potential therapeutic strategy against melanoma.
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Affiliation(s)
- Hezhe Lu
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shujing Liu
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gao Zhang
- Molecular and Cellular Oncogenesis Program and Melanoma Research Center, The Wistar Institute, Philadelphia, PA 19104, USA
| | - Lawrence N Kwong
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 770303, USA
| | - Yueyao Zhu
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John P Miller
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 770303, USA
| | - Yi Hu
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| | - Wenqun Zhong
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jingwen Zeng
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lawrence Wu
- Molecular and Cellular Oncogenesis Program and Melanoma Research Center, The Wistar Institute, Philadelphia, PA 19104, USA
| | - Clemens Krepler
- Molecular and Cellular Oncogenesis Program and Melanoma Research Center, The Wistar Institute, Philadelphia, PA 19104, USA
| | - Katrin Sproesser
- Molecular and Cellular Oncogenesis Program and Melanoma Research Center, The Wistar Institute, Philadelphia, PA 19104, USA
| | - Min Xiao
- Molecular and Cellular Oncogenesis Program and Melanoma Research Center, The Wistar Institute, Philadelphia, PA 19104, USA
| | - Wei Xu
- Abramson Cancer Center and Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Giorgos C Karakousis
- Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lynn M Schuchter
- Abramson Cancer Center and Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jeffery Field
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul J Zhang
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Meenhard Herlyn
- Molecular and Cellular Oncogenesis Program and Melanoma Research Center, The Wistar Institute, Philadelphia, PA 19104, USA
| | - Xiaowei Xu
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Wei Guo
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA.
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31
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Boateng LR, Bennin D, De Oliveira S, Huttenlocher A. Mammalian Actin-binding Protein-1/Hip-55 Interacts with FHL2 and Negatively Regulates Cell Invasion. J Biol Chem 2016; 291:13987-13998. [PMID: 27129278 DOI: 10.1074/jbc.m116.725739] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Indexed: 11/06/2022] Open
Abstract
Mammalian actin-binding protein-1 (mAbp1) is an adaptor protein that binds actin and modulates scission during endocytosis. Recent studies suggest that mAbp1 impairs cell invasion; however, the mechanism for the inhibitory effects of mAbp1 remain unclear. We performed a yeast two-hybrid screen and identified the adaptor protein, FHL2, as a novel binding partner that interacts with the N-terminal actin depolymerizing factor homology domain (ADFH) domain of mAbp1. Here we report that depletion of mAbp1 or ectopic expression of the ADFH domain of mAbp1 increased Rho GTPase signaling and breast cancer cell invasion. Moreover, cell invasion induced by the ADFH domain of mAbp1 required the expression of FHL2. Taken together, our findings show that mAbp1 and FHL2 are novel binding partners that differentially regulate Rho GTPase signaling and MTLn3 breast cancer cell invasion.
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Affiliation(s)
- Lindsy R Boateng
- Program in Cellular and Molecular Biology, University of Wisconsin, Madison, Wisconsin 53706
| | - David Bennin
- Departments of Medical Microbiology and Immunology and Pediatrics, University of Wisconsin, Madison, Wisconsin 53706
| | - Sofia De Oliveira
- Departments of Medical Microbiology and Immunology and Pediatrics, University of Wisconsin, Madison, Wisconsin 53706
| | - Anna Huttenlocher
- Departments of Medical Microbiology and Immunology and Pediatrics, University of Wisconsin, Madison, Wisconsin 53706.
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32
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Martin-Urdiroz M, Deeks MJ, Horton CG, Dawe HR, Jourdain I. The Exocyst Complex in Health and Disease. Front Cell Dev Biol 2016; 4:24. [PMID: 27148529 PMCID: PMC4828438 DOI: 10.3389/fcell.2016.00024] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/11/2016] [Indexed: 01/23/2023] Open
Abstract
Exocytosis involves the fusion of intracellular secretory vesicles with the plasma membrane, thereby delivering integral membrane proteins to the cell surface and releasing material into the extracellular space. Importantly, exocytosis also provides a source of lipid moieties for membrane extension. The tethering of the secretory vesicle before docking and fusion with the plasma membrane is mediated by the exocyst complex, an evolutionary conserved octameric complex of proteins. Recent findings indicate that the exocyst complex also takes part in other intra-cellular processes besides secretion. These various functions seem to converge toward defining a direction of membrane growth in a range of systems from fungi to plants and from neurons to cilia. In this review we summarize the current knowledge of exocyst function in cell polarity, signaling and cell-cell communication and discuss implications for plant and animal health and disease.
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Affiliation(s)
| | - Michael J Deeks
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Connor G Horton
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Helen R Dawe
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Isabelle Jourdain
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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33
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Cortactin and Exo70 mediated invasion of hepatoma carcinoma cells by MMP-9 secretion. Mol Biol Rep 2016; 43:407-14. [PMID: 27025610 DOI: 10.1007/s11033-016-3972-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/14/2016] [Indexed: 01/11/2023]
Abstract
This study was aimed to evaluate the regulation mechanism of cortactin (CTTN) on matrix metalloproteinases 9 (MMP-9) and its relations with Exo70 in invasion of hepatoma carcinoma (HCC) cells. The expression levels of CTTN, Exo70 and MMP-9 were detected in normal hepatocytes and various HCC cells by real-time PCR. Then the migration and invasion ability of these cells was revealed by scratch and invasion assay. The effects of CTTN on MMP-9 and the ability of migration and invasion were evaluated by silence and overexpress CTTN. During this process, the expression of CTTN was detected by Western blot, the activity and concentration of MMP-9 in supernatant of culture medium was detected by zymography and ELISA assay. Besides, Exo70 was also inhibited to reveal its effects on MMP-9 and the migration and invasion ability of LM3. Increased expression of CTTN, MMP-9, Exo70, reduced scratch area and increased puncture cell numbers were found in HCC cells (p < 0.05). The expression of CTTN was significantly correlated with Exo70 and the migration and invasion ability of HCC (p < 0.05). In addition, the activity and concentration of MMP-9 were significantly affected by the expression level of CTTN, while the expression of MMP-9 was not influenced. Besides, Exo70-si also exhibited significantly inhibition effects on the activity and concentration of MMP-9 and puncture cell numbers (p < 0.05). A synergistic reaction may exhibited on CTTN and Exo70, which could mediate the secretion of MMPs thereby regulate tumor invasion.
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34
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Bravo-Cordero JJ, Cordani M, Soriano SF, Díez B, Muñoz-Agudo C, Casanova-Acebes M, Boullosa C, Guadamillas MC, Ezkurdia I, González-Pisano D, del Pozo MA, Montoya MC. A novel high content analysis tool reveals Rab8-driven actin and FA reorganization through Rho GTPases and calpain/MT1. J Cell Sci 2016; 129:1734-49. [DOI: 10.1242/jcs.174920] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 02/29/2016] [Indexed: 01/31/2023] Open
Abstract
Rab8 is a small Ras-related GTPase that regulates polarized membrane transport to the plasma membrane. A high content analysis (HCA) tool developed to dissect Rab8-mediated actin and focal adhesion (FA) reorganization revealed that Rab8 activation significantly induced Rac1/Tiam1 to mediate cortical actin (CA) formation and RhoA-dependent stress fibre (SF) disassembly. Rab8 activation increased Rac1 activity, while its depletion activated RhoA, which led to reorganization of the actin cytoskeleton. Rab8 was also associated with FA, promoting their disassembly in a microtubule dependent manner. This Rab8 effect involved Calpain, MT1-MMP and Rho GTPases. Moreover, we demonstrate the role of Rab8 in the cell migration process. Indeed, Rab8 is required for EGF-induced cell polarization and chemotaxis as well as for the directional persistency of intrinsic cell motility. These data reveal that Rab8 drives cell motility by mechanisms both dependent and independent of Rho GTPases, thereby regulating the establishment of cell polarity, turnover of FA, and actin cytoskeleton rearrangements, thus determining the directionality of cell migration.
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Affiliation(s)
- José J. Bravo-Cordero
- Current Address: Division of Hematology and Oncology, Department of Medicine, Mount Sinai School of Medicine, Tisch Cancer Institute, New York, NY, Box 1079, USA
| | - Marco Cordani
- Integrin Signaling Laboratory, Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro 3, Madrid, E28029, Spain
| | - Silvia F. Soriano
- Integrin Signaling Laboratory, Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro 3, Madrid, E28029, Spain
| | - Begoña Díez
- Cellomics Unit. Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares CNIC. C/ Melchor Fernandez Almagro, 3. Madrid, E28029, Spain
| | - Carmen Muñoz-Agudo
- Cellomics Unit. Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares CNIC. C/ Melchor Fernandez Almagro, 3. Madrid, E28029, Spain
| | - María Casanova-Acebes
- Cellomics Unit. Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares CNIC. C/ Melchor Fernandez Almagro, 3. Madrid, E28029, Spain
| | - César Boullosa
- Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), C/Melchor Fernández Almagro 3, Madrid E28029, Spain
| | - Marta C. Guadamillas
- Integrin Signaling Laboratory, Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro 3, Madrid, E28029, Spain
| | - Iakes Ezkurdia
- Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), C/Melchor Fernández Almagro 3, Madrid E28029, Spain
| | - David González-Pisano
- Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), C/Melchor Fernández Almagro 3, Madrid E28029, Spain
| | - Miguel A. del Pozo
- Integrin Signaling Laboratory, Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro 3, Madrid, E28029, Spain
| | - María C. Montoya
- Cellomics Unit. Cell Biology & Physiology Program; Cell & Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares CNIC. C/ Melchor Fernandez Almagro, 3. Madrid, E28029, Spain
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Endosidin2 targets conserved exocyst complex subunit EXO70 to inhibit exocytosis. Proc Natl Acad Sci U S A 2015; 113:E41-50. [PMID: 26607451 DOI: 10.1073/pnas.1521248112] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The exocyst complex regulates the last steps of exocytosis, which is essential to organisms across kingdoms. In humans, its dysfunction is correlated with several significant diseases, such as diabetes and cancer progression. Investigation of the dynamic regulation of the evolutionarily conserved exocyst-related processes using mutants in genetically tractable organisms such as Arabidopsis thaliana is limited by the lethality or the severity of phenotypes. We discovered that the small molecule Endosidin2 (ES2) binds to the EXO70 (exocyst component of 70 kDa) subunit of the exocyst complex, resulting in inhibition of exocytosis and endosomal recycling in both plant and human cells and enhancement of plant vacuolar trafficking. An EXO70 protein with a C-terminal truncation results in dominant ES2 resistance, uncovering possible distinct regulatory roles for the N terminus of the protein. This study not only provides a valuable tool in studying exocytosis regulation but also offers a potentially new target for drugs aimed at addressing human disease.
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Peri-implantation lethality in mice carrying megabase-scale deletion on 5qc3.3 is caused by Exoc1 null mutation. Sci Rep 2015; 5:13632. [PMID: 26346620 PMCID: PMC4562154 DOI: 10.1038/srep13632] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/03/2015] [Indexed: 01/28/2023] Open
Abstract
We found a novel spontaneous mouse mutant with depigmentation in the ventral body, which we called White Spotting (WS) mouse. Genetic investigation revealed deletion of a > 1.2-Mb genomic region containing nine genes (Kit, Kdr, Srd5a3, Tmeme165, Clock, Pdcl2, Nmu, Exoc1, and Cep135). We designated this mutant allele KitWS. Interestingly, homozygous mutants (KitWS/WS) showed a peri-implantation lethal phenotype. Expression analyses of these nine genes in blastocysts suggested that Exoc1 was a prime candidate for this phenotype. We produced Exoc1 knockout mice, and the same peri-implantation lethal phenotype was seen in Exoc1−/− embryos. In addition, the polygenic effect without Exoc1 was investigated in genome-edited KitWE mice carrying the Mb-scale deletion induced by the CRISPR/Cas9 system. As KitWE/WE embryos did not exhibit the abnormal phenotype, which was seen in KitWS/WS. We concluded that peri-implantation lethality in KitWS/WS was caused by a monogenic defect of Exoc1.
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Abstract
The exocyst is an octameric protein complex that is implicated in the tethering of secretory vesicles to the plasma membrane prior to SNARE-mediated fusion. Spatial and temporal control of exocytosis through the exocyst has a crucial role in a number of physiological processes, such as morphogenesis, cell cycle progression, primary ciliogenesis, cell migration and tumor invasion. In this Cell Science at a Glance poster article, we summarize recent works on the molecular organization, function and regulation of the exocyst complex, as they provide rationales to the involvement of this complex in such a diverse array of cellular processes.
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Affiliation(s)
- Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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38
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Urothelial Defects from Targeted Inactivation of Exocyst Sec10 in Mice Cause Ureteropelvic Junction Obstructions. PLoS One 2015; 10:e0129346. [PMID: 26046524 PMCID: PMC4457632 DOI: 10.1371/journal.pone.0129346] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/07/2015] [Indexed: 01/12/2023] Open
Abstract
Most cases of congenital obstructive nephropathy are the result of ureteropelvic junction obstructions, and despite their high prevalence, we have a poor understanding of their etiology and scarcity of genetic models. The eight-protein exocyst complex regulates polarized exocytosis of intracellular vesicles in a large variety of cell types. Here we report generation of a conditional knockout mouse for Sec10, a central component of the exocyst, which is the first conditional allele for any exocyst gene. Inactivation of Sec10 in ureteric bud-derived cells using Ksp1.3-Cre mice resulted in severe bilateral hydronephrosis and complete anuria in newborns, with death occurring 6-14 hours after birth. Sec10 FL/FL;Ksp-Cre embryos developed ureteropelvic junction obstructions between E17.5 and E18.5 as a result of degeneration of the urothelium and subsequent overgrowth by surrounding mesenchymal cells. The urothelial cell layer that lines the urinary tract must maintain a hydrophobic luminal barrier again urine while remaining highly stretchable. This barrier is largely established by production of uroplakin proteins that are transported to the apical surface to establish large plaques. By E16.5, Sec10 FL/FL;Ksp-Cre ureter and pelvic urothelium showed decreased uroplakin-3 protein at the luminal surface, and complete absence of uroplakin-3 by E17.5. Affected urothelium at the UPJ showed irregular barriers that exposed the smooth muscle layer to urine, suggesting this may trigger the surrounding mesenchymal cells to overgrow the lumen. Findings from this novel mouse model show Sec10 is critical for the development of the urothelium in ureters, and provides experimental evidence that failure of this urothelial barrier may contribute to human congenital urinary tract obstructions.
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Shirakawa R, Horiuchi H. Ral GTPases: crucial mediators of exocytosis and tumourigenesis. J Biochem 2015; 157:285-99. [DOI: 10.1093/jb/mvv029] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/07/2015] [Indexed: 11/12/2022] Open
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Inoue M, Akama T, Jiang Y, Chun TH. The exocyst complex regulates free fatty acid uptake by adipocytes. PLoS One 2015; 10:e0120289. [PMID: 25768116 PMCID: PMC4359155 DOI: 10.1371/journal.pone.0120289] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 02/03/2015] [Indexed: 11/19/2022] Open
Abstract
The exocyst is an octameric molecular complex that drives vesicle trafficking in adipocytes, a rate-limiting step in insulin-dependent glucose uptake. This study assessed the role of the exocyst complex in regulating free fatty acid (FFA) uptake by adipocytes. Upon differentiating into adipocytes, 3T3-L1 cells acquire the ability to incorporate extracellular FFAs in an insulin-dependent manner. A kinetic assay using fluoresceinated FFA (C12 dodecanoic acid) uptake allows the real-time monitoring of FFA internalization by adipocytes. The insulin-dependent uptake of C12 dodecanoic acid by 3T3-L1 adipocytes is mediated by Akt and phosphatidylinositol 3 (PI3)-kinase. Gene silencing of the exocyst components Exo70 and Sec8 significantly reduced insulin-dependent FFA uptake by adipocytes. Consistent with the roles played by Exo70 and Sec8 in FFA uptake, mCherry-tagged Exo70 and HA-tagged Sec8 partially colocalize with lipid droplets within adipocytes, suggesting their active roles in the development of lipid droplets. Tubulin polymerization was also found to regulate FFA uptake in collaboration with the exocyst complex. This study demonstrates a novel role played by the exocyst complex in the regulation of FFA uptake by adipocytes.
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Affiliation(s)
- Mayumi Inoue
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Takeshi Akama
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Yibin Jiang
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Tae-Hwa Chun
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
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Valenzuela-Iglesias A, Sharma VP, Beaty BT, Ding Z, Gutierrez-Millan LE, Roy P, Condeelis JS, Bravo-Cordero JJ. Profilin1 regulates invadopodium maturation in human breast cancer cells. Eur J Cell Biol 2015; 94:78-89. [PMID: 25613364 PMCID: PMC4322761 DOI: 10.1016/j.ejcb.2014.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 12/08/2014] [Accepted: 12/17/2014] [Indexed: 01/23/2023] Open
Abstract
Invadopodia are actin-driven membrane protrusions that show oscillatory assembly and disassembly causing matrix degradation to support invasion and dissemination of cancer cells in vitro and in vivo. Profilin1, an actin and phosphoinositide binding protein, is downregulated in several adenocarcinomas and it is been shown that its depletion enhances invasiveness and motility of breast cancer cells by increasing PI(3,4)P2 levels at the leading edge. In this study, we show for the first time that depletion of profilin1 leads to an increase in the number of mature invadopodia and these assemble and disassemble more rapidly than in control cells. Previous work by Sharma et al. (2013a), has shown that the binding of the protein Tks5 with PI(3,4)P2 confers stability to the invadopodium precursor causing it to mature into a degradation-competent structure. We found that loss of profilin1 expression increases the levels of PI(3,4)P2 at the invadopodium and as a result, enhances recruitment of the interacting adaptor Tks5. The increased PI(3,4)P2-Tks5 interaction accelerates the rate of invadopodium anchorage, maturation, and turnover. Our results indicate that profilin1 acts as a molecular regulator of the levels of PI(3,4)P2 and Tks5 recruitment in invadopodia to control the invasion efficiency of invadopodia.
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Affiliation(s)
- A Valenzuela-Iglesias
- Department of Scientific and Technological Research DICTUS, University of Sonora, Hermosillo, Mexico.
| | - V P Sharma
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, United States; Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, United States
| | - B T Beaty
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, United States
| | - Z Ding
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - L E Gutierrez-Millan
- Department of Scientific and Technological Research DICTUS, University of Sonora, Hermosillo, Mexico
| | - P Roy
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Department of Pathology, University of Pittsburgh, Pittsburgh, PA, United States
| | - J S Condeelis
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, United States; Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, United States.
| | - J J Bravo-Cordero
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, United States; Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, United States.
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42
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Involvement of RalB in the effect of geranylgeranyltransferase I on glioma cell migration and invasion. Clin Transl Oncol 2015; 17:477-85. [DOI: 10.1007/s12094-014-1263-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/30/2014] [Indexed: 10/24/2022]
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Havrylov S, Park M. MS/MS-based strategies for proteomic profiling of invasive cell structures. Proteomics 2014; 15:272-86. [PMID: 25303514 DOI: 10.1002/pmic.201400220] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/19/2014] [Accepted: 10/01/2014] [Indexed: 12/29/2022]
Abstract
Acquired capacity of cancer cells to penetrate through the extracellular matrix of surrounding tissues is a prerequisite for tumour metastatic spread - the main source of cancer-associated mortality. Through combined efforts of many research groups, we are beginning to understand that the ability of cells to invade through the extracellular matrix is a multi-faceted phenomenon supported by variety of specialised protrusive cellular structures, primarily pseudopodia, invadopodia and podosomes. Additionally, secreted extracellular vesicles are being increasingly recognised as important mediators of invasive cell phenotypes and therefore may be considered bona fide invasive cell structures. Dissection of the molecular makings underlying biogenesis and function of all of these structures is crucial to identify novel targets for specific anti-metastatic therapies. Rapid advances and growing accessibility of MS/MS-based protein identification made this family of techniques a suitable and appropriate choice for proteomic profiling of invasive cell structures. In this review, we provide a summary of current progress in the characterisation of protein composition and topology of protein interaction networks of pseudopodia, invadopodia, podosomes and extracellular vesicles, as well as outline challenges and perspectives of the field.
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Affiliation(s)
- Serhiy Havrylov
- Goodman Cancer Research Centre, McGill University, Montreal, QC, Canada; Department of Medicine, McGill University, Montreal, QC, Canada
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44
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Fernandes MC, Corrotte M, Miguel DC, Tam C, Andrews NW. The exocyst is required for trypanosome invasion and the repair of mechanical plasma membrane wounds. J Cell Sci 2014; 128:27-32. [PMID: 25380822 DOI: 10.1242/jcs.150573] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The process of host cell invasion by Trypanosoma cruzi shares mechanistic elements with plasma membrane injury and repair. Both processes require Ca(2+)-triggered exocytosis of lysosomes, exocytosis of acid sphingomyelinase and formation of ceramide-enriched endocytic compartments. T. cruzi invades at peripheral sites, suggesting a need for spatial regulation of membrane traffic. Here, we show that Exo70 and Sec8 (also known as EXOC7 and EXOC4, respectively), components of the exocyst complex, accumulate in nascent T. cruzi vacuoles and at sites of mechanical wounding. Exo70 or Sec8 depletion inhibits T. cruzi invasion and Ca(2+)-dependent resealing of mechanical wounds, but does not affect the repair of smaller lesions caused by pore-forming toxins. Thus, T. cruzi invasion and mechanical lesion repair share a unique requirement for the exocyst, consistent with a dependence on targeted membrane delivery.
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Affiliation(s)
- Maria Cecilia Fernandes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742-5815, USA
| | - Matthias Corrotte
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742-5815, USA
| | - Danilo C Miguel
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742-5815, USA
| | - Christina Tam
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742-5815, USA
| | - Norma W Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742-5815, USA
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45
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Tanaka T, Iino M, Goto K. Knockdown of Sec8 enhances the binding affinity of c-Jun N-terminal kinase (JNK)-interacting protein 4 for mitogen-activated protein kinase kinase 4 (MKK4) and suppresses the phosphorylation of MKK4, p38, and JNK, thereby inhibiting apoptosis. FEBS J 2014; 281:5237-50. [PMID: 25244576 DOI: 10.1111/febs.13063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 09/15/2014] [Accepted: 09/18/2014] [Indexed: 01/19/2023]
Abstract
The exocyst complex, also called the Sec6/8 complex, is important for targeting exocytic vesicles to specific docking sites on the plasma membrane in yeast and mammalian cells. In addition to these original findings, recent results of studies suggest that Sec8 is also involved in oncogenesis, although the functional implications of Sec8 in cancer cells are not well understood. c-Jun N-terminal kinase-interacting protein 4 (JIP4) is a scaffold protein that plays a crucial role in the regulation of mitogen-activated protein kinase (MAPK) signaling cascades. The present study examined how Sec8 is involved in JIP4-mediated MAPK signaling under apoptotic conditions. It was found that Sec8 binds to and regulates JIP4, and that knockdown of Sec8 enhances the binding of JIP4 to MAPK kinase 4, thereby decreasing the phosphorylation of MAPK kinase 4, JNK, and p38. These results raise the possibility that Sec8 serves as an important regulator of MAPK signaling cascades.
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Affiliation(s)
- Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Japan; Department of Dentistry, Oral and Maxillofacial Surgery, Plastic and Reconstructive Surgery, Yamagata University School of Medicine, Japan
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46
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Yu S, Yehia G, Wang J, Stypulkowski E, Sakamori R, Jiang P, Hernandez-Enriquez B, Tran TS, Bonder EM, Guo W, Gao N. Global ablation of the mouse Rab11a gene impairs early embryogenesis and matrix metalloproteinase secretion. J Biol Chem 2014; 289:32030-32043. [PMID: 25271168 DOI: 10.1074/jbc.m113.538223] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Rab11a has been conceived as a prominent regulatory component of the recycling endosome, which acts as a nexus in the endo- and exocytotic networks. The precise in vivo role of Rab11a in mouse embryonic development is unknown. We globally ablated Rab11a and examined the phenotypic and molecular outcomes in Rab11a(null) blastocysts and mouse embryonic fibroblasts. Using multiple trafficking assays and complementation analyses, we determined, among multiple important membrane-associated and soluble cargos, the critical contribution of Rab11a vesicular traffic to the secretion of multiple soluble MMPs. Rab11a(null) embryos were able to properly form normal blastocysts but died at peri-implantation stages. Our data suggest that Rab11a critically controls mouse blastocyst development and soluble matrix metalloproteinase secretion.
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Affiliation(s)
- Shiyan Yu
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Ghassan Yehia
- Transgenic Core Facility, Rutgers New Jersey Medical School, Newark, New Jersey 07103
| | - Juanfei Wang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Ewa Stypulkowski
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Ryotaro Sakamori
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Ping Jiang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | | | - Tracy S Tran
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Edward M Bonder
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102,.
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47
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Luo G, Zhang J, Guo W. The role of Sec3p in secretory vesicle targeting and exocyst complex assembly. Mol Biol Cell 2014; 25:3813-22. [PMID: 25232005 PMCID: PMC4230786 DOI: 10.1091/mbc.e14-04-0907] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The exocyst has been speculated to mediate the tethering of secretory vesicles to the plasma membrane. However, there has been no direct experimental evidence for this notion. An ectopic targeting strategy is used to provide experimental support for this model and investigate the regulators of exocyst assembly and vesicle targeting. During membrane trafficking, vesicular carriers are transported and tethered to their cognate acceptor compartments before soluble N-ethylmaleimide–sensitive factor attachment protein (SNARE)-mediated membrane fusion. The exocyst complex was believed to target and tether post-Golgi secretory vesicles to the plasma membrane during exocytosis. However, no definitive experimental evidence is available to support this notion. We developed an ectopic targeting assay in yeast in which each of the eight exocyst subunits was expressed on the surface of mitochondria. We find that most of the exocyst subunits were able to recruit the other members of the complex there, and mistargeting of the exocyst led to secretion defects in cells. On the other hand, only the ectopically located Sec3p subunit is capable of recruiting secretory vesicles to mitochondria. Our assay also suggests that both cytosolic diffusion and cytoskeleton-based transport mediate the recruitment of exocyst subunits and secretory vesicles during exocytosis. In addition, the Rab GTPase Sec4p and its guanine nucleotide exchange factor Sec2p regulate the assembly of the exocyst complex. Our study helps to establish the role of the exocyst subunits in tethering and allows the investigation of the mechanisms that regulate vesicle tethering during exocytosis.
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Affiliation(s)
- Guangzuo Luo
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018
| | - Jian Zhang
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018
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48
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Monteiro P, Rossé C, Castro-Castro A, Irondelle M, Lagoutte E, Paul-Gilloteaux P, Desnos C, Formstecher E, Darchen F, Perrais D, Gautreau A, Hertzog M, Chavrier P. Endosomal WASH and exocyst complexes control exocytosis of MT1-MMP at invadopodia. ACTA ACUST UNITED AC 2014; 203:1063-79. [PMID: 24344185 PMCID: PMC3871436 DOI: 10.1083/jcb.201306162] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
WASH and exocyst promote pericellular matrix degradation and tumor cell invasion by enabling localized exocytosis of MT1-MMP from late endosomes. Remodeling of the extracellular matrix by carcinoma cells during metastatic dissemination requires formation of actin-based protrusions of the plasma membrane called invadopodia, where the trans-membrane type 1 matrix metalloproteinase (MT1-MMP) accumulates. Here, we describe an interaction between the exocyst complex and the endosomal Arp2/3 activator Wiskott-Aldrich syndrome protein and Scar homolog (WASH) on MT1-MMP–containing late endosomes in invasive breast carcinoma cells. We found that WASH and exocyst are required for matrix degradation by an exocytic mechanism that involves tubular connections between MT1-MMP–positive late endosomes and the plasma membrane in contact with the matrix. This ensures focal delivery of MT1-MMP and supports pericellular matrix degradation and tumor cell invasion into different pathologically relevant matrix environments. Our data suggest a general mechanism used by tumor cells to breach the basement membrane and for invasive migration through fibrous collagen-enriched tissues surrounding the tumor.
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49
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Exo70 isoform switching upon epithelial-mesenchymal transition mediates cancer cell invasion. Dev Cell 2014; 27:560-73. [PMID: 24331928 DOI: 10.1016/j.devcel.2013.10.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 07/31/2013] [Accepted: 10/28/2013] [Indexed: 02/06/2023]
Abstract
Epithelial-mesenchymal transition (EMT) is an important developmental process hijacked by cancer cells for their dissemination. Here, we show that Exo70, a component of the exocyst complex, undergoes isoform switching mediated by ESRP1, a pre-mRNA splicing factor that regulates EMT. Expression of the epithelial isoform of Exo70 affects the levels of key EMT transcriptional regulators such as Snail and ZEB2 and is sufficient to drive the transition to epithelial phenotypes. Differential Exo70 isoform expression in human tumors correlates with cancer progression, and increased expression of the epithelial isoform of Exo70 inhibits tumor metastasis in mice. At the molecular level, the mesenchymal-but not the epithelial-isoform of Exo70 interacts with the Arp2/3 complex and stimulates actin polymerization for tumor invasion. Our findings provide a mechanism by which the exocyst function and actin dynamics are modulated for EMT and tumor invasion.
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50
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Das A, Gajendra S, Falenta K, Oudin MJ, Peschard P, Feng S, Wu B, Marshall CJ, Doherty P, Guo W, Lalli G. RalA promotes a direct exocyst-Par6 interaction to regulate polarity in neuronal development. J Cell Sci 2014; 127:686-99. [PMID: 24284074 PMCID: PMC4007768 DOI: 10.1242/jcs.145037] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 11/05/2013] [Indexed: 01/25/2023] Open
Abstract
Cell polarization is essential for neuronal development in both the embryonic and postnatal brain. Here, using primary cultures, in vivo postnatal electroporation and conditional genetic ablation, we show that the Ras-like small GTPase RalA and its effector, the exocyst, regulate the morphology and polarized migration of neural progenitors derived from the subventricular zone, a major neurogenic niche in the postnatal brain. Active RalA promotes the direct binding between the exocyst subunit Exo84 and the PDZ domain of Par6 through a non-canonical PDZ-binding motif. Blocking the Exo84-Par6 interaction impairs polarization in postnatal neural progenitors and cultured embryonic neurons. Our results provide the first in vivo characterization of RalA function in the mammalian brain and highlight a novel molecular mechanism for cell polarization. Given that the exocyst and the Par complex are conserved in many tissues, the functional significance of their interaction and its regulation by RalA are likely to be important in a wide range of polarization events.
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Affiliation(s)
- Amlan Das
- University of Pennsylvania Department of Biology, Philadelphia, PA 19104, USA
| | - Sangeetha Gajendra
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Katarzyna Falenta
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Madeleine J. Oudin
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Pascal Peschard
- The Institute of Cancer Research, Division of Cancer Cell Biology, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
| | - Shanshan Feng
- University of Pennsylvania Department of Biology, Philadelphia, PA 19104, USA
| | - Bin Wu
- University of Pennsylvania Department of Biology, Philadelphia, PA 19104, USA
| | - Christopher J. Marshall
- The Institute of Cancer Research, Division of Cancer Cell Biology, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
| | - Patrick Doherty
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Wei Guo
- University of Pennsylvania Department of Biology, Philadelphia, PA 19104, USA
| | - Giovanna Lalli
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
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