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Lv S, Chen Z, Mi H, Yu X. Cofilin Acts as a Booster for Progression of Malignant Tumors Represented by Glioma. Cancer Manag Res 2022; 14:3245-3269. [PMID: 36452435 PMCID: PMC9703913 DOI: 10.2147/cmar.s389825] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/10/2022] [Indexed: 07/20/2023] Open
Abstract
Cofilin, as a depolymerization factor of actin filaments, has been widely studied. Evidences show that cofilin has a role in actin structural reorganization and dynamic regulation. In recent years, several studies have demonstrated a regulatory role for cofilin in the migration and invasion mediated by cell dynamics and epithelial to mesenchymal transition (EMT)/EMT-like process, apoptosis, radiotherapy resistance, immune escape, and transcriptional dysregulation of malignant tumor cells, particularly glioma cells. On this basis, it is practical to evaluate cofilin as a biomarker for predicting tumor metastasis and prognosis. Targeting cofilin regulating kinases, Lin11, Isl-1 and Mec-3 kinases (LIM kinases/LIMKs) and their major upstream molecules inhibits tumor cell migration and invasion and targeting cofilin-mediated mitochondrial pathway induces apoptosis of tumor cells represent effective options for the development of novel anti-malignant tumor drug, especially anti-glioma drugs. This review explores the structure, general biological function, and regulation of cofilin, with an emphasis on the critical functions and prospects for clinical therapeutic applications of cofilin in malignant tumors represented by glioma.
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Affiliation(s)
- Shihong Lv
- Department of Gastroenterology, The Second Affiliated Hospital of Mudanjiang Medical College, Mudanjiang Medical College, Mudanjiang, 157011, People’s Republic of China
| | - Zhiye Chen
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People’s Republic of China
- Department of Histology and Embryology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People’s Republic of China
| | - Hailong Mi
- Department of Histology and Embryology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People’s Republic of China
| | - Xingjiang Yu
- Department of Histology and Embryology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People’s Republic of China
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2
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Chen C, Maimaiti Y, Zhijun S, Zeming L, Yawen G, Pan Y, Tao H. Slingshot-1L, a cofilin phosphatase, induces primary breast cancer metastasis. Oncotarget 2017; 8:66195-66203. [PMID: 29029503 PMCID: PMC5630403 DOI: 10.18632/oncotarget.19855] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/28/2017] [Indexed: 01/06/2023] Open
Abstract
Slingshot (SSH) is a member of the conserved family of cofilin phosphatases that plays a critical role in cell membrane protrusion and migration by transforming inactive phosphorylated cofilin to an active form. SSH-like protein 1 (SSH-1L) expression is detected in various types of tumors; insulin induces the phosphatases activity of SSH-1L in a phosphoinositide 3-kinase-dependent manner. However, little is known about the expression and role of SSH-1L in breast cancer. Here, we analyzed 295 human breast cancer tissue specimens for SSH-1L expression by immunohistochemistry. The correlation between SSH-1L level and patients' clinical characteristics was analyzed with Pearson's χ2 test. The function of SSH-1L was evaluated by gene knockdown and quantitative real-time polymerase chain reaction detection of cofilin expression in MDA-MB-231, MCF-7, and SK-BR-3 human breast cancer cell lines. SSH-1L expression was detected in 88.1% of tissue specimens by immunohistochemistry and was strongly associated with increased metastasis and mortality. Loss of SSH-1L expression decreased the nonphosphorylated, active form of cofilin in SK-BR-3 and MDA-MB-231 cell lines, which was associated with reduced cell motility. Accordingly, SSH-1L/cofilin signaling played a critical role in primary breast cancer metastasis and was a potential therapeutic target for breast cancer treatment.
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Affiliation(s)
- Chen Chen
- Department of Breast and Thyroid Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Yusufu Maimaiti
- Department of General Surgery (Research Institute of Minimally Invasive), People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi 830000, P.R. China
| | - Shen Zhijun
- Clinical Laboratory, The Third People's Hospital of Hubei Province, Wuhan 430000, P.R. China
| | - Liu Zeming
- Department of Breast and Thyroid Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Guo Yawen
- Department of Breast and Thyroid Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Yu Pan
- Department of Breast and Thyroid Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Huang Tao
- Department of Breast and Thyroid Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
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Takahashi K, Okabe H, Kanno SI, Nagai T, Mizuno K. A pleckstrin homology-like domain is critical for F-actin binding and cofilin-phosphatase activity of Slingshot-1. Biochem Biophys Res Commun 2016; 482:686-692. [PMID: 27865840 DOI: 10.1016/j.bbrc.2016.11.095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 11/15/2016] [Indexed: 11/30/2022]
Abstract
Slingshot-1 (SSH1) is a protein phosphatase that specifically dephosphorylates and activates cofilin, an F-actin-severing protein. SSH1 binds to and co-localizes with F-actin, and the cofilin-phosphatase activity of SSH1 is markedly increased by binding to F-actin. In this study, we performed a secondary structure analysis of SSH1, which predicted the existence of a pleckstrin homology (PH)-like domain in the N-terminal region of SSH1. SSH1 also contains a DEK-C domain in the N-terminal region. The N-terminal fragment of SSH1 bound to and co-localized with F-actin, but mutation at Arg-96 or a Leu-His-Lys (LHK) motif in the PH-like domain reduced this activity. Furthermore, mutation at Arg-96 abrogated the cofilin-phosphatase activity of SSH1 in the presence of F-actin. These results suggest that the N-terminal PH-like domain plays a critical role in F-actin binding and F-actin-mediated activation of the cofilin-phosphatase activity of SSH1.
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Affiliation(s)
- Katsunori Takahashi
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Haruka Okabe
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Shin-Ichiro Kanno
- Division of Dynamic Proteome in Cancer and Aging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan
| | - Tomoaki Nagai
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kensaku Mizuno
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.
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4
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Chen SM, Chen XM, Lu YL, Liu B, Jiang M, Ma YX. Cofilin is correlated with sperm quality and influences sperm fertilizing capacity in humans. Andrology 2016; 4:1064-1072. [PMID: 27369112 DOI: 10.1111/andr.12239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 02/05/2023]
Affiliation(s)
- S. M. Chen
- Department of Medical Genetics; West China Hospital; Sichuan University; Chengdu Sichuan China
- Human Sperm Bank; West China Second University Hospital; Sichuan University; Chengdu Sichuan China
| | - X. M. Chen
- Department of Medical Genetics; West China Hospital; Sichuan University; Chengdu Sichuan China
- Department of Laboratory Medicine; Sichuan Provincial Hospital for Women and Children; Chengdu Sichuan China
| | - Y. L. Lu
- Department of Medical Genetics; West China Hospital; Sichuan University; Chengdu Sichuan China
| | - B. Liu
- Human Sperm Bank; West China Second University Hospital; Sichuan University; Chengdu Sichuan China
| | - M. Jiang
- Human Sperm Bank; West China Second University Hospital; Sichuan University; Chengdu Sichuan China
| | - Y. X. Ma
- Department of Medical Genetics; West China Hospital; Sichuan University; Chengdu Sichuan China
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Wang Y, Kuramitsu Y, Kitagawa T, Baron B, Yoshino S, Maehara SI, Maehara Y, Oka M, Nakamura K. Cofilin-phosphatase slingshot-1L (SSH1L) is over-expressed in pancreatic cancer (PC) and contributes to tumor cell migration. Cancer Lett 2015; 360:171-6. [PMID: 25684665 DOI: 10.1016/j.canlet.2015.02.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 01/31/2015] [Accepted: 02/03/2015] [Indexed: 01/22/2023]
Abstract
Slingshot-1L (SSH1L), a cofilin-phosphatase, plays a role in actin dynamics and cell migration by reactivating cofilin-1. However, the expression of SSH1L in malignant diseases is poorly understood. The overexpression of SSH1L in cancerous tissue compared to the matched surrounding non-cancerous tissues from patients with late stages (III-IV) of PC was detected in 90% (9/10) of cases by western blotting. The expression of SSH1L was shown to be upregulated in tumor cells from 10.7% (11/102) of patients with pancreatic cancer (PC) by immunohistochemistry (IHC). The positive rate of SSH1L in patients with PC at stage VI (TNM) categorized as grade 3 was of 50% (2/4) and 15% (6/40), respectively. Moreover, SSH1L expression was shown to be up-regulated in the PC cell lines (KLM1, PANC-1 and MIAPaCa-2) with high metastatic potential. Loss of SSH1L expression was associated with an increase in the phosphorylation of cofilin-1 at serine-3 and further inhibited cell migration (but not proliferation) in KLM1, PANC-1 and MIAPaCa-2. Actin polymerization inhibitor cytochalasin-D was sufficient to abrogate cell migration of PC without changing SSH1L expression. These results reveal that SSH1L is upregulated in a subset of PCs and that the SSH1L/cofilin-1 signal pathway is associated positively in PC with cell migration. Our study may thus provide potential targets to prevent and/or treat PC invasion and metastasis in patients with SSH1L-positive PC.
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Affiliation(s)
- Yufeng Wang
- Departments of Biochemistry and Functional Proteomics, Digestive Surgery of Applied Molecular Bioscience, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Yasuhiro Kuramitsu
- Departments of Biochemistry and Functional Proteomics, Digestive Surgery of Applied Molecular Bioscience, Yamaguchi University Graduate School of Medicine, Ube, Japan.
| | - Takao Kitagawa
- Departments of Biochemistry and Functional Proteomics, Digestive Surgery of Applied Molecular Bioscience, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Byron Baron
- Departments of Biochemistry and Functional Proteomics, Digestive Surgery of Applied Molecular Bioscience, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Shigefumi Yoshino
- Digestive Surgery of Applied Molecular Bioscience, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Shin-Ichiro Maehara
- Department of Surgery and Science, Graduate School of Medical Science, Kyusyu University, 3-1-1 Maidashi Higashiku, Fukuokashi, Fukuoka, Japan
| | - Yoshihiko Maehara
- Department of Surgery and Science, Graduate School of Medical Science, Kyusyu University, 3-1-1 Maidashi Higashiku, Fukuokashi, Fukuoka, Japan
| | - Masaaki Oka
- Digestive Surgery of Applied Molecular Bioscience, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Kazuyuki Nakamura
- Departments of Biochemistry and Functional Proteomics, Digestive Surgery of Applied Molecular Bioscience, Yamaguchi University Graduate School of Medicine, Ube, Japan; Centre of Clinical Laboratories, Tokuyama Medical Association Hospital, Shunan, Japan
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Torres-Machorro AL, Aris JP, Pillus L. A moonlighting metabolic protein influences repair at DNA double-stranded breaks. Nucleic Acids Res 2015; 43:1646-58. [PMID: 25628362 PMCID: PMC4330366 DOI: 10.1093/nar/gku1405] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Catalytically active proteins with divergent dual functions are often described as ‘moonlighting’. In this work we characterize a new, chromatin-based function of Lys20, a moonlighting protein that is well known for its role in metabolism. Lys20 was initially described as homocitrate synthase (HCS), the first enzyme in the lysine biosynthetic pathway in yeast. Its nuclear localization led to the discovery of a key role for Lys20 in DNA damage repair through its interaction with the MYST family histone acetyltransferase Esa1. Overexpression of Lys20 promotes suppression of DNA damage sensitivity of esa1 mutants. In this work, by taking advantage of LYS20 mutants that are active in repair but not in lysine biosynthesis, the mechanism of suppression of esa1 was characterized. First we analyzed the chromatin landscape of esa1 cells, finding impaired histone acetylation and eviction. Lys20 was recruited to sites of DNA damage, and its overexpression promoted enhanced recruitment of the INO80 remodeling complex to restore normal histone eviction at the damage sites. This study improves understanding of the evolutionary, structural and biological relevance of independent activities in a moonlighting protein and links metabolism to DNA damage repair.
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Affiliation(s)
- Ana Lilia Torres-Machorro
- Section of Molecular Biology, Division of Biological Sciences, UC San Diego Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0347, USA
| | - John P Aris
- Department of Anatomy and Cell Biology, Health Science Center, University of Florida, Gainesville, FL 32610-0235, USA
| | - Lorraine Pillus
- Section of Molecular Biology, Division of Biological Sciences, UC San Diego Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0347, USA
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Abe T, Yamazaki D, Murakami S, Hiroi M, Nitta Y, Maeyama Y, Tabata T. The NAV2 homolog Sickie regulates F-actin-mediated axonal growth in Drosophila mushroom body neurons via the non-canonical Rac-Cofilin pathway. Development 2014; 141:4716-28. [DOI: 10.1242/dev.113308] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Rac-Cofilin pathway is essential for cytoskeletal remodeling to control axonal development. Rac signals through the canonical Rac-Pak-LIMK pathway to suppress Cofilin-dependent axonal growth and through a Pak-independent non-canonical pathway to promote outgrowth. Whether this non-canonical pathway converges to promote Cofilin-dependent F-actin reorganization in axonal growth remains elusive. We demonstrate that Sickie, a homolog of the human microtubule-associated protein neuron navigator 2, cell-autonomously regulates axonal growth of Drosophila mushroom body (MB) neurons via the non-canonical pathway. Sickie was prominently expressed in the newborn F-actin-rich axons of MB neurons. A sickie mutant exhibited axonal growth defects, and its phenotypes were rescued by exogenous expression of Sickie. We observed phenotypic similarities and genetic interactions among sickie and Rac-Cofilin signaling components. Using the MARCM technique, distinct F-actin and phospho-Cofilin patterns were detected in developing axons mutant for sickie and Rac-Cofilin signaling regulators. The upregulation of Cofilin function alleviated the axonal defect of the sickie mutant. Epistasis analyses revealed that Sickie suppresses the LIMK overexpression phenotype and is required for Pak-independent Rac1 and Slingshot phosphatase to counteract LIMK. We propose that Sickie regulates F-actin-mediated axonal growth via the non-canonical Rac-Cofilin pathway in a Slingshot-dependent manner.
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Affiliation(s)
- Takashi Abe
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
- Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Daisuke Yamazaki
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Satoshi Murakami
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Makoto Hiroi
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Yohei Nitta
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Yuko Maeyama
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Tetsuya Tabata
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
- Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
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8
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Takahashi K, Kanno SI, Mizuno K. Activation of cytosolic Slingshot-1 phosphatase by gelsolin-generated soluble actin filaments. Biochem Biophys Res Commun 2014; 454:471-7. [DOI: 10.1016/j.bbrc.2014.10.108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 10/21/2014] [Indexed: 12/15/2022]
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9
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Bielig H, Lautz K, Braun PR, Menning M, Machuy N, Brügmann C, Barisic S, Eisler SA, Andree M, Zurek B, Kashkar H, Sansonetti PJ, Hausser A, Meyer TF, Kufer TA. The cofilin phosphatase slingshot homolog 1 (SSH1) links NOD1 signaling to actin remodeling. PLoS Pathog 2014; 10:e1004351. [PMID: 25187968 PMCID: PMC4154870 DOI: 10.1371/journal.ppat.1004351] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 07/15/2014] [Indexed: 01/01/2023] Open
Abstract
NOD1 is an intracellular pathogen recognition receptor that contributes to anti-bacterial innate immune responses, adaptive immunity and tissue homeostasis. NOD1-induced signaling relies on actin remodeling, however, the details of the connection of NOD1 and the actin cytoskeleton remained elusive. Here, we identified in a druggable-genome wide siRNA screen the cofilin phosphatase SSH1 as a specific and essential component of the NOD1 pathway. We show that depletion of SSH1 impaired pathogen induced NOD1 signaling evident from diminished NF-κB activation and cytokine release. Chemical inhibition of actin polymerization using cytochalasin D rescued the loss of SSH1. We further demonstrate that NOD1 directly interacted with SSH1 at F-actin rich sites. Finally, we show that enhanced cofilin activity is intimately linked to NOD1 signaling. Our data thus provide evidence that NOD1 requires the SSH1/cofilin network for signaling and to detect bacterial induced changes in actin dynamics leading to NF-κB activation and innate immune responses.
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Affiliation(s)
- Harald Bielig
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Katja Lautz
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Peter R. Braun
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Steinbeis-Innovationszentrum Center for Systems Biomedicine, Falkensee, Germany
| | - Maureen Menning
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Nikolaus Machuy
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Christine Brügmann
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Sandra Barisic
- Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany
| | - Stephan A. Eisler
- Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany
| | - Maria Andree
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Birte Zurek
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Hamid Kashkar
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Philippe J. Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- INSERM U786, Institut Pasteur, Paris, France
- Microbiologie et Maladies Infectieuses, Collège de France, Paris, France
| | - Angelika Hausser
- Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany
| | - Thomas F. Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Thomas A. Kufer
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
- University of Hohenheim, Institute of Nutritional Medicine, Stuttgart, Germany
- * E-mail:
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Veit F, Pak O, Egemnazarov B, Roth M, Kosanovic D, Seimetz M, Sommer N, Ghofrani HA, Seeger W, Grimminger F, Brandes RP, Schermuly RT, Weissmann N. Function of NADPH oxidase 1 in pulmonary arterial smooth muscle cells after monocrotaline-induced pulmonary vascular remodeling. Antioxid Redox Signal 2013; 19:2213-31. [PMID: 23706097 DOI: 10.1089/ars.2012.4904] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
AIMS Chronic hypoxia induces pulmonary hypertension (PH) that is concomitant with pulmonary vascular remodeling. Reactive oxygen species (ROS) are thought to play a major role in this. Recent findings suggest that ROS production by NADPH oxidase 4 (Nox4) is important in this remodeling. We investigated whether ROS production by Nox is also important in an inflammatory model of monocrotaline (MCT)-induced PH. We examined ROS production, their possible sources, and their impact on the function of pulmonary arterial smooth muscle cells (PASMC) isolated from MCT-treated and healthy rats. RESULTS MCT-PASMC showed increased intracellular superoxide production, migration, and proliferation compared with healthy controls due to increased Nox1 expression. A comparison of PASMC from MCT- and nontreated rats revealed an up-regulation of Sod2, Nrf2, cyclin D1, and matrix metalloproteinase-9 (MMP-9) as well as an increased phosphorylation of cofilin and extracellular signal-regulated kinases (Erk). Expression of Sod2, Nrf2, and cyclin D1 and phosphorylation of cofilin and Erk were Nox1 dependent. INNOVATION The role of ROS in PH is not fully understood. Mitochondria and Nox have been suggested as sources of altered ROS generation in PH, yet it remains unclear whether increased or decreased ROS contributes to the development of PH. Our studies provide evidence that for different triggers of PH, different Nox isoforms regulate proliferation and migration of PASMC. CONCLUSION In contrast to hypoxia-induced PH, Nox1 but not Nox4 is responsible for pathophysiological proliferation and migration of PASMC in an inflammatory model of MCT-induced PH via increased superoxide production. Thus, different Nox isoforms may be targeted in different forms of PH.
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Affiliation(s)
- Florian Veit
- 1 Excellencecluster Cardio-Pulmonary System (ECCPS), German Lung Center (DZL), Universities of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig-University Giessen , Giessen, Germany
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12
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Signaling mechanisms and functional roles of cofilin phosphorylation and dephosphorylation. Cell Signal 2012; 25:457-69. [PMID: 23153585 DOI: 10.1016/j.cellsig.2012.11.001] [Citation(s) in RCA: 284] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 11/05/2012] [Indexed: 01/12/2023]
Abstract
Cofilin and actin-depolymerizing factor (ADF) are actin-binding proteins that play an essential role in regulating actin filament dynamics and reorganization by stimulating the severance and depolymerization of actin filaments. Cofilin/ADF are inactivated by phosphorylation at the serine residue at position 3 by LIM-kinases (LIMKs) and testicular protein kinases (TESKs) and are reactivated by dephosphorylation by the slingshot (SSH) family of protein phosphatases and chronophin. This review describes recent advances in our understanding of the signaling mechanisms regulating LIMKs and SSHs and the functional roles of cofilin phospho-regulation in cell migration, tumor invasion, mitosis, neuronal development, and synaptic plasticity. Accumulating evidence demonstrates that the phospho-regulation of cofilin/ADF is a key convergence point of cell signaling networks that link extracellular stimuli to actin cytoskeletal dynamics and that spatiotemporal control of cofilin/ADF activity by LIMKs and SSHs plays a crucial role in a diverse array of cellular and physiological processes. Perturbations in the normal control of cofilin/ADF activity underlie many pathological conditions, including cancer metastasis and neurological and cardiovascular disorders.
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Torres RA, Drake DA, Solodushko V, Jadhav R, Smith E, Rocic P, Weber DS. Slingshot isoform-specific regulation of cofilin-mediated vascular smooth muscle cell migration and neointima formation. Arterioscler Thromb Vasc Biol 2012; 31:2424-31. [PMID: 21868701 DOI: 10.1161/atvbaha.111.232769] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We hypothesized that cofilin activation by members of the slingshot (SSH) phosphatase family is a key mechanism regulating vascular smooth muscle cell (VSMC) migration and neoinitima formation following vascular injury. METHODS AND RESULTS Scratch wound and modified Boyden chamber assays were used to assess VSMC migration following downregulation of the expression of cofilin and each SSH phosphatase isoform (SSH1, SSH2, and SSH3) by small interfering RNA (siRNA), respectively. Cofilin siRNA greatly attenuated the ability of VSMC migration into the "wound," and platelet-derived growth factor (PDGF)-induced migration was virtually eliminated versus a 3.5-fold increase in nontreated VSMCs, establishing a critical role for cofilin in VSMC migration. Cofilin activation (dephosphorylation) was increased in PDGF-stimulated VSMCs. Thus, we assessed the role of the SSH family of phosphatases on cofilin activation and VSMC migration. Treatment with either SSH1 or SSH2 siRNA attenuated cofilin activation, whereas SSH3 siRNA had no effect. Only SSH1 siRNA significantly reduced wound healing and PDGF-induced VSMC migration. Both SSH1 expression (4.7-fold) and cofilin expression (3.9-fold) were increased in balloon injured versus noninjured carotid arteries, and expression was prevalent in the neointima. CONCLUSION These studies demonstrate that the regulation of VSMC migration by cofilin is SSH1 dependent and that this mechanism potentially contributes to neointima formation following vascular injury in vivo.
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Affiliation(s)
- Rebecca A Torres
- Department of Physiology, University of South Alabama, Mobile, AL, USA
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14
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Howarth JW, Ramisetti S, Nolan K, Sadayappan S, Rosevear PR. Structural insight into unique cardiac myosin-binding protein-C motif: a partially folded domain. J Biol Chem 2012; 287:8254-62. [PMID: 22235120 DOI: 10.1074/jbc.m111.309591] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The structural role of the unique myosin-binding motif (m-domain) of cardiac myosin-binding protein-C remains unclear. Functionally, the m-domain is thought to directly interact with myosin, whereas phosphorylation of the m-domain has been shown to modulate interactions between myosin and actin. Here we utilized NMR to analyze the structure and dynamics of the m-domain in solution. Our studies reveal that the m-domain is composed of two subdomains, a largely disordered N-terminal portion containing three known phosphorylation sites and a more ordered and folded C-terminal portion. Chemical shift analyses, d(NN)(i, i + 1) NOEs, and (15)N{(1)H} heteronuclear NOE values show that the C-terminal subdomain (residues 315-351) is structured with three well defined helices spanning residues 317-322, 327-335, and 341-348. The tertiary structure was calculated with CS-Rosetta using complete (13)C(α), (13)C(β), (13)C', (15)N, (1)H(α), and (1)H(N) chemical shifts. An ensemble of 20 acceptable structures was selected to represent the C-terminal subdomain that exhibits a novel three-helix bundle fold. The solvent-exposed face of the third helix was found to contain the basic actin-binding motif LK(R/K)XK. In contrast, (15)N{(1)H} heteronuclear NOE values for the N-terminal subdomain are consistent with a more conformationally flexible region. Secondary structure propensity scores indicate two transient helices spanning residues 265-268 and 293-295. The presence of both transient helices is supported by weak sequential d(NN)(i, i + 1) NOEs. Thus, the m-domain consists of an N-terminal subdomain that is flexible and largely disordered and a C-terminal subdomain having a three-helix bundle fold, potentially providing an actin-binding platform.
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Affiliation(s)
- Jack W Howarth
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA
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15
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Barišić S, Nagel AC, Franz-Wachtel M, Macek B, Preiss A, Link G, Maier D, Hausser A. Phosphorylation of Ser 402 impedes phosphatase activity of slingshot 1. EMBO Rep 2011; 12:527-33. [PMID: 21525957 DOI: 10.1038/embor.2011.53] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 03/21/2011] [Accepted: 03/22/2011] [Indexed: 11/09/2022] Open
Abstract
By using mass spectrometry, we have identified Ser 402 as a new phosphorylation site within the catalytic domain of human slingshot 1 (SSH1). Phosphorylation at this site inhibits substrate binding and, thus, phosphatase activity in vitro, resulting in enrichment of phosphorylated cofilin in monolayer cell culture. We further demonstrate that protein kinase D (PKD) is upstream from Ser 402 phosphorylation. Accordingly, expression of active PKD in Drosophila phenotypically mimics the loss of SSH activity by inducing accumulation of phosphorylated cofilin and filamentous actin. We thus identify a universal mechanism by which PKD controls SSH1 phosphatase activity.
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Affiliation(s)
- Sandra Barišić
- Institute for Cell Biology and Immunology, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
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16
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Molecular basis for the dual function of Eps8 on actin dynamics: bundling and capping. PLoS Biol 2010; 8:e1000387. [PMID: 20532239 PMCID: PMC2879411 DOI: 10.1371/journal.pbio.1000387] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 04/22/2010] [Indexed: 11/20/2022] Open
Abstract
Actin capping and cross-linking proteins regulate the dynamics and architectures of different cellular protrusions. Eps8 is the founding member of a unique family of capping proteins capable of side-binding and bundling actin filaments. However, the structural basis through which Eps8 exerts these functions remains elusive. Here, we combined biochemical, molecular, and genetic approaches with electron microscopy and image analysis to dissect the molecular mechanism responsible for the distinct activities of Eps8. We propose that bundling activity of Eps8 is mainly mediated by a compact four helix bundle, which is contacting three actin subunits along the filament. The capping activity is mainly mediated by a amphipathic helix that binds within the hydrophobic pocket at the barbed ends of actin blocking further addition of actin monomers. Single-point mutagenesis validated these modes of binding, permitting us to dissect Eps8 capping from bundling activity in vitro. We further showed that the capping and bundling activities of Eps8 can be fully dissected in vivo, demonstrating the physiological relevance of the identified Eps8 structural/functional modules. Eps8 controls actin-based motility through its capping activity, while, as a bundler, is essential for proper intestinal morphogenesis of developing Caenorhabditis elegans.
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Eiseler T, Hausser A, De Kimpe L, Van Lint J, Pfizenmaier K. Protein kinase D controls actin polymerization and cell motility through phosphorylation of cortactin. J Biol Chem 2010; 285:18672-83. [PMID: 20363754 DOI: 10.1074/jbc.m109.093880] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We here identify protein kinase D (PKD) as an upstream regulator of the F-actin-binding protein cortactin and the Arp actin polymerization machinery. PKD phosphorylates cortactin in vitro and in vivo at serine 298 thereby generating a 14-3-3 binding motif. In vitro, a phosphorylation-deficient cortactin-S298A protein accelerated VCA-Arp-cortactin-mediated synergistic actin polymerization and showed reduced F-actin binding, indicative of enhanced turnover of nucleation complexes. In vivo, cortactin co-localized with the nucleation promoting factor WAVE2, essential for lamellipodia extension, in the actin polymerization zone in Heregulin-treated MCF-7 cells. Using a 3-dye FRET-based approach we further demonstrate that WAVE2-Arp and cortactin prominently interact at these structures. Accordingly, cortactin-S298A significantly enhanced lamellipodia extension and directed cell migration. Our data thus unravel a previously unrecognized mechanism by which PKD controls cancer cell motility.
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Affiliation(s)
- Tim Eiseler
- Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart 70569, Germany
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18
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Brown DI, Griendling KK. Nox proteins in signal transduction. Free Radic Biol Med 2009; 47:1239-53. [PMID: 19628035 PMCID: PMC2763943 DOI: 10.1016/j.freeradbiomed.2009.07.023] [Citation(s) in RCA: 628] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 07/10/2009] [Accepted: 07/14/2009] [Indexed: 02/07/2023]
Abstract
The NADPH oxidase (Nox) family of superoxide (O(2)(*-)) and hydrogen peroxide (H(2)O(2))-producing proteins has emerged as an important source of reactive oxygen species (ROS) in signal transduction. ROS produced by Nox proteins Nox1-5 and Duox1/2 are now recognized to play essential roles in the physiology of the brain, the immune system, the vasculature, and the digestive tract as well as in hormone synthesis. Nox-derived ROS have been implicated in regulation of cytoskeletal remodeling, gene expression, proliferation, differentiation, migration, and cell death. These processes are tightly controlled and reversible. In this review, we will discuss recent literature on Nox protein tissue distribution, subcellular localization, activation, and the resulting signal transduction mechanisms.
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Affiliation(s)
- David I Brown
- Department of Medicine, Division of Cardiology, Emory University, 1639 Pierce Drive, 319 WMB Atlanta, GA 30322, USA
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Eiseler T, Döppler H, Yan IK, Kitatani K, Mizuno K, Storz P. Protein kinase D1 regulates cofilin-mediated F-actin reorganization and cell motility through slingshot. Nat Cell Biol 2009; 11:545-56. [PMID: 19329994 PMCID: PMC2761768 DOI: 10.1038/ncb1861] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Accepted: 02/19/2009] [Indexed: 01/27/2023]
Abstract
Dynamic actin remodelling processes at the leading edge of migrating tumour cells are concerted events controlled by a fine-tuned temporal and spatial interplay of kinases and phosphatases. Actin severing is regulated by ADF/Cofilin which regulates stimulus-induced lamellipodia protrusion and directed cell motility. Cofilin is activated by dephosphorylation via phosphatases of the slingshot (SSH) family. SSH activity is strongly increased by its binding to filamentous actin (F-actin), however, other upstream regulators remain unknown. We show that in response to RhoA activation, Protein Kinase D1 (PKD1) phosphorylates the SSH enzyme SSH1L at a serine residue located in its actin binding motif. This generates a 14-3-3 binding motif, blocks the localization of SSH1L to F-actin-rich structures in the lamellipodium by sequestering it in the cytoplasm. Consequently, expression of constitutively-active PKD1 in invasive tumour cells enhanced phosphorylation of cofilin and effectively blocked the formation of free actin filament barbed ends and directed cell migration.
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Affiliation(s)
- Tim Eiseler
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
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20
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Properties of an ezrin mutant defective in F-actin binding. J Mol Biol 2008; 385:1015-31. [PMID: 19084535 DOI: 10.1016/j.jmb.2008.11.051] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 11/01/2008] [Accepted: 11/10/2008] [Indexed: 11/21/2022]
Abstract
Ezrin, radixin and moesin are a family of proteins that provide a link between the plasma membrane and the cortical actin cytoskeleton. The regulated targeting of ezrin to the plasma membrane and its association with cortical F-actin are more than likely functions necessary for a number of cellular processes, such as cell adhesion, motility, morphogenesis and cell signalling. The interaction with F-actin was originally mapped to the last 34 residues of ezrin, which correspond to the last three helices (alphaB, alphaC and alphaD) of the C-terminal tail. We set out to identify and mutate the ezrin/F-actin binding site in order to pinpoint the role of F-actin interaction in morphological processes as well as signal transduction. We report here the generation of an ezrin mutant defective in F-actin binding. We identified four actin-binding residues, T576, K577, R579 and I580, that form a contiguous patch on the surface of the last helix, alphaD. Interestingly, mutagenesis of R579 also eliminated the interaction of band four-point one, ezrin, radixin, moesin homology domains (FERM) and the C-terminal tail domain, identifying a hotspot of the FERM/tail interaction. In vivo expression of the ezrin mutant defective in F-actin binding and FERM/tail interaction (R579A) altered the normal cell surface structure dramatically and inhibited cell migration. Further, we showed that ezrin/F-actin binding is required for the receptor tyrosine kinase signal transfer to the Ras/MAP kinase signalling pathway. Taken together, these observations highlight the importance of ezrin/F-actin function in the development of dynamic membrane/actin structures critical for cell shape and motility, as well as signal transduction.
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Kurita S, Watanabe Y, Gunji E, Ohashi K, Mizuno K. Molecular dissection of the mechanisms of substrate recognition and F-actin-mediated activation of cofilin-phosphatase Slingshot-1. J Biol Chem 2008; 283:32542-52. [PMID: 18809681 DOI: 10.1074/jbc.m804627200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Slingshot-1 (SSH1), a member of a dual-specificity protein phosphatase family, regulates actin dynamics by dephosphorylating and reactivating cofilin, an actin-depolymerizing factor. SSH1 has the SSH family-specific, N-terminal, noncatalytic (SSH-N) domain, consisting of the A and B subdomains. SSH1 is activated by binding to actin filaments. In this study, we examined the mechanisms of SSH1 substrate recognition of phospho-cofilin (P-cofilin) and SSH1 activation by F-actin. We found that P-cofilin binds to a phosphatase-inactive mutant, SSH1(CS), in which the catalytic Cys-393 is replaced by Ser. Using a series of deletion mutants, we provided evidence that both the phosphatase (P) domain and the adjacent B domain are indispensable for P-cofilin binding of SSH1(CS) and cofilin-phosphatase activity of SSH1. In contrast, the A domain is required for the F-actin-mediated activation of SSH1, but not for P-cofilin binding or basal cofilin-phosphatase activity. The P domain alone is sufficient for the phosphatase activity toward p-nitrophenyl phosphate (pNPP), indicating that the SSH-N domain is not essential for the basal phosphatase activity of SSH1. Addition of F-actin increased the cofilin-phosphatase activity of SSH1 more than 1200-fold, but the pNPP-phosphatase activity only 2.2-fold, which suggests that F-actin principally affects the cofilin-specific phosphatase activity of SSH1. When expressed in cultured cells, SSH1, but not its mutant deleted of SSH-N, accumulated in the rear of the lamellipodium. Together, these findings suggest that the conserved SSH-N domain plays critical roles in P-cofilin recognition, F-actin-mediated activation, and subcellular localization of SSH1.
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Affiliation(s)
- Souichi Kurita
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
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22
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Van Troys M, Huyck L, Leyman S, Dhaese S, Vandekerkhove J, Ampe C. Ins and outs of ADF/cofilin activity and regulation. Eur J Cell Biol 2008; 87:649-67. [PMID: 18499298 DOI: 10.1016/j.ejcb.2008.04.001] [Citation(s) in RCA: 253] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 03/25/2008] [Accepted: 04/02/2008] [Indexed: 12/15/2022] Open
Abstract
The actin-binding proteins of the actin-depolymerisation factor (ADF)/cofilin family were first described more than three decades ago, but research on these proteins still occupies a front role in the actin and cell migration field. Moreover, cofilin activity is implicated in the malignant, invasive properties of cancer cells. The effects of ADF/cofilins on actin dynamics are diverse and their regulation is complex. In stimulated cells, multiple signalling pathways can be initiated resulting in different activation/deactivation switches that control ADF/cofilin activity. The output of this entire regulatory system, in combination with spatial and temporal segregation of the activation mechanisms, underlies the contribution of ADF/cofilins to various cell migration/invasion phenotypes. In this framework, we describe current views on how ADF/cofilins function in migrating and invading cells.
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Gimona M. The microfilament system in the formation of invasive adhesions. Semin Cancer Biol 2008; 18:23-34. [DOI: 10.1016/j.semcancer.2007.08.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 08/30/2007] [Accepted: 08/31/2007] [Indexed: 12/23/2022]
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Kligys K, Claiborne JN, DeBiase PJ, Hopkinson SB, Wu Y, Mizuno K, Jones JCR. The slingshot family of phosphatases mediates Rac1 regulation of cofilin phosphorylation, laminin-332 organization, and motility behavior of keratinocytes. J Biol Chem 2007; 282:32520-8. [PMID: 17848544 PMCID: PMC2754063 DOI: 10.1074/jbc.m707041200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The motility of keratinocytes is an essential component of wound closure and the development of epidermal tumors. In vitro, the specific motile behavior of keratinocytes is dictated by the assembly of laminin-332 tracks, a process that is dependent upon alpha6beta4 integrin signaling to Rac1 and the actin-severing protein cofilin. Here we have analyzed how cofilin phosphorylation is regulated by phosphatases (slingshot (SSH) or chronophin (CIN)) downstream of signaling by alpha6beta4 integrin/Rac1 in human keratinocytes. Keratinocytes express all members of the SSH family (SSH1, SSH2, and SSH3) and CIN. However, expression of phosphatase-dead versions of all three SSH proteins, but not dominant inactive CIN, results in phosphorylation/inactivation of cofilin, changes in actin cytoskeleton organization, loss of cell polarity, and assembly of aberrant arrays of laminin-332 in human keratinocytes. SSH activity is regulated by 14-3-3 protein binding, and intriguingly, 14-3-3/alpha6beta4 integrin protein interaction is required for keratinocyte migration. We wondered whether 14-3-3 proteins function as regulators of Rac1-mediated keratinocyte migration patterns. In support of this hypothesis, inhibition of Rac1 results in an increase in 14-3-3 protein association with SSH. Thus, we propose a novel mechanism in which alpha6beta4 integrin signaling via Rac1, 14-3-3 proteins, and SSH family members regulates cofilin activation, cell polarity, and matrix assembly, leading to specific epidermal cell migration behavior.
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Affiliation(s)
- Kristina Kligys
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Jessica N. Claiborne
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Phillip J. DeBiase
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Susan B. Hopkinson
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Yvonne Wu
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Kensaku Mizuno
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Jonathan C. R. Jones
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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Kurita S, Gunji E, Ohashi K, Mizuno K. Actin filaments-stabilizing and -bundling activities of cofilin-phosphatase Slingshot-1. Genes Cells 2007; 12:663-76. [PMID: 17535256 DOI: 10.1111/j.1365-2443.2007.01078.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Slingshot-1 (SSH1) is known to regulate actin filament dynamics by dephosphorylating and activating cofilin, an actin-depolymerizing factor. SSH1 binds to filamentous (F-) actin through its multiple F-actin-binding sites and its cofilin-phosphatase activity is enhanced by binding to F-actin. In this study, we demonstrate that SSH1 has F-actin-stabilizing and -bundling activities. In vitro actin depolymerization assays revealed that SSH1 suppressed spontaneous and cofilin-induced actin depolymerization in a dose-dependent manner. SSH1 inhibited F-actin binding and severing activities of cofilin. Low-speed centrifugation assays combined with fluorescence and electron microscopic analysis revealed that SSH1 has F-actin-bundling activity, independently of its cofilin-phosphatase activity. Deletion of N- or C-terminal regions of SSH1 significantly reduced its F-actin-stabilizing and -bundling activities, indicating that both regions are critical for these functions. As SSH1 does not form a homodimer, it probably bundles F-actin through its multiple F-actin-binding sites. Knockdown of SSH1 expression by RNA interference significantly suppressed stress fiber formation in C2C12 myoblast cells, indicating a role for SSH1 in stress fiber formation or stabilization in cells. SSH1 thus has the potential to regulate actin filament dynamics and organization in cells via F-actin-stabilizing and -bundling activities, in addition to its ability to dephosphorylate cofilin.
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Affiliation(s)
- Souichi Kurita
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
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Jovceva E, Larsen MR, Waterfield MD, Baum B, Timms JF. Dynamic cofilin phosphorylation in the control of lamellipodial actin homeostasis. J Cell Sci 2007; 120:1888-97. [PMID: 17504806 DOI: 10.1242/jcs.004366] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
During animal cell chemotaxis, signalling at the plasma membrane induces actin polymerisation to drive forward cell movement. Since the cellular pool of actin is limited, efficient protrusion formation also requires the coordinated disassembly of pre-existing actin filaments. To search for proteins that can monitor filamentous and globular actin levels to maintain the balance of polymerisation and disassembly, we followed changes in the proteome induced by RNA interference (RNAi)-mediated alterations in actin signalling. This unbiased approach revealed an increase in the levels of an inactive, phosphorylated form of the actin-severing protein cofilin in cells unable to generate actin-based lamellipodia. Conversely, an increase in F-actin levels induced the dephosphorylation and activation of cofilin via activation of the Ssh phosphatase. Similarly, in the context of acute phosphoinositide 3-kinase (PI3K) signalling, dynamic changes in cofilin phosphorylation were found to depend on the Ssh phosphatase and on changes in lamellipodial F-actin. These results indicate that changes in the extent of cofilin phosphorylation are regulated by Ssh in response to changes in the levels and/or organisation of F-actin. Together with the recent finding that Ssh phosphatase activity is augmented by F-actin binding, these results identify Ssh-dependent regulation of phosphorylated cofilin levels as an important feedback control mechanism that maintains actin filament homeostasis during actin signalling.
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Affiliation(s)
- Eleonora Jovceva
- Ludwig Institute for Cancer Research, UCL Branch, London, W1W 7BS, UK
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27
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Ono S. Mechanism of depolymerization and severing of actin filaments and its significance in cytoskeletal dynamics. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 258:1-82. [PMID: 17338919 DOI: 10.1016/s0074-7696(07)58001-0] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The actin cytoskeleton is one of the major structural components of the cell. It often undergoes rapid reorganization and plays crucial roles in a number of dynamic cellular processes, including cell migration, cytokinesis, membrane trafficking, and morphogenesis. Actin monomers are polymerized into filaments under physiological conditions, but spontaneous depolymerization is too slow to maintain the fast actin filament dynamics observed in vivo. Gelsolin, actin-depolymerizing factor (ADF)/cofilin, and several other actin-severing/depolymerizing proteins can enhance disassembly of actin filaments and promote reorganization of the actin cytoskeleton. This review presents advances as well as a historical overview of studies on the biochemical activities and cellular functions of actin-severing/depolymerizing proteins.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, GA 30322, USA
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