51
|
Alieva NO, Efremov AK, Hu S, Oh D, Chen Z, Natarajan M, Ong HT, Jégou A, Romet-Lemonne G, Groves JT, Sheetz MP, Yan J, Bershadsky AD. Myosin IIA and formin dependent mechanosensitivity of filopodia adhesion. Nat Commun 2019; 10:3593. [PMID: 31399564 PMCID: PMC6689027 DOI: 10.1038/s41467-019-10964-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 06/07/2019] [Indexed: 12/21/2022] Open
Abstract
Filopodia, dynamic membrane protrusions driven by polymerization of an actin filament core, can adhere to the extracellular matrix and experience both external and cell-generated pulling forces. The role of such forces in filopodia adhesion is however insufficiently understood. Here, we study filopodia induced by overexpression of myosin X, typical for cancer cells. The lifetime of such filopodia positively correlates with the presence of myosin IIA filaments at the filopodia bases. Application of pulling forces to the filopodia tips through attached fibronectin-coated laser-trapped beads results in sustained growth of the filopodia. Pharmacological inhibition or knockdown of myosin IIA abolishes the filopodia adhesion to the beads. Formin inhibitor SMIFH2, which causes detachment of actin filaments from formin molecules, produces similar effect. Thus, centripetal force generated by myosin IIA filaments at the base of filopodium and transmitted to the tip through actin core in a formin-dependent fashion is required for filopodia adhesion.
Collapse
Affiliation(s)
- N O Alieva
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - A K Efremov
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Center for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117557, Singapore
| | - S Hu
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - D Oh
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Z Chen
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - M Natarajan
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - H T Ong
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - A Jégou
- Institut Jacques Monod, CNRS, Université de Paris, 15 rue Helene Brion, F-75013, Paris, France
| | - G Romet-Lemonne
- Institut Jacques Monod, CNRS, Université de Paris, 15 rue Helene Brion, F-75013, Paris, France
| | - J T Groves
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - M P Sheetz
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
| | - J Yan
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Center for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117557, Singapore.,Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - A D Bershadsky
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore. .,Weizmann Institute of Science, Herzl St 234, Rehovot, 7610001, Israel.
| |
Collapse
|
52
|
A chemotaxis model to explain WHIM neutrophil accumulation in the bone marrow of WHIM mouse model. BLOOD SCIENCE 2019; 1:102-112. [PMID: 35402788 PMCID: PMC8975054 DOI: 10.1097/bs9.0000000000000019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/17/2019] [Indexed: 11/25/2022] Open
Abstract
Neutrophils are essential immune cells that defend the host against pathogenic microbial agents. Neutrophils are produced in the bone marrow and are retained there through CXCR4–CXCL12 signaling. However, patients with the Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) syndrome are prone to infections due to increased accumulation of neutrophils in the bone marrow leading to low numbers of circulating neutrophils. How neutrophils accumulate in the bone marrow in this condition is poorly understood. To better understand factors involved in neutrophil accumulation in the bone marrow, neutrophils from wildtype and WHIM mouse models were characterized in their response to CXCL12 stimulation. WHIM neutrophils were found to exert stronger traction forces, formed significantly more lamellipodia-type protrusions and migrated with increased speed and displacement upon CXCL12 stimulation as compared to wildtype cells. Migration speed of WHIM neutrophils showed a larger initial increase upon CXCL12 stimulation, which decayed over a longer time period as compared to wildtype cells. We proposed a computational model based on the chemotactic behavior of neutrophils that indicated increased CXCL12 sensitivity and prolonged CXCR4 internalization adaptation time in WHIM neutrophils as being responsible for increased accumulation in the bone marrow. These findings provide a mechanistic understanding of bone marrow neutrophil accumulation in WHIM condition and novel insights into restoring neutrophil regulation in WHIM patients.
Collapse
|
53
|
Tsygankova OM, Keen JH. A unique role for clathrin light chain A in cell spreading and migration. J Cell Sci 2019; 132:jcs.224030. [PMID: 30975920 DOI: 10.1242/jcs.224030] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 04/01/2019] [Indexed: 12/12/2022] Open
Abstract
Clathrin heavy chain is the structural component of the clathrin triskelion, but unique functions for the two distinct and highly conserved clathrin light chains (CLCa and CLCb, also known as CLTA and CLTB, respectively) have been elusive. Here, we show that following detachment and replating, CLCa is uniquely responsible for promoting efficient cell spreading and migration. Selective depletion of CLCa, but not of CLCb, reduced the initial phase of isotropic spreading of HeLa, H1299 and HEK293 cells by 60-80% compared to siRNA controls, and wound closure and motility by ∼50%. Surface levels of β1-integrins were unaffected by CLCa depletion. However, CLCa was required for effective targeting of FAK (also known as PTK2) and paxillin to the adherent surface of spreading cells, for integrin-mediated activation of Src, FAK and paxillin, and for maturation of focal adhesions, but not their microtubule-based turnover. Depletion of CLCa also blocked the interaction of clathrin with the nucleation-promoting factor WAVE complex, and altered actin distribution. Furthermore, preferential recruitment of CLCa to budding protrusions was also observed. These results comprise the first identification of CLCa-specific functions, with implications for normal and neoplastic integrin-based signaling and cell migration.
Collapse
Affiliation(s)
- Oxana M Tsygankova
- Department of Biochemistry and Molecular Biology, Cell Biology and Signaling Program of the Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - James H Keen
- Department of Biochemistry and Molecular Biology, Cell Biology and Signaling Program of the Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| |
Collapse
|
54
|
Ultrastructure and dynamics of the actin-myosin II cytoskeleton during mitochondrial fission. Nat Cell Biol 2019; 21:603-613. [PMID: 30988424 PMCID: PMC6499663 DOI: 10.1038/s41556-019-0313-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 03/14/2019] [Indexed: 02/05/2023]
Abstract
Mitochondrial fission involves the preconstriction of an organelle followed by scission by dynamin-related protein Drp1. Preconstriction is facilitated by actin and non-muscle myosin II through a mechanism that remains unclear, largely due to the unknown cytoskeletal ultrastructure at mitochondrial constrictions. Here, using platinum replica electron microscopy, we show that mitochondria in cells are embedded in an interstitial cytoskeletal network that contains abundant unbranched actin filaments. Both spontaneous and induced mitochondrial constrictions typically associate with a criss-cross array of long actin filaments that comprise part of this interstitial network. Non-muscle myosin II is found adjacent to mitochondria but is not specifically enriched at the constriction sites. During ionomycin-induced mitochondrial fission, F-actin clouds colocalize with mitochondrial constriction sites, whereas dynamic myosin II clouds are present in the vicinity of constrictions. We propose that myosin II promotes mitochondrial constriction by inducing stochastic deformations of the interstitial actin network, which applies pressure on the mitochondrial surface and thus initiates curvature-sensing mechanisms that complete mitochondrial constriction.
Collapse
|
55
|
Li M, Bing S, Qian Z. [Influence of dexamethasone on the cell polarity and PAR complex of the embryonic epithelial cells in the palate]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2019; 36:9-16. [PMID: 29594989 DOI: 10.7518/hxkq.2018.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study aims to investigate whether dexamethasone (DEX) can down-regulate the PAR complex and disrupt the cell polarity in the palatal epithelium during palatal fusion. METHODS Pregnant rats were randomly divided into control and DEX groups, which were injected intraperitoneally with 0.9% sodium chloride (0.1 mL) and DEX (6 mg·kg ⁻¹), respectively, every day from E10 to E12. The palatal epithelial morphology was observed using hematoxylin and eosin staining and scanning electron microscopy. Immunofluorescence staining, Western Blot analysis, and real-time polymerase chain reaction were performed to detect the expression of PAR3, PAR6, and aPKC. RESULTS The incidence of cleft palate in DEX group (46.15%) was significantly higher than that in control group (3.92%), and the difference was statistically significant (χ2=24.335, P=0.00). DEX can also retard the growth of the palatal shelves and the short palatal shelves. The morphology and arrangement of MEE cells changed from polarized bilayer cells to nonpolarized monolayer ones. Additionally, the spherical structure decreased, which caused the cleft palate. PAR3 and PAR6 were only detected in the palatal epithelium, and aPKC was expressed in the palatal epithelium and mesenchyme. DEX can reduce the expression levels of PAR3, PAR6, and aPKC in the protein and gene levels. CONCLUSIONS DEX can down-regulate the complex gene expression in the MEE cells, thereby destroying the cell polarity and causing cleft palate.
Collapse
Affiliation(s)
- Ma Li
- Dept. of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China;State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Shi Bing
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Zheng Qian
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| |
Collapse
|
56
|
Jacquemet G, Stubb A, Saup R, Miihkinen M, Kremneva E, Hamidi H, Ivaska J. Filopodome Mapping Identifies p130Cas as a Mechanosensitive Regulator of Filopodia Stability. Curr Biol 2019; 29:202-216.e7. [PMID: 30639111 PMCID: PMC6345628 DOI: 10.1016/j.cub.2018.11.053] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/25/2018] [Accepted: 11/20/2018] [Indexed: 01/09/2023]
Abstract
Filopodia are adhesive cellular protrusions specialized in the detection of extracellular matrix (ECM)-derived cues. Although ECM engagement at focal adhesions is known to trigger the recruitment of hundreds of proteins ("adhesome") to fine-tune cellular behavior, the components of the filopodia adhesions remain undefined. Here, we performed a structured-illumination-microscopy-based screen to map the localization of 80 target proteins, linked to cell adhesion and migration, within myosin-X-induced filopodia. We demonstrate preferential enrichment of several adhesion proteins to either filopodia tips, filopodia shafts, or shaft subdomains, suggesting divergent, spatially restricted functions for these proteins. Moreover, proteins with phosphoinositide (PI) binding sites are particularly enriched in filopodia. This, together with the strong localization of PI(3,4)P2 in filopodia tips, predicts critical roles for PIs in regulating filopodia ultra-structure and function. Our mapping further reveals that filopodia adhesions consist of a unique set of proteins, the filopodome, that are distinct from classical nascent adhesions, focal adhesions, and fibrillar adhesions. Using live imaging, we observe that filopodia adhesions can give rise to nascent adhesions, which, in turn, form focal adhesions. We demonstrate that p130Cas (BCAR1) is recruited to filopodia tips via its C-terminal Cas family homology domain (CCHD) and acts as a mechanosensitive regulator of filopodia stability. Finally, we demonstrate that our map based on myosin-X-induced filopodia can be translated to endogenous filopodia and fascin- and IRSp53-mediated filopodia.
Collapse
Affiliation(s)
- Guillaume Jacquemet
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland.
| | - Aki Stubb
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Rafael Saup
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Mitro Miihkinen
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Elena Kremneva
- Institute of Biotechnology, University of Helsinki, PO Box 56, 00014 Helsinki, Finland
| | - Hellyeh Hamidi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Johanna Ivaska
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland; Department of Biochemistry, University of Turku, Turku, Finland.
| |
Collapse
|
57
|
Abstract
Formin homology proteins (formins) are a highly conserved family of cytoskeletal remodeling proteins that are involved in a diverse array of cellular functions. Formins are best known for their ability to regulate actin dynamics, but the same functional domains also govern stability and organization of microtubules. It is thought that this dual activity allows them to coordinate the activity of these two major cytoskeletal networks and thereby influence cellular architecture. Golgi ribbon assembly is dependent upon cooperative interactions between actin filaments and cytoplasmic microtubules originating both at the Golgi itself and from the centrosome. Similarly, centrosome assembly, centriole duplication, and centrosome positioning are also reliant on a dialogue between both cytoskeletal networks. As presented in this chapter, a growing body of evidence suggests that multiple formin proteins play essential roles in these central cellular processes.
Collapse
Affiliation(s)
- John Copeland
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
| |
Collapse
|
58
|
Velle KB, Campellone KG. Enteropathogenic E. coli relies on collaboration between the formin mDia1 and the Arp2/3 complex for actin pedestal biogenesis and maintenance. PLoS Pathog 2018; 14:e1007485. [PMID: 30550556 PMCID: PMC6310289 DOI: 10.1371/journal.ppat.1007485] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 12/28/2018] [Accepted: 11/23/2018] [Indexed: 12/16/2022] Open
Abstract
Enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC) are closely related extracellular pathogens that reorganize host cell actin into “pedestals” beneath the tightly adherent bacteria. This pedestal-forming activity is both a critical step in pathogenesis, and it makes EPEC and EHEC useful models for studying the actin rearrangements that underlie membrane protrusions. To generate pedestals, EPEC relies on the tyrosine phosphorylated bacterial effector protein Tir to bind host adaptor proteins that recruit N-WASP, a nucleation-promoting factor that activates the Arp2/3 complex to drive actin polymerization. In contrast, EHEC depends on the effector EspFU to multimerize N-WASP and promote Arp2/3 activation. Although these core pathways of pedestal assembly are well-characterized, the contributions of additional actin nucleation factors are unknown. We investigated potential cooperation between the Arp2/3 complex and other classes of nucleators using chemical inhibitors, siRNAs, and knockout cell lines. We found that inhibition of formins impairs actin pedestal assembly, motility, and cellular colonization for bacteria using the EPEC, but not the EHEC, pathway of actin polymerization. We also identified mDia1 as the formin contributing to EPEC pedestal assembly, as its expression level positively correlates with the efficiency of pedestal formation, and it localizes to the base of pedestals both during their initiation and once they have reached steady state. Collectively, our data suggest that mDia1 enhances EPEC pedestal biogenesis and maintenance by generating seed filaments to be used by the N-WASP-Arp2/3-dependent actin nucleation machinery and by sustaining Src-mediated phosphorylation of Tir. Microbial pathogens that rearrange the host actin cytoskeleton have made valuable contributions to our understanding of cell signaling and movement. The assembly and organization of the actin cytoskeleton is driven by proteins called nucleators, which can be manipulated by bacteria including enteropathogenic Escherichia coli (EPEC), a frequent cause of pediatric diarrhea in developing countries. After ingestion, EPEC adhere tightly to cells of the intestine and hijack the underlying cytoskeleton to create protrusions called actin pedestals. While mechanisms of pedestal assembly involving a nucleator called the Arp2/3 complex have been defined for EPEC, the contribution of additional host nucleators has not been determined. We assessed the roles of several actin nucleators in EPEC pedestals and found that in addition to Arp2/3 complex-mediated nucleation, the formin mDia1 is a key contributor to actin assembly. These findings highlight the importance of nucleator collaboration in pathogenesis, and also advance our understanding of the molecular and cellular basis of EPEC infection, which is ultimately important for the discovery of new drug targets.
Collapse
Affiliation(s)
- Katrina B. Velle
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, United States of America
| | - Kenneth G. Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail:
| |
Collapse
|
59
|
Young LE, Latario CJ, Higgs HN. Roles for Ena/VASP proteins in FMNL3-mediated filopodial assembly. J Cell Sci 2018; 131:131/21/jcs220814. [PMID: 30373894 DOI: 10.1242/jcs.220814] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 09/25/2018] [Indexed: 02/01/2023] Open
Abstract
Filopodia are actin-dependent finger-like structures that protrude from the plasma membrane. Actin filament barbed-end-binding proteins localized to filopodial tips are key to filopodial assembly. Two classes of barbed-end-binding proteins are formins and Ena/VASP proteins, and both classes have been localized to filopodial tips in specific cellular contexts. Here, we examine the filopodial roles of the FMNL formins and Ena/VASP proteins in U2OS cells. FMNL3 suppression reduces filopodial assembly by 90%, and FMNL3 is enriched at >95% of filopodial tips. Suppression of VASP or Mena (also known as ENAH) reduces filopodial assembly by >75%. However, VASP and Mena do not display consistent filopodial tip localization, but are enriched in focal adhesions (FAs). Interestingly, >85% of FMNL3-containing filopodia are associated with FAs. Two situations increase Ena/VASP filopodial localization: (1) expression of myosin-X, and (2) actively spreading cells. In spreading cells, filopodia often mark sites of nascent adhesions. Interestingly, VASP suppression in spreading cells causes a significant increase in adhesion assembly at filopodial tips. This work demonstrates that, in U2OS cells, Ena/VASP proteins play roles in filopodia beyond those at filopodial tips.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Lorna E Young
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Casey J Latario
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Henry N Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| |
Collapse
|
60
|
Zeng YF, Xiao YS, Liu Y, Luo XJ, Wen LD, Liu Q, Chen M. Formin-like 3 regulates RhoC/FAK pathway and actin assembly to promote cell invasion in colorectal carcinoma. World J Gastroenterol 2018; 24:3884-3897. [PMID: 30228782 PMCID: PMC6141330 DOI: 10.3748/wjg.v24.i34.3884] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 06/16/2018] [Accepted: 06/27/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To clarify the underlying mechanism of formin-like 3 (FMNL3) in the promotion of colorectal carcinoma (CRC) cell invasion.
METHODS The in vitro biological function analyses of FMNL3 were performed by gain- and loss-of function approaches. Changes in the F-actin cytoskeleton were detected by the technologies of phalloidin-TRITC labeling and confocal microscopy. The signaling pathway mediated by FMNL3 was explored by western blot, gelatin zymograph assay, co-immunoprecipitation (co-IP), immunofluorescence co-localization, and glutathione S-transferase (GST) pull-down assay.
RESULTS The in vitro experimental results showed that FMNL3 significantly promoted the proliferation, invasion, and migration of CRC cells (P < 0.05 and P < 0.01). Moreover, FMNL3 regulated the remodeling of actin-based protrusions such as filopodia and lamellipodia in a RhoC-dependent manner. The western blot and gelatin zymograph assay results indicated that FMNL3 was involved in the RhoC/ focal adhesion kinase (FAK) pathway and acted as an effector of RhoC to activate the downstream signaling of p-FAK as well as p-MAPK and p-AKT. This resulted in the increased expression of matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9) and vascular endothelial growth factor (VEGF), and the subsequent promotion of CRC cell invasion. The results of TAE226, U0126 or Ly294002 treatment confirmed an essential role of FMNL3 in activation of the RhoC/FAK pathway and the subsequent promotion of CRC invasion. Co-IP, co-localization and GST pull-down assays showed the direct interaction of FMNL3 with RhoC in vivo and in vitro.
CONCLUSION FMNL3 regulates the RhoC/FAK signaling pathway and RhoC-dependent remodeling of actin-based protrusions to promote CRC invasion.
Collapse
Affiliation(s)
- Yuan-Feng Zeng
- Department of Pathology, Jiangxi Provincial People’s Hospital, Nanchang 330006, Jiangxi Province, China
| | - Yi-Sheng Xiao
- Teaching and Researching Section of Morphology, College of Basic Medicine, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, Jiangxi Province, China
| | - Yong Liu
- Department of Pathology, Jiangxi Provincial People’s Hospital, Nanchang 330006, Jiangxi Province, China
| | - Xiao-Jiang Luo
- Department of General Surgery, Jiangxi Provincial People’s Hospital, Nanchang 330006, Jiangxi Province, China
| | - Li-Dan Wen
- Clinical Medical Sciences Institute, Jiangxi Provincial People’s Hospital, Nanchang 330006, Jiangxi Province, China
| | - Qian Liu
- Department of Pathology, Jiangxi Provincial People’s Hospital, Nanchang 330006, Jiangxi Province, China
| | - Min Chen
- Department of Pathology, Jiangxi Provincial People’s Hospital, Nanchang 330006, Jiangxi Province, China
| |
Collapse
|
61
|
Profiling cellular morphodynamics by spatiotemporal spectrum decomposition. PLoS Comput Biol 2018; 14:e1006321. [PMID: 30071020 PMCID: PMC6091976 DOI: 10.1371/journal.pcbi.1006321] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 08/14/2018] [Accepted: 06/22/2018] [Indexed: 12/12/2022] Open
Abstract
Cellular morphology and associated morphodynamics are widely used for qualitative and quantitative assessments of cell state. Here we implement a framework to profile cellular morphodynamics based on an adaptive decomposition of local cell boundary motion into instantaneous frequency spectra defined by the Hilbert-Huang transform (HHT). Our approach revealed that spontaneously migrating cells with approximately homogeneous molecular makeup show remarkably consistent instantaneous frequency distributions, though they have markedly heterogeneous mobility. Distinctions in cell edge motion between these cells are captured predominantly by differences in the magnitude of the frequencies. We found that acute photo-inhibition of Vav2 guanine exchange factor, an activator of the Rho family of signaling proteins coordinating cell motility, produces significant shifts in the frequency distribution, but does not affect frequency magnitude. We therefore concluded that the frequency spectrum encodes the wiring of the molecular circuitry that regulates cell boundary movements, whereas the magnitude captures the activation level of the circuitry. We also used HHT spectra as multi-scale spatiotemporal features in statistical region merging to identify subcellular regions of distinct motion behavior. In line with our conclusion that different HHT spectra relate to different signaling regimes, we found that subcellular regions with different morphodynamics indeed exhibit distinct Rac1 activities. This algorithm thus can serve as an accurate and sensitive classifier of cellular morphodynamics to pinpoint spatial and temporal boundaries between signaling regimes. Many studies in cell biology employ global shape descriptors to probe mechanisms of cell morphogenesis. Here, we implement a framework in this paper to profile cellular morphodynamics very locally. We employ the Hilbert-Huang transform (HHT) to extract along the entire cell edge spectra of instantaneous edge motion frequency and magnitude and use them to classify overall cell behavior as well as subcellular edge sectors of distinct dynamics. We find in fibroblast-like COS7 cells that the marked heterogeneity in mobility of an unstimulated population is fully captured by differences in the magnitude spectra, while the frequency spectra are conserved between cells. Using optogenetics to acutely inhibit morphogenetic signaling pathways we find that these molecular shifts are reflected by changes in the frequency spectra but not in the magnitude spectra. After clustering cell edge sectors with distinct morphodynamics we observe in cells expressing a Rac1 activity biosensor that the sectors with different frequency spectra associate with different signaling intensity and dynamics. Together, these observations let us conclude that the frequency spectrum encodes the wiring of the molecular circuitry that regulates edge movements, whereas the magnitude captures the activation level of the circuitry.
Collapse
|
62
|
Yasuda-Yamahara M, Rogg M, Yamahara K, Maier JI, Huber TB, Schell C. AIF1L regulates actomyosin contractility and filopodial extensions in human podocytes. PLoS One 2018; 13:e0200487. [PMID: 30001384 PMCID: PMC6042786 DOI: 10.1371/journal.pone.0200487] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/27/2018] [Indexed: 11/17/2022] Open
Abstract
Podocytes are highly-specialized epithelial cells essentially required for the generation and the maintenance of the kidney filtration barrier. This elementary function is directly based on an elaborated cytoskeletal apparatus establishing a complex network of primary and secondary processes. Here, we identify the actin-bundling protein allograft-inflammatory-inhibitor 1 like (AIF1L) as a selectively expressed podocyte protein in vivo. We describe the distinct subcellular localization of AIF1L to actin stress fibers, focal adhesion complexes and the nuclear compartment of podocytes in vitro. Genetic deletion of AIF1L in immortalized human podocytes resulted in an increased formation of filopodial extensions and decreased actomyosin contractility. By the use of SILAC based quantitative proteomics analysis we describe the podocyte specific AIF1L interactome and identify several components of the actomyosin machinery such as MYL9 and UNC45A as potential AIF1L interaction partners. Together, these findings indicate an involvement of AIF1L in the stabilization of podocyte morphology by titrating actomyosin contractility and membrane dynamics.
Collapse
Affiliation(s)
- Mako Yasuda-Yamahara
- Department of Medicine IV, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Manuel Rogg
- Department of Medicine IV, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Kosuke Yamahara
- Department of Medicine IV, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Jasmin I. Maier
- Department of Medicine IV, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute for Surgical Pathology, University Medical Center Freiburg, Freiburg, Germany
| | - Tobias B. Huber
- Department of Medicine IV, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- BIOSS Center for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Department of Medicine III, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
| | - Christoph Schell
- Department of Medicine IV, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute for Surgical Pathology, University Medical Center Freiburg, Freiburg, Germany
- Berta-Ottenstein Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| |
Collapse
|
63
|
Graubner FR, Gram A, Kautz E, Bauersachs S, Aslan S, Agaoglu AR, Boos A, Kowalewski MP. Uterine responses to early pre-attachment embryos in the domestic dog and comparisons with other domestic animal species. Biol Reprod 2018. [PMID: 28651344 PMCID: PMC5803782 DOI: 10.1093/biolre/iox063] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In the dog, there is no luteolysis in the absence of pregnancy. Thus, this species lacks any anti-luteolytic endocrine signal as found in other species that modulate uterine function during the critical period of pregnancy establishment. Nevertheless, in the dog an embryo-maternal communication must occur in order to prevent rejection of embryos. Based on this hypothesis, we performed microarray analysis of canine uterine samples collected during pre-attachment phase (days 10-12) and in corresponding non-pregnant controls, in order to elucidate the embryo attachment signal. An additional goal was to identify differences in uterine responses to pre-attachment embryos between dogs and other mammalian species exhibiting different reproductive patterns with regard to luteolysis, implantation, and preparation for placentation. Therefore, the canine microarray data were compared with gene sets from pigs, cattle, horses, and humans. We found 412 genes differentially regulated between the two experimental groups. The functional terms most strongly enriched in response to pre-attachment embryos related to extracellular matrix function and remodeling, and to immune and inflammatory responses. Several candidate genes were validated by semi-quantitative PCR. When compared with other species, best matches were found with human and equine counterparts. Especially for the pig, the majority of overlapping genes showed opposite expression patterns. Interestingly, 1926 genes did not pair with any of the other gene sets. Using a microarray approach, we report the uterine changes in the dog driven by the presence of embryos and compare these results with datasets from other mammalian species, finding common-, contrary-, and exclusively canine-regulated genes.
Collapse
Affiliation(s)
- Felix R Graubner
- Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Aykut Gram
- Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Ewa Kautz
- Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Stefan Bauersachs
- Institute of Agricultural Sciences, Animal Physiology, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Selim Aslan
- Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Near East University, Nicosia, North Cyprus
| | - Ali R Agaoglu
- Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Mehmet Akif Ersoy University, Burdur, Turkey
| | - Alois Boos
- Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Mariusz P Kowalewski
- Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| |
Collapse
|
64
|
Innocenti M. New insights into the formation and the function of lamellipodia and ruffles in mesenchymal cell migration. Cell Adh Migr 2018. [PMID: 29513145 DOI: 10.1080/19336918.2018.1448352] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lamellipodia and ruffles are veil-shaped cell protrusions composed of a highly branched actin filament meshwork assembled by the Arp2/3 complex. These structures not only hallmark the leading edge of cells adopting the adhesion-based mesenchymal mode of migration but are also thought to drive cell movement. Although regarded as textbook knowledge, the mechanism of formation of lamellipodia and ruffles has been revisited in the last years leveraging new technologies. Furthermore, recent observations have also challenged our current view of the function of lamellipodia and ruffles in mesenchymal cell migration. Here, I review this literature and compare it with older studies to highlight the controversies and the outstanding open issues in the field. Moreover, I outline simple and plausible explanations to reconcile conflicting results and conclusions. Finally, I integrate the mechanisms regulating actin-based protrusion in a unifying model that accounts for random and ballistic mesenchymal cell migration.
Collapse
Affiliation(s)
- Metello Innocenti
- a Division of Molecular Genetics, The Netherlands Cancer Institute , Plesmanlaan 121, Amsterdam , CX , The Netherlands
| |
Collapse
|
65
|
Zhang Z, Luo Z, Min W, Zhang L, Wu Y, Hu X. An anti-cancer WxxxE-containing azurin polypeptide inhibits Rac1-dependent STAT3 and ERK/GSK-3β signaling in breast cancer cells. Oncotarget 2018; 8:43091-43103. [PMID: 28549350 PMCID: PMC5522130 DOI: 10.18632/oncotarget.17759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/28/2017] [Indexed: 12/15/2022] Open
Abstract
In our previous study, we characterized a mycoplasmal small GTPase-like polypeptide of 240 amino acids that possesses an N-terminal WVLGE sequence. The N-terminal WVLGE sequence promotes activation of Rac1 and subsequent host cancer cell proliferation. To investigate the function of the WxxxE motif in the interaction with Rac1 and host tumor progression, we synthesized a 35-amino acid WVLGE-containing polypeptide derived from a cell-penetrating peptide derived from the azurin protein. We verified that the WVLGE-containing polypeptide targeted MCF-7 cells rather than MCF-10A cells. However, the WVLGE-containing polypeptide inhibited activation of Rac1 and induced cellular phenotypes that resulted from inhibition of Rac1. In addition, the WVLGE-containing polypeptide down-regulated phosphorylation of the STAT3 and ERK/GSK-3β signaling pathways, and this effect was abolished by either stimulation or inhibition of Rac1 activity. We also found that the WVLGE-containing polypeptide has a Rac1-dependent potential to suppress breast cancer growth in vitro and in vivo. We suggest that by acting as a Rac1 inhibitor, this novel polypeptide may be useful for the treatment of breast cancer.
Collapse
Affiliation(s)
- Zhe Zhang
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Zhiyong Luo
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Wenpu Min
- The First People's Hospital of Jingzhou, Jingzhou, People's Republic of China
| | - Lin Zhang
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yaqun Wu
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Xiaopeng Hu
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| |
Collapse
|
66
|
LeCorgne H, Tudosie AM, Lavik K, Su R, Becker KN, Moore S, Walia Y, Wisner A, Koehler D, Alberts AS, Williams FE, Eisenmann KM. Differential Toxicity of mDia Formin-Directed Functional Agonists and Antagonists in Developing Zebrafish. Front Pharmacol 2018; 9:340. [PMID: 29692731 PMCID: PMC5902741 DOI: 10.3389/fphar.2018.00340] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/23/2018] [Indexed: 12/16/2022] Open
Abstract
The mammalian Diaphanous-related (mDia) formins are cytoskeletal regulators that assemble and, in some cases, bundle filamentous actin (F-actin), as well as stabilize microtubules. The development of small molecule antagonists and agonists that interrogate mDia formin function has allowed us to investigate the roles of formins in disease states. A small molecule inhibitor of FH2 domain (SMIFH2) inhibits mDia-dependent actin dynamics and abrogates tumor cell migration and cell division in vitro and ex vivo tissue explants. mDia formin activation with small molecule intramimics IMM01/02 and mDia2-DAD peptides inhibited glioblastoma motility and invasion in vitro and ex vivo rat brain slices. However, SMIFH2, IMMs, and mDia2 DAD efficacy in vivo remains largely unexplored and potential toxicity across a range of developmental phenotypes has not been thoroughly characterized. In this study, we performed an in vivo screen of early life-stage toxicity in Danio rerio zebrafish embryos 2 days post-fertilization (dpf) in response to SMIFH2, IMM01/02, and mDia2 DAD. SMIFH2 at concentrations ≥5–10 μM induced significant defects in developing zebrafish, including shorter body lengths, tail curvature and defective tail cellularity, craniofacial malformations, pericardial edema, absent and/or compromised vasculature function and flow, depressed heart rates and increased mortality. Conversely, IMM and mDia2 DAD peptides were minimally toxic at concentrations up to 10–20 and 50 μM, respectively. SMIFH2's therapeutic potential may therefore be limited by its substantial in vivo toxicity at functional concentrations. mDia formin agonism with IMMs and mDia2 DADs may therefore be a more effective and less toxic anti-invasive therapeutic approach.
Collapse
Affiliation(s)
- Hunter LeCorgne
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| | - Andrew M Tudosie
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| | - Kari Lavik
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| | - Robin Su
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| | - Kathryn N Becker
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| | - Sara Moore
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| | - Yashna Walia
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| | - Alexander Wisner
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Health Science, Toledo, OH, United States
| | - Daniel Koehler
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Health Science, Toledo, OH, United States
| | - Arthur S Alberts
- Laboratory of Cell Structure and Signal Integration, Van Andel Research Institute, Grand Rapids, MI, United States
| | - Frederick E Williams
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Health Science, Toledo, OH, United States
| | - Kathryn M Eisenmann
- Department of Cancer Biology, University of Toledo Health Science, Toledo, OH, United States
| |
Collapse
|
67
|
TAGLN2 polymerizes G-actin in a low ionic state but blocks Arp2/3-nucleated actin branching in physiological conditions. Sci Rep 2018; 8:5503. [PMID: 29615809 PMCID: PMC5883021 DOI: 10.1038/s41598-018-23816-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/20/2018] [Indexed: 11/12/2022] Open
Abstract
TAGLN is an actin-binding protein family that comprises three isoforms with theorized roles in smooth muscle differentiation, tumour development, lymphocyte activation, and brain chemistry. However, their fundamental characteristics in regulation of the actin-based cytoskeleton are not fully understood. Here we show that TAGLN2 (including TAGLN1 and TAGLN3) extensively nucleates G-actin polymerization under low-salt conditions, where polymerization would be completely suppressed. The calponin homology domain and actin-binding loop are essential to mechanically connect two adjacent G-actins, thereby mediating multimeric interactions. However, TAGLN2 blocked the Arp2/3 complex binding to actin filaments under physiological salt conditions, thereby inhibiting branched actin nucleation. In HeLa and T cells, TAGLN2 enhanced filopodium-like membrane protrusion. Collectively, the dual functional nature of TAGLN2—G-actin polymerization and Arp2/3 complex inhibition—may account for the mechanisms of filopodia development at the edge of Arp2/3-rich lamellipodia in various cell types.
Collapse
|
68
|
Cortactin recruits FMNL2 to promote actin polymerization and endosome motility in invadopodia formation. Cancer Lett 2018; 419:245-256. [DOI: 10.1016/j.canlet.2018.01.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/23/2017] [Accepted: 01/08/2018] [Indexed: 01/28/2023]
|
69
|
Svitkina TM. Ultrastructure of the actin cytoskeleton. Curr Opin Cell Biol 2018; 54:1-8. [PMID: 29477121 DOI: 10.1016/j.ceb.2018.02.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 02/12/2018] [Accepted: 02/13/2018] [Indexed: 01/21/2023]
Abstract
The actin cytoskeleton is the primary force-generating machinery in the cell, which can produce pushing (protrusive) forces using energy of actin polymerization and pulling (contractile) forces via sliding of bipolar filaments of myosin II along actin filaments, as well as perform other key functions. These functions are essential for whole cell migration, cell interaction with the environment, mechanical properties of the cell surface and other key aspects of cell physiology. The actin cytoskeleton is a highly complex and dynamic system of actin filaments organized into various superstructures by multiple accessory proteins. High resolution architecture of functionally distinct actin arrays provides key clues for understanding actin cytoskeleton functions. This review summarizes recent advance in our understanding of the actin cytoskeleton ultrastructure.
Collapse
Affiliation(s)
- Tatyana M Svitkina
- Department of Biology, University of Pennsylvania, 433 S. University Avenue, Philadelphia, PA 19104, USA.
| |
Collapse
|
70
|
Merkel Cell Polyomavirus Small T Antigen Drives Cell Motility via Rho-GTPase-Induced Filopodium Formation. J Virol 2018; 92:JVI.00940-17. [PMID: 29093086 PMCID: PMC5752956 DOI: 10.1128/jvi.00940-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 10/17/2017] [Indexed: 02/07/2023] Open
Abstract
Cell motility and migration is a complex, multistep, and multicomponent process intrinsic to progression and metastasis. Motility is dependent on the activities of integrin receptors and Rho family GTPases, resulting in the remodeling of the actin cytoskeleton and formation of various motile actin-based protrusions. Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high likelihood of recurrence and metastasis. Merkel cell polyomavirus (MCPyV) is associated with the majority of MCC cases, and MCPyV-induced tumorigenesis largely depends on the expression of the small tumor antigen (ST). Since the discovery of MCPyV, a number of mechanisms have been suggested to account for replication and tumorigenesis, but to date, little is known about potential links between MCPyV T antigen expression and the metastatic nature of MCC. Previously, we described the action of MCPyV ST on the microtubule network and how it impacts cell motility and migration. Here, we demonstrate that MCPyV ST affects the actin cytoskeleton to promote the formation of filopodia through a mechanism involving the catalytic subunit of protein phosphatase 4 (PP4C). We also show that MCPyV ST-induced cell motility is dependent upon the activities of the Rho family GTPases Cdc42 and RhoA. In addition, our results indicate that the MCPyV ST-PP4C interaction results in the dephosphorylation of β1 integrin, likely driving the cell motility pathway. These findings describe a novel mechanism by which a tumor virus induces cell motility, which may ultimately lead to cancer metastasis, and provides opportunities and strategies for targeted interventions for disseminated MCC. IMPORTANCE Merkel cell polyomavirus (MCPyV) is the most recently discovered human tumor virus. It causes the majority of cases of Merkel cell carcinoma (MCC), an aggressive skin cancer. However, the molecular mechanisms implicating MCPyV-encoded proteins in cancer development are yet to be fully elucidated. This study builds upon our previous observations, which demonstrated that the MCPyV ST antigen enhances cell motility, providing a potential link between MCPyV protein expression and the highly metastatic nature of MCC. Here, we show that MCPyV ST remodels the actin cytoskeleton, promoting the formation of filopodia, which is essential for MCPyV ST-induced cell motility, and we also implicate the activity of specific Rho family GTPases, Cdc42 and RhoA, in these processes. Moreover, we describe a novel mechanism for the activation of Rho-GTPases and the cell motility pathway due to the interaction between MCPyV ST and the cellular phosphatase catalytic subunit PP4C, which leads to the specific dephosphorylation of β1 integrin. These findings may therefore provide novel strategies for therapeutic intervention for disseminated MCC.
Collapse
|
71
|
Abstract
The actin cytoskeleton-a collection of actin filaments with their accessory and regulatory proteins-is the primary force-generating machinery in the cell. It can produce pushing (protrusive) forces through coordinated polymerization of multiple actin filaments or pulling (contractile) forces through sliding actin filaments along bipolar filaments of myosin II. Both force types are particularly important for whole-cell migration, but they also define and change the cell shape and mechanical properties of the cell surface, drive the intracellular motility and morphogenesis of membrane organelles, and allow cells to form adhesions with each other and with the extracellular matrix.
Collapse
Affiliation(s)
- Tatyana Svitkina
- Department of Biology, University of Pennsylvania, 221 Leidy Labs, Philadelphia, Pennsylvania 19104
| |
Collapse
|
72
|
|
73
|
The Arp2/3 Complex Is Essential for Distinct Stages of Spine Synapse Maturation, Including Synapse Unsilencing. J Neurosci 2017; 36:9696-709. [PMID: 27629719 DOI: 10.1523/jneurosci.0876-16.2016] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/02/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Dendritic filopodia are actin-rich structures that are thought to contribute to early spine synapse formation; however, the actin regulatory proteins important for early synaptogenesis are poorly defined. Using organotypic hippocampal slice cultures and primary neuron hippocampal cultures from Arp2/3 conditional knock-out mice, we analyze the roles of the Arp2/3 complex, an actin regulator that creates branched actin networks, and demonstrate it is essential for distinct stages of both structural and functional maturation of excitatory spine synapses. Our data show that initially the Arp2/3 complex inhibits the formation of dendritic filopodia but that later during development, the Arp2/3 complex drives the morphological maturation from filopodia to typical spine morphology. Furthermore, we demonstrate that although the Arp2/3 complex is not required for key spine maturation steps, such as presynaptic contact and recruitment of MAGUK (membrane-associated guanylate kinase) scaffolding proteins or NMDA receptors, it is necessary for the recruitment of AMPA receptors. This latter process, also known as synapse unsilencing, is a final and essential step in the neurodevelopment of excitatory postsynaptic synaptogenesis, setting the stage for neuronal interconnectivity. These findings provide the first evidence that the Arp2/3 complex is directly involved in functional maturation of dendritic spines during the developmental period of spinogenesis. SIGNIFICANCE STATEMENT Excitatory spine synapse formation (spinogenesis) is a poorly understood yet pivotal period of neurodevelopment that occurs within 2-3 weeks after birth. Neurodevelopmental disorders such as intellectual disability and autism are characterized by abnormal spine structure, which may arise from abnormal excitatory synaptogenesis. The initial stage of spinogenesis is thought to begin with the emergence of actin-rich dendritic filopodia that initiate contact with presynaptic axonal boutons. However, it remains enigmatic how actin cytoskeletal regulation directs dendritic filopodial emergence or their subsequent maturation into dendritic spines during development and on into adulthood. In this study, we provide the first evidence that the Arp2/3 complex, a key actin nucleator, is involved in distinct stages of spine formation and is required for synapse unsilencing.
Collapse
|
74
|
Functional Actin Networks under Construction: The Cooperative Action of Actin Nucleation and Elongation Factors. Trends Biochem Sci 2017; 42:414-430. [DOI: 10.1016/j.tibs.2017.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 03/04/2017] [Accepted: 03/07/2017] [Indexed: 12/31/2022]
|
75
|
Kage F, Winterhoff M, Dimchev V, Mueller J, Thalheim T, Freise A, Brühmann S, Kollasser J, Block J, Dimchev G, Geyer M, Schnittler HJ, Brakebusch C, Stradal TEB, Carlier MF, Sixt M, Käs J, Faix J, Rottner K. FMNL formins boost lamellipodial force generation. Nat Commun 2017; 8:14832. [PMID: 28327544 PMCID: PMC5364437 DOI: 10.1038/ncomms14832] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/03/2017] [Indexed: 01/16/2023] Open
Abstract
Migration frequently involves Rac-mediated protrusion of lamellipodia, formed by Arp2/3 complex-dependent branching thought to be crucial for force generation and stability of these networks. The formins FMNL2 and FMNL3 are Cdc42 effectors targeting to the lamellipodium tip and shown here to nucleate and elongate actin filaments with complementary activities in vitro. In migrating B16-F1 melanoma cells, both formins contribute to the velocity of lamellipodium protrusion. Loss of FMNL2/3 function in melanoma cells and fibroblasts reduces lamellipodial width, actin filament density and -bundling, without changing patterns of Arp2/3 complex incorporation. Strikingly, in melanoma cells, FMNL2/3 gene inactivation almost completely abolishes protrusion forces exerted by lamellipodia and modifies their ultrastructural organization. Consistently, CRISPR/Cas-mediated depletion of FMNL2/3 in fibroblasts reduces both migration and capability of cells to move against viscous media. Together, we conclude that force generation in lamellipodia strongly depends on FMNL formin activity, operating in addition to Arp2/3 complex-dependent filament branching.
Collapse
Affiliation(s)
- Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Moritz Winterhoff
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Vanessa Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Jan Mueller
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Tobias Thalheim
- Soft Matter Physics Group, Institut für experimentelle Physik I, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany
| | - Anika Freise
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Stefan Brühmann
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Jana Kollasser
- Biomedical Institute, BRIC, University of Copenhagen, DK-2200 Copenhagen, Denmark.,Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Jennifer Block
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Georgi Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Matthias Geyer
- Institute of Innate Immunity, Department of Structural Immunology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany
| | - Hans-Joachim Schnittler
- Institute of Anatomy and Vascular Biology, Westfälische Wilhelms-Universität Münster, Vesaliusweg 2-4, 48149 Münster, Germany
| | - Cord Brakebusch
- Biomedical Institute, BRIC, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility Group, Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, Gif-sur-Yvette 91198, France
| | - Michael Sixt
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Josef Käs
- Soft Matter Physics Group, Institut für experimentelle Physik I, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| |
Collapse
|
76
|
Dimchev G, Steffen A, Kage F, Dimchev V, Pernier J, Carlier MF, Rottner K. Efficiency of lamellipodia protrusion is determined by the extent of cytosolic actin assembly. Mol Biol Cell 2017; 28:1311-1325. [PMID: 28331069 PMCID: PMC5426846 DOI: 10.1091/mbc.e16-05-0334] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 02/10/2017] [Accepted: 03/17/2017] [Indexed: 11/26/2022] Open
Abstract
Lamellipodia protrusion requires actin network formation driven by the Arp2/3 complex and its upstream regulators WAVE complex and Rac. Actin assembly factors of the formin and Ena/VASP families can influence protrusion, in particular by maintaining a balance between lamellipodial and cytosolic actin filament assembly. Cell migration and cell–cell communication involve the protrusion of actin-rich cell surface projections such as lamellipodia and filopodia. Lamellipodia are networks of actin filaments generated and turned over by filament branching through the Arp2/3 complex. Inhibition of branching is commonly agreed to eliminate formation and maintenance of lamellipodial actin networks, but the regulation of nucleation or elongation of Arp2/3-independent filament populations within the network by, for example, formins or Ena/VASP family members and its influence on the effectiveness of protrusion have been unclear. Here we analyzed the effects of a set of distinct formin fragments and VASP on site-specific, lamellipodial versus cytosolic actin assembly and resulting consequences on protrusion. Surprisingly, expression of formin variants but not VASP reduced lamellipodial protrusion in B16-F1 cells, albeit to variable extents. The rates of actin network polymerization followed a similar trend. Unexpectedly, the degree of inhibition of both parameters depended on the extent of cytosolic but not lamellipodial actin assembly. Indeed, excess cytosolic actin assembly prevented actin monomer from rapid translocation to and efficient incorporation into lamellipodia. Thus, as opposed to sole regulation by actin polymerases operating at their tips, the protrusion efficiency of lamellipodia is determined by a finely tuned balance between lamellipodial and cytosolic actin assembly.
Collapse
Affiliation(s)
- Georgi Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Vanessa Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Julien Pernier
- Cytoskeleton Dynamics and Motility, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany .,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| |
Collapse
|
77
|
Platinum replica electron microscopy: Imaging the cytoskeleton globally and locally. Int J Biochem Cell Biol 2017; 86:37-41. [PMID: 28323208 DOI: 10.1016/j.biocel.2017.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/20/2017] [Accepted: 03/13/2017] [Indexed: 11/21/2022]
Abstract
Structural studies reveal how smaller components of a system work together as a whole. However, combining high resolution of details with full coverage of the whole is challenging. In cell biology, light microscopy can image many cells in their entirety, but at a lower resolution, whereas electron microscopy affords very high resolution, but usually at the expense of the sample size and coverage. Structural analyses of the cytoskeleton are especially demanding, because cytoskeletal networks are unresolvable by light microscopy due to their density and intricacy, whereas their proper preservation is a challenge for electron microscopy. Platinum replica electron microscopy can uniquely bridge the gap between the "comfort zones" of light and electron microscopy by allowing high resolution imaging of the cytoskeleton throughout the entire cell and in many cells in the population. This review describes the principles and applications of platinum replica electron microscopy for studies of the cytoskeleton.
Collapse
|
78
|
Sedzinski J, Hannezo E, Tu F, Biro M, Wallingford JB. RhoA regulates actin network dynamics during apical surface emergence in multiciliated epithelial cells. J Cell Sci 2017; 130:420-428. [PMID: 28089989 PMCID: PMC5278671 DOI: 10.1242/jcs.194704] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/10/2016] [Indexed: 12/18/2022] Open
Abstract
Homeostatic replacement of epithelial cells from basal precursors is a multistep process involving progenitor cell specification, radial intercalation and, finally, apical surface emergence. Recent data demonstrate that actin-based pushing under the control of the formin protein Fmn1 drives apical emergence in nascent multiciliated epithelial cells (MCCs), but little else is known about this actin network or the control of Fmn1. Here, we explore the role of the small GTPase RhoA in MCC apical emergence. Disruption of RhoA function reduced the rate of apical surface expansion and decreased the final size of the apical domain. Analysis of cell shapes suggests that RhoA alters the balance of forces exerted on the MCC apical surface. Finally, quantitative time-lapse imaging and fluorescence recovery after photobleaching studies argue that RhoA works in concert with Fmn1 to control assembly of the specialized apical actin network in MCCs. These data provide new molecular insights into epithelial apical surface assembly and could also shed light on mechanisms of apical lumen formation.
Collapse
Affiliation(s)
- Jakub Sedzinski
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Edouard Hannezo
- Cavendish Laboratory, Department of Physics, J.J. Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, UK
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Fan Tu
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Maté Biro
- Centenary Institute of Cancer Medicine and Cell Biology, Locked Bag 6, Newtown, New South Wales 2042, Australia
- Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - John B Wallingford
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| |
Collapse
|
79
|
Lim IK, Choi JA, Kim EY, Kim BN, Jang S, Ryu MS, Shim SH. TIS21/BTG2 inhibits doxorubicin-induced stress fiber-vimentin networks via Nox4-ROS-ABI2-DRF-linked signal cascade. Cell Signal 2017; 30:179-190. [DOI: 10.1016/j.cellsig.2016.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/11/2016] [Accepted: 12/04/2016] [Indexed: 01/28/2023]
|
80
|
Bryant D, Clemens L, Allard J. Computational simulation of formin-mediated actin polymerization predicts homologue-dependent mechanosensitivity. Cytoskeleton (Hoboken) 2016; 74:29-39. [PMID: 27792274 DOI: 10.1002/cm.21344] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 10/27/2016] [Accepted: 10/27/2016] [Indexed: 01/10/2023]
Abstract
Many actin structures are nucleated and assembled by the barbed-end tracking polymerase formin family, including filopodia, focal adhesions, the cytokinetic ring and cell cortex. These structures respond to forces in distinct ways. Formins typically have profilin-actin binding sites embedded in highly flexible disordered FH1 domains, hypothesized to diffusively explore space to rapidly capture actin monomers for delivery to the barbed end. Recent experiments demonstrate that formin-mediated polymerization accelerates when under tension. The acceleration has been attributed to modifying the state of the FH2 domain of formin. Intriguingly, the same acceleration is reported when tension is applied to the FH1 domains, ostensibly pulling monomers away from the barbed end. Here we develop a mesoscale coarse-grain model of formin-mediated actin polymerization, including monomer capture and delivery by FH1, which sterically interacts with actin along its entire length. The binding of actin monomers to their specific sites on FH1 is entropically disfavored by the high disorder. We find that this penalty is attenuated when force is applied to the FH1 domain by revealing the binding site, increasing monomer capture efficiency. Overall polymerization rates can decrease or increase with increasing force, depending on the length of FH1 domain and location of binding site. Our results suggest that the widely varying FH1 lengths and binding site locations found in known formins could be used to differentially respond to force, depending on the actin structure being assembled. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Derek Bryant
- Department of Physics and Astronomy, University of California, Irvine, California
| | - Lara Clemens
- Center for Complex Biological Systems, University of California, Irvine, California
| | - Jun Allard
- Department of Physics and Astronomy, University of California, Irvine, California.,Center for Complex Biological Systems, University of California, Irvine, California.,Department of Mathematics, University of California, Irvine, California
| |
Collapse
|
81
|
Isogai T, van der Kammen R, Bleijerveld OB, Goerdayal SS, Argenzio E, Altelaar AFM, Innocenti M. Quantitative Proteomics Illuminates a Functional Interaction between mDia2 and the Proteasome. J Proteome Res 2016; 15:4624-4637. [PMID: 27769112 DOI: 10.1021/acs.jproteome.6b00718] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Formin mDia2 is a cytoskeleton-regulatory protein that switches reversibly between a closed, autoinhibited and an open, active conformation. Although the open conformation of mDia2 induces actin assembly thereby controlling many cellular processes, mDia2 possesses also actin-independent and conformation-insensitive scaffolding roles related to microtubules and p53, respectively. Thus, we hypothesize that mDia2 may have other unappreciated functions and regulatory modes. Here we identify and validate proteasome and Ubiquitin as mDia2-interacting partners using stable isotope labeling with amino acids in cell culture-based quantitative proteomics and biochemistry, respectively. Although mDia2 is ubiquitinated, binds ubiquitinated proteins and free Ubiquitin, it is not a proteasome substrate. Surprisingly, knockdown of mDia2 increases the activity of the proteasome in vitro, whereas mDia2 overexpression has opposite effects only when it adopts the open conformation and cannot induce actin assembly. Consistently, a combination of candidate and unbiased proteome-wide analyses indicates that mDia2 regulates the cellular levels of proteasome substrate β-catenin and a number of ubiquitinated actin-regulatory proteins. Hence, these findings add more complexity to the mDia2 activity cycle by showing that the open conformation may control actin dynamics also through actin-independent regulation of the proteasome.
Collapse
Affiliation(s)
| | | | | | - Soenita S Goerdayal
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University , 3584 CH Utrecht, The Netherlands
| | | | - A F Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University , 3584 CH Utrecht, The Netherlands.,Netherlands Proteomics Centre and Cancer Genomics Centre, 3584 CH Utrecht, The Netherlands
| | | |
Collapse
|
82
|
Bhaskar N, Padmavathy N, Jain S, Bose S, Basu B. Modulated in Vitro Biocompatibility of a Unique Cross-Linked Salicylic Acid-Poly(ε-caprolactone)-Based Biodegradable Polymer. ACS APPLIED MATERIALS & INTERFACES 2016; 8:29721-29733. [PMID: 27726328 DOI: 10.1021/acsami.6b10711] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Herein, we report the development of a unique architecture by chemically cross-linking salicylic acid (SA)-based poly(anhydride ester) onto a biodegradable amine-functionalized poly(caprolactone) (PCL), using lactic acid as a spacer. The ester and amide linkages in the SA-PCL polymer, synthesized through melt condensation, were confirmed by NMR and FT-IR spectroscopic techniques. The enzymatic and nonenzymatic hydrolytic degradation profile exhibited linear degradation kinetics over an extended time period (>5 weeks). The compatibility and growth of C2C12 myoblast cells were found to be significantly improved on the fast-degrading SA-PCL substrates compared to those over neat PCL and amine-functionalized PCL. Further, the decreased red blood cell damage, illustrated by 0.39% hemolysis activity and a minimal number of platelet adhesion on a SA-PCL polymeric surface confirmed good hemocompatibility of the as-synthesized polymer. Together with a moderate bactericidal property, the spectrum of properties of this novel polymer can be attributed to the synergistic effect of the presence of chemical moieties of SA and amine groups in PCL. In summary, it is considered that a SA-PCL-based cross-linked composite can be utilized as a new biodegradable polymer.
Collapse
Affiliation(s)
- Nitu Bhaskar
- Laboratory for Biomaterials, Materials Research Centre, ‡Department of Materials Engineering, and ⊥Center for Biosystems Science and Engineering, Indian Institute of Science , Bangalore 560012, India
| | - Nagarajan Padmavathy
- Laboratory for Biomaterials, Materials Research Centre, ‡Department of Materials Engineering, and ⊥Center for Biosystems Science and Engineering, Indian Institute of Science , Bangalore 560012, India
| | - Shubham Jain
- Laboratory for Biomaterials, Materials Research Centre, ‡Department of Materials Engineering, and ⊥Center for Biosystems Science and Engineering, Indian Institute of Science , Bangalore 560012, India
| | - Suryasarathi Bose
- Laboratory for Biomaterials, Materials Research Centre, ‡Department of Materials Engineering, and ⊥Center for Biosystems Science and Engineering, Indian Institute of Science , Bangalore 560012, India
| | - Bikramjit Basu
- Laboratory for Biomaterials, Materials Research Centre, ‡Department of Materials Engineering, and ⊥Center for Biosystems Science and Engineering, Indian Institute of Science , Bangalore 560012, India
| |
Collapse
|
83
|
Sedzinski J, Hannezo E, Tu F, Biro M, Wallingford JB. Emergence of an Apical Epithelial Cell Surface In Vivo. Dev Cell 2016; 36:24-35. [PMID: 26766441 DOI: 10.1016/j.devcel.2015.12.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/07/2015] [Accepted: 12/10/2015] [Indexed: 12/22/2022]
Abstract
Epithelial sheets are crucial components of all metazoan animals, enclosing organs and protecting the animal from its environment. Epithelial homeostasis poses unique challenges, as addition of new cells and loss of old cells must be achieved without disrupting the fluid-tight barrier and apicobasal polarity of the epithelium. Several studies have identified cell biological mechanisms underlying extrusion of cells from epithelia, but far less is known of the converse mechanism by which new cells are added. Here, we combine molecular, pharmacological, and laser-dissection experiments with theoretical modeling to characterize forces driving emergence of an apical surface as single nascent cells are added to a vertebrate epithelium in vivo. We find that this process involves the interplay between cell-autonomous actin-generated pushing forces in the emerging cell and mechanical properties of neighboring cells. Our findings define the forces driving this cell behavior, contributing to a more comprehensive understanding of epithelial homeostasis.
Collapse
Affiliation(s)
- Jakub Sedzinski
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Edouard Hannezo
- Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK; Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Fan Tu
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Maté Biro
- Centenary Institute of Cancer Medicine and Cell Biology, Locked Bag 6, Newtown, NSW 2042, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
| | - John B Wallingford
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Patterson Labs, University of Texas, 2401 Speedway, Austin, TX 78712, USA.
| |
Collapse
|
84
|
Swaney KF, Li R. Function and regulation of the Arp2/3 complex during cell migration in diverse environments. Curr Opin Cell Biol 2016; 42:63-72. [PMID: 27164504 DOI: 10.1016/j.ceb.2016.04.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 02/06/2023]
Abstract
As the first de novo actin nucleator discovered, the Arp2/3 complex has been a central player in models of protrusive force production via the dynamic actin network. Here, we review recent studies on the functional role of the Arp2/3 complex in the migration of diverse cell types in different migratory environments. These findings have revealed an unexpected level of plasticity, both in how cells rely on the Arp2/3 complex for migration and other physiological functions and in the intricate modulation of the Arp2/3 complex by other actin regulators and upstream signaling cascades.
Collapse
Affiliation(s)
- Kristen F Swaney
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 450 Rangos Building, Baltimore, MD 21205, USA; Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, 3400 North Charles Street, 100 Croft Hall, Baltimore, MD 21218, USA.
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 450 Rangos Building, Baltimore, MD 21205, USA; Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, 3400 North Charles Street, 100 Croft Hall, Baltimore, MD 21218, USA
| |
Collapse
|
85
|
Davidson AJ, Wood W. Unravelling the Actin Cytoskeleton: A New Competitive Edge? Trends Cell Biol 2016; 26:569-576. [PMID: 27133808 PMCID: PMC4961066 DOI: 10.1016/j.tcb.2016.04.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/31/2016] [Accepted: 04/04/2016] [Indexed: 12/27/2022]
Abstract
Dynamic rearrangements in the actin cytoskeleton underlie a wide range of cell behaviours, which in turn contribute to many aspects of human health including embryogenesis, cancer metastasis, wound healing, and inflammation. Precise control of the actin cytoskeleton requires the coordinated activity of a diverse set of different actin regulators. However, our current understanding of the actin cytoskeleton has focused on how individual actin regulatory pathways function in isolation from one another. Recently, competition has emerged as a means by which different actin assembly factors can influence each other's activity at the cellular level. Here such findings will be used to explore the possibility that competition within the actin cytoskeleton confers cellular plasticity and the ability to prioritise multiple conflicting stimuli. Cells maintain a dynamic actin cytoskeleton by carefully balancing the activities of a diverse collection of actin regulators. Recent findings suggest that key actin assembly factors limit one another through competition over a finite pool of G-actin. Increasing or decreasing cellular G-actin influences the type of F-actin network generated. The actin monomer binding protein profilin is responsible for proportioning how much G-actin is available to each assembly factor. Cytoskeletal competition appears universally conserved from yeast to human. Competition ensures cytoskeletal homeostasis and integration/coordination between the different actin regulatory pathways to support dynamic cell behaviour.
Collapse
Affiliation(s)
- Andrew J Davidson
- School of Cellular and Molecular Medicine, Faculty of Biomedical Sciences, Biomedical Science Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Will Wood
- School of Cellular and Molecular Medicine, Faculty of Biomedical Sciences, Biomedical Science Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
| |
Collapse
|
86
|
Cortical actin and the plasma membrane: inextricably intertwined. Curr Opin Cell Biol 2016; 38:81-9. [PMID: 26986983 DOI: 10.1016/j.ceb.2016.02.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/09/2016] [Accepted: 02/25/2016] [Indexed: 11/22/2022]
Abstract
The plasma membrane serves as a barrier, separating the cell from its external environment. Simultaneously it acts as a site for information transduction, entry of nutrients, receptor signaling, and adapts to the shape of the cell. This requires local control of organization at multiple scales in this heterogeneous fluid lipid bilayer with a plethora of proteins and a closely juxtaposed dynamic cortical cytoskeleton. New membrane models highlight the influence of the underlying cortical actin on the diffusion of membrane components. Myosin motors as well as proteins that remodel actin filaments have additionally been implicated in defining the organization of many membrane constituents. Here we provide a perspective of the intimate relationship of the membrane lipid matrix and the underlying cytoskeleton.
Collapse
|
87
|
Monzo P, Chong YK, Guetta-Terrier C, Krishnasamy A, Sathe SR, Yim EKF, Ng WH, Ang BT, Tang C, Ladoux B, Gauthier NC, Sheetz MP. Mechanical confinement triggers glioma linear migration dependent on formin FHOD3. Mol Biol Cell 2016; 27:1246-61. [PMID: 26912794 PMCID: PMC4831879 DOI: 10.1091/mbc.e15-08-0565] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/18/2016] [Indexed: 12/12/2022] Open
Abstract
Glioblastomas are extremely aggressive brain tumors with highly invasive properties. Brain linear tracks such as blood vessel walls constitute their main invasive routes. Here we analyze rat C6 and patient-derived glioma cell motility in vitro using micropatterned linear tracks to mimic blood vessels. On laminin-coated tracks (3-10 μm), these cells used an efficient saltatory mode of migration similar to their in vivo migration. This saltatory migration was also observed on larger tracks (50-400 μm in width) at high cell densities. In these cases, the mechanical constraints imposed by neighboring cells triggered this efficient mode of migration, resulting in the formation of remarkable antiparallel streams of cells along the tracks. This motility involved microtubule-dependent polarization, contractile actin bundles and dynamic paxillin-containing adhesions in the leading process and in the tail. Glioma linear migration was dramatically reduced by inhibiting formins but, surprisingly, accelerated by inhibiting Arp2/3. Protein expression and phenotypic analysis indicated that the formin FHOD3 played a role in this motility but not mDia1 or mDia2. We propose that glioma migration under confinement on laminin relies on formins, including FHOD3, but not Arp2/3 and that the low level of adhesion allows rapid antiparallel migration.
Collapse
Affiliation(s)
- Pascale Monzo
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | | | | | - Anitha Krishnasamy
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Sharvari R Sathe
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Evelyn K F Yim
- Mechanobiology Institute, National University of Singapore, Singapore 117411 Department of Biomedical Engineering, National University of Singapore, Singapore 117575 Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228
| | - Wai Hoe Ng
- National Neuroscience Institute, Singapore 308433 Duke-NUS Graduate Medical School, Singapore 169857
| | - Beng Ti Ang
- National Neuroscience Institute, Singapore 308433 Duke-NUS Graduate Medical School, Singapore 169857 Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597 Singapore Institute for Clinical Sciences, A*STAR, Singapore 117609
| | - Carol Tang
- National Neuroscience Institute, Singapore 308433 Duke-NUS Graduate Medical School, Singapore 169857 Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore 169610
| | - Benoit Ladoux
- Mechanobiology Institute, National University of Singapore, Singapore 117411 Institut Jacques Monod, Université Paris Diderot and CNRS UMR 7592, 75205 Paris, France
| | - Nils C Gauthier
- Mechanobiology Institute, National University of Singapore, Singapore 117411 National Neuroscience Institute, Singapore 308433
| | - Michael P Sheetz
- Mechanobiology Institute, National University of Singapore, Singapore 117411 Department of Biological Sciences, Columbia University, New York, NY 10027
| |
Collapse
|
88
|
Zeng Y, Xie H, Qiao Y, Wang J, Zhu X, He G, Li Y, Ren X, Wang F, Liang L, Ding Y. Formin-like2 regulates Rho/ROCK pathway to promote actin assembly and cell invasion of colorectal cancer. Cancer Sci 2016; 106:1385-93. [PMID: 26258642 PMCID: PMC4638017 DOI: 10.1111/cas.12768] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 07/16/2015] [Accepted: 08/02/2015] [Indexed: 12/26/2022] Open
Abstract
Formin-like2 (FMNL2) is a member of the diaphanous-related formins family, which act as effectors and upstream modulators of Rho GTPases signaling and control the actin-dependent processes, such as cell motility or invasion. FMNL2 has been identified as promoting the motility and metastasis in colorectal carcinoma (CRC). However, whether FMNL2 regulates Rho signaling to promote cancer cell invasion remains unclear. In this study, we demonstrated an essential role for FMNL2 in the activations of Rho/ROCK pathway, SRF transcription or actin assembly, and subsequent CRC cell invasion. FMNL2 could activate Rho/ROCK pathway, and required ROCK to promote CRC cell invasion. Moreover, FMNL2 promoted the formation of filopodia and stress fiber, and activated the SRF transcription in a Rho-dependent manner. We also demonstrated that FMNL2 was necessary for LPA-induced invasion, RhoA/ROCK activation, actin assembly and SRF activation. FMNL2 was an essential component of LPA signal transduction toward RhoA by directly interacting with LARG. LARG silence inhibited RhoA/ROCK pathway and CRC cell invasion. Collectively, these data indicate that FMNL2, acting as upstream of RhoA by interacting with LARG, can promote actin assembly and CRC cell invasion through a Rho/ROCK-dependent mechanism.
Collapse
Affiliation(s)
- Yuanfeng Zeng
- Department of Pathology, Southern Medical University, Guangzhou, China.,Department of Pathology, the People's Hospital, Nanchang, China
| | - Huijun Xie
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yudan Qiao
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Jianmei Wang
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Xiling Zhu
- Department of Pathology, Southern Medical University, Guangzhou, China.,Department of Oncology, General Hospital of Armed Police Forces, Beijing, China
| | - Guoyang He
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yuling Li
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Xiaoli Ren
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Feifei Wang
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Li Liang
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yanqing Ding
- Department of Pathology, Southern Medical University, Guangzhou, China.,Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| |
Collapse
|
89
|
Skau CT, Waterman CM. Specification of Architecture and Function of Actin Structures by Actin Nucleation Factors. Annu Rev Biophys 2016; 44:285-310. [PMID: 26098516 DOI: 10.1146/annurev-biophys-060414-034308] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The actin cytoskeleton is essential for diverse processes in mammalian cells; these processes range from establishing cell polarity to powering cell migration to driving cytokinesis to positioning intracellular organelles. How these many functions are carried out in a spatiotemporally regulated manner in a single cytoplasm has been the subject of much study in the cytoskeleton field. Recent work has identified a host of actin nucleation factors that can build architecturally diverse actin structures. The biochemical properties of these factors, coupled with their cellular location, likely define the functional properties of actin structures. In this article, we describe how recent advances in cell biology and biochemistry have begun to elucidate the role of individual actin nucleation factors in generating distinct cellular structures. We also consider how the localization and orientation of actin nucleation factors, in addition to their kinetic properties, are critical to their ability to build a functional actin cytoskeleton.
Collapse
Affiliation(s)
- Colleen T Skau
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892; ,
| | | |
Collapse
|
90
|
Lehtimäki J, Hakala M, Lappalainen P. Actin Filament Structures in Migrating Cells. Handb Exp Pharmacol 2016; 235:123-152. [PMID: 27469496 DOI: 10.1007/164_2016_28] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell migration is necessary for several developmental processes in multicellular organisms. Furthermore, many physiological processes such as wound healing and immunological events in adult animals are dependent on cell migration. Consequently, defects in cell migration are linked to various diseases including immunological disorders as well as cancer progression and metastasis formation. Cell migration is driven by specific protrusive and contractile actin filament structures, but the types and relative contributions of these actin filament arrays vary depending on the cell type and the environment of the cell. In this chapter, we introduce the most important actin filament structures that contribute to mesenchymal and amoeboid cell migration modes and discuss the mechanisms by which the assembly and turnover of these structures are controlled by various actin-binding proteins.
Collapse
Affiliation(s)
- Jaakko Lehtimäki
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Markku Hakala
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland.
| |
Collapse
|
91
|
Steffen A, Stradal TEB, Rottner K. Signalling Pathways Controlling Cellular Actin Organization. Handb Exp Pharmacol 2016; 235:153-178. [PMID: 27757765 DOI: 10.1007/164_2016_35] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The actin cytoskeleton is essential for morphogenesis and virtually all types of cell shape changes. Reorganization is per definition driven by continuous disassembly and re-assembly of actin filaments, controlled by major, ubiquitously operating machines. These are specifically employed by the cell to tune its activities in accordance with respective environmental conditions or to satisfy specific needs.Here we sketch some fundamental signalling pathways established to contribute to the reorganization of specific actin structures at the plasma membrane. Rho-family GTPases are at the core of these pathways, and dissection of their precise contributions to actin reorganization in different cell types and tissues will thus continue to improve our understanding of these important signalling nodes. Furthermore, we will draw your attention to the emerging theme of actin reorganization on intracellular membranes, its functional relation to Rho-GTPase signalling, and its relevance for the exciting phenomenon autophagy.
Collapse
Affiliation(s)
- Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.,Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany
| |
Collapse
|
92
|
Abstract
The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm playing critical roles in cell motility, shape generation, and mechanical properties of a cell. Fibrillar polymers-actin filaments, microtubules, and intermediate filaments-are major constituents of the cytoskeleton, which constantly change their organization during cellular activities. The actin cytoskeleton is especially polymorphic, as actin filaments can form multiple higher order assemblies performing different functions. Structural information about cytoskeleton organization is critical for understanding its functions and mechanisms underlying various forms of cellular activity. Because of the nanometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a key tool to determine the structure of the cytoskeleton. This article describes application of rotary shadowing (or metal replica) EM for visualization of the cytoskeleton. The procedure is applicable to thin cultured cells growing on glass coverslips and consists of detergent extraction of cells to expose their cytoskeleton, chemical fixation to provide stability, ethanol dehydration and critical point drying to preserve three-dimensionality, rotary shadowing with platinum to create contrast, and carbon coating to stabilize replicas. This technique provides easily interpretable three-dimensional images, in which individual cytoskeletal fibers are clearly resolved, and individual proteins can be identified by immunogold labeling. More importantly, replica EM is easily compatible with live cell imaging, so that one can correlate the dynamics of a cell or its components, e.g., expressed fluorescent proteins, with high resolution structural organization of the cytoskeleton in the same cell.
Collapse
|
93
|
Draga M, Scaal M, Pröls F. Signaling filopodia in avian embryogenesis: formation and function. AIMS MOLECULAR SCIENCE 2016. [DOI: 10.3934/molsci.2016.4.683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
94
|
Ozawa S, Ueda S, Imamura H, Mori K, Asanuma K, Yanagita M, Nakagawa T. Glycolysis, but not Mitochondria, responsible for intracellular ATP distribution in cortical area of podocytes. Sci Rep 2015; 5:18575. [PMID: 26677804 PMCID: PMC4683464 DOI: 10.1038/srep18575] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 11/23/2015] [Indexed: 12/15/2022] Open
Abstract
Differentiated podocytes, a type of renal glomerular cells, require substantial levels of energy to maintain glomerular physiology. Mitochondria and glycolysis are two major producers of ATP, but the precise roles of each in podocytes remain unknown. This study evaluated the roles of mitochondria and glycolysis in differentiated and differentiating podocytes. Mitochondria in differentiated podocytes are located in the central part of cell body while blocking mitochondria had minor effects on cell shape and migratory ability. In contrast, blocking glycolysis significantly reduced the formation of lamellipodia, a cortical area of these cells, decreased the cell migratory ability and induced the apoptosis. Consistently, the local ATP production in lamellipodia was predominantly regulated by glycolysis. In turn, synaptopodin expression was ameliorated by blocking either mitochondrial respiration or glycolysis. Similar to differentiated podocytes, the differentiating podocytes utilized the glycolysis for regulating apoptosis and lamellipodia formation while synaptopodin expression was likely involved in both mitochondrial OXPHOS and glycolysis. Finally, adult mouse podocytes have most of mitochondria predominantly in the center of the cytosol whereas phosphofructokinase, a rate limiting enzyme for glycolysis, was expressed in foot processes. These data suggest that mitochondria and glycolysis play parallel but distinct roles in differentiated and differentiating podocytes.
Collapse
Affiliation(s)
- Shota Ozawa
- TMK project, Medical Innovation Center, Kyoto University, Kyoto, Japan.,Pharmacology Research Laboratories II, Mitsubishi Tanabe Pharma Corporation, Saitama, Japan
| | - Shuko Ueda
- Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Hiromi Imamura
- Laboratory of Functional Biology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kiyoshi Mori
- TMK project, Medical Innovation Center, Kyoto University, Kyoto, Japan
| | - Katsuhiko Asanuma
- TMK project, Medical Innovation Center, Kyoto University, Kyoto, Japan
| | - Motoko Yanagita
- TMK project, Medical Innovation Center, Kyoto University, Kyoto, Japan.,Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takahiko Nakagawa
- TMK project, Medical Innovation Center, Kyoto University, Kyoto, Japan
| |
Collapse
|
95
|
Salinas RP, Ortiz Flores RM, Distel JS, Aguilera MO, Colombo MI, Berón W. Coxiella burnetii Phagocytosis Is Regulated by GTPases of the Rho Family and the RhoA Effectors mDia1 and ROCK. PLoS One 2015; 10:e0145211. [PMID: 26674774 PMCID: PMC4682630 DOI: 10.1371/journal.pone.0145211] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 12/01/2015] [Indexed: 01/09/2023] Open
Abstract
The GTPases belonging to the Rho family control the actin cytoskeleton rearrangements needed for particle internalization during phagocytosis. ROCK and mDia1 are downstream effectors of RhoA, a GTPase involved in that process. Coxiella burnetii, the etiologic agent of Q fever, is internalized by the host´s cells in an actin-dependent manner. Nevertheless, the molecular mechanism involved in this process has been poorly characterized. This work analyzes the role of different GTPases of the Rho family and some downstream effectors in the internalization of C. burnetii by phagocytic and non-phagocytic cells. The internalization of C. burnetii into HeLa and RAW cells was significantly inhibited when the cells were treated with Clostridium difficile Toxin B which irreversibly inactivates members of the Rho family. In addition, the internalization was reduced in HeLa cells that overexpressed the dominant negative mutants of RhoA, Rac1 or Cdc42 or that were knocked down for the Rho GTPases. The pharmacological inhibition or the knocking down of ROCK diminished bacterium internalization. Moreover, C. burnetii was less efficiently internalized in HeLa cells overexpressing mDia1-N1, a dominant negative mutant of mDia1, while the overexpression of the constitutively active mutant mDia1-ΔN3 increased bacteria uptake. Interestingly, when HeLa and RAW cells were infected, RhoA, Rac1 and mDia1 were recruited to membrane cell fractions. Our results suggest that the GTPases of the Rho family play an important role in C. burnetii phagocytosis in both HeLa and RAW cells. Additionally, we present evidence that ROCK and mDia1, which are downstream effectors of RhoA, are involved in that process.
Collapse
Affiliation(s)
- Romina P. Salinas
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Rodolfo M. Ortiz Flores
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Jesús S. Distel
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Milton O. Aguilera
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - María I. Colombo
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
| | - Walter Berón
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo—CONICET, Mendoza, 5500, Argentina
- * E-mail:
| |
Collapse
|
96
|
Shrivastava A, Prasad A, Kuzontkoski PM, Yu J, Groopman JE. Slit2N Inhibits Transmission of HIV-1 from Dendritic Cells to T-cells by Modulating Novel Cytoskeletal Elements. Sci Rep 2015; 5:16833. [PMID: 26582347 PMCID: PMC4652184 DOI: 10.1038/srep16833] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 10/20/2015] [Indexed: 11/30/2022] Open
Abstract
Dendritic cells are among the first cells to encounter sexually acquired human immunodeficiency virus (HIV-1), in the mucosa, and they can transmit HIV-1 to CD4(+) T-cells via an infectious synapse. Recent studies reveal that actin-rich membrane extensions establish direct contact between cells at this synapse and facilitate virus transmission. Genesis of these contacts involves signaling through c-Src and Cdc42, which modulate actin polymerization and filopodia formation via the Arp2/3 complex and Diaphanous 2 (Diaph2). We found that Slit2N, a ligand for the Roundabout (Robo) receptors, blocked HIV-1-induced signaling through Arp2/3 and Diaph2, decreased filopodial extensions on dendritic cells, and inhibited cell-to-cell transmission of HIV-1 in a Robo1-dependent manner. Employing proteomic analysis, we identified Flightless-1 as a novel, Robo1-interacting protein. Treatment with shRNAs reduced levels of Flightless-1 and demonstrated its role in efficient cell-to-cell transfer of HIV-1. These results suggest a novel strategy to limit viral infection in the host by targeting the Slit/Robo pathway with modulation of cytoskeletal elements previously unrecognized in HIV-1 transmission.
Collapse
Affiliation(s)
- Ashutosh Shrivastava
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Anil Prasad
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Paula M. Kuzontkoski
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
- DynaMed, EBSCO Information Services, 10 Estes Street, Ipswich, Massachusetts, USA
| | - Jinlong Yu
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
- Department of Psychiatry, Mclean Hospital, Harvard Medical School, 115 Mill Street, Belmont, Massachusetts, USA
| | - Jerome E. Groopman
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
97
|
Shekhar S, Kerleau M, Kühn S, Pernier J, Romet-Lemonne G, Jégou A, Carlier MF. Formin and capping protein together embrace the actin filament in a ménage à trois. Nat Commun 2015; 6:8730. [PMID: 26564775 PMCID: PMC4660058 DOI: 10.1038/ncomms9730] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/24/2015] [Indexed: 11/09/2022] Open
Abstract
Proteins targeting actin filament barbed ends play a pivotal role in motile processes. While formins enhance filament assembly, capping protein (CP) blocks polymerization. On their own, they both bind barbed ends with high affinity and very slow dissociation. Their barbed-end binding is thought to be mutually exclusive. CP has recently been shown to be present in filopodia and controls their morphology and dynamics. Here we explore how CP and formins may functionally coregulate filament barbed-end assembly. We show, using kinetic analysis of individual filaments by microfluidics-assisted fluorescence microscopy, that CP and mDia1 formin are able to simultaneously bind barbed ends. This is further confirmed using single-molecule imaging. Their mutually weakened binding enables rapid displacement of one by the other. We show that formin FMNL2 behaves similarly, thus suggesting that this is a general property of formins. Implications in filopodia regulation and barbed-end structural regulation are discussed.
Collapse
Affiliation(s)
- Shashank Shekhar
- Cytoskeleton Dynamics and Cell Motility, Department of Biochemistry, Biophysics and Structural Biology, I2BC, CNRS, 91198 Gif-sur-Yvette, France
| | - Mikael Kerleau
- Cytoskeleton Dynamics and Cell Motility, Department of Biochemistry, Biophysics and Structural Biology, I2BC, CNRS, 91198 Gif-sur-Yvette, France
| | - Sonja Kühn
- Cytoskeleton Dynamics and Cell Motility, Department of Biochemistry, Biophysics and Structural Biology, I2BC, CNRS, 91198 Gif-sur-Yvette, France
| | - Julien Pernier
- Cytoskeleton Dynamics and Cell Motility, Department of Biochemistry, Biophysics and Structural Biology, I2BC, CNRS, 91198 Gif-sur-Yvette, France
| | - Guillaume Romet-Lemonne
- Cytoskeleton Dynamics and Cell Motility, Department of Biochemistry, Biophysics and Structural Biology, I2BC, CNRS, 91198 Gif-sur-Yvette, France
| | - Antoine Jégou
- Cytoskeleton Dynamics and Cell Motility, Department of Biochemistry, Biophysics and Structural Biology, I2BC, CNRS, 91198 Gif-sur-Yvette, France
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Cell Motility, Department of Biochemistry, Biophysics and Structural Biology, I2BC, CNRS, 91198 Gif-sur-Yvette, France
| |
Collapse
|
98
|
An Y, Ma C, Tian C, Zhao L, Pang L, Tu Q, Xu J, Wang J. On-chip assay of the effect of topographical microenvironment on cell growth and cell-cell interactions during wound healing. BIOMICROFLUIDICS 2015; 9:064112. [PMID: 26649132 PMCID: PMC4670448 DOI: 10.1063/1.4936927] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 06/05/2023]
Abstract
Wound healing is an essential physiological process for tissue homeostasis, involving multiple types of cells, extracellular matrices, and growth factor/chemokine interactions. Many in vitro studies have investigated the interactions between cues mentioned above; however, most of them only focused on a single factor. In the present study, we design a wound healing device to recapitulate in vivo complex microenvironments and heterogeneous cell situations to investigate how three types of physiologically related cells interact with their microenvironments around and with each other during a wound healing process. Briefly, a microfluidic device with a micropillar substrate, where diameter and interspacing can be tuned to mimic the topographical features of the 3D extracellular matrix, was designed to perform positional cell loading on the micropillar substrate, co-culture of three types of physiologically related cells, keratinocytes, dermal fibroblasts, and human umbilical vein endothelial cells, as well as an investigation of their interactions during wound healing. The result showed that cell attachment, morphology, cytoskeleton distribution, and nucleus shape were strongly affected by the micropillars, and these cells showed collaborative response to heal the wound. Taken together, these findings highlight the dynamic relationship between cells and their microenvironments. Also, this reproducible device may facilitate the in vitro investigation of numerous physiological and pathological processes such as cancer metastasis, angiogenesis, and tissue engineering.
Collapse
Affiliation(s)
| | - Chao Ma
- Colleges of Science and Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, People's Republic of China
| | - Chang Tian
- Colleges of Science and Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, People's Republic of China
| | - Lei Zhao
- Colleges of Science and Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, People's Republic of China
| | - Long Pang
- Colleges of Science and Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, People's Republic of China
| | - Qin Tu
- Colleges of Science and Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, People's Republic of China
| | - Juan Xu
- Colleges of Science and Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, People's Republic of China
| | - Jinyi Wang
- Colleges of Science and Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, People's Republic of China
| |
Collapse
|
99
|
Shao X, Kawauchi K, Shivashankar GV, Bershadsky AD. Novel localization of formin mDia2: importin β-mediated delivery to and retention at the cytoplasmic side of the nuclear envelope. Biol Open 2015; 4:1569-75. [PMID: 26519515 PMCID: PMC4728353 DOI: 10.1242/bio.013649] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The formin family proteins are important regulators of actin polymerization that are involved in many cellular processes. However, little is known about their specific cellular localizations. Here, we show that Diaphanous-related formin-3 (mDia2) localizes to the cytoplasmic side of the nuclear envelope. This localization of mDia2 to the nuclear rim required the presence of a nuclear localization signal (NLS) sequence at the mDia2 N-terminal. Consistent with this result, super-resolution images demonstrated that at the nuclear rim, mDia2 co-localized with the nuclear pore complexes and a nuclear transport receptor, importin β. Furthermore, an interaction between mDia2 and importin β was detected by immunoprecipitation, and silencing of importin β was shown to attenuate accumulation of mDia2 to the nuclear rim. We have shown previously that Ca2+ entry leads to the assembly of perinuclear actin rim in an inverted formin 2 (INF2) dependent manner. mDia2, however, was not involved in this process since abolishing its localization at the nuclear rim by silencing of importin β had no effect on actin assembly at the nuclear rim triggered by Ca2+ stimulation. Summary: Formin mDia2 accumulates to the cytoplasmic side of the nuclear envelope and co-localizes with the nuclear pore complexes in an importin β-dependent manner.
Collapse
Affiliation(s)
- Xiaowei Shao
- Mechanobiology Institute, National University of Singapore, 117411, Singapore
| | - Keiko Kawauchi
- Mechanobiology Institute, National University of Singapore, 117411, Singapore Frontiers of Innovative Research in Science and Technology, Konan University, Kobe 650-0047, Japan
| | - G V Shivashankar
- Mechanobiology Institute, National University of Singapore, 117411, Singapore Department of Biological Sciences, National University of Singapore, 117543, Singapore FIRC Institute of Molecular Oncology, Milan 20139, Italy
| | - Alexander D Bershadsky
- Mechanobiology Institute, National University of Singapore, 117411, Singapore Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
100
|
Young LE, Heimsath EG, Higgs HN. Cell type-dependent mechanisms for formin-mediated assembly of filopodia. Mol Biol Cell 2015; 26:4646-59. [PMID: 26446836 PMCID: PMC4678021 DOI: 10.1091/mbc.e15-09-0626] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/01/2015] [Indexed: 11/11/2022] Open
Abstract
Filopodia are finger-like protrusions from the plasma membrane and are of fundamental importance to cellular physiology, but the mechanisms governing their assembly are still in question. One model, called convergent elongation, proposes that filopodia arise from Arp2/3 complex-nucleated dendritic actin networks, with factors such as formins elongating these filaments into filopodia. We test this model using constitutively active constructs of two formins, FMNL3 and mDia2. Surprisingly, filopodial assembly requirements differ between suspension and adherent cells. In suspension cells, Arp2/3 complex is required for filopodial assembly through either formin. In contrast, a subset of filopodia remains after Arp2/3 complex inhibition in adherent cells. In adherent cells only, mDia1 and VASP also contribute to filopodial assembly, and filopodia are disproportionately associated with focal adhesions. We propose an extension of the existing models for filopodial assembly in which any cluster of actin filament barbed ends in proximity to the plasma membrane, either Arp2/3 complex dependent or independent, can initiate filopodial assembly by specific formins.
Collapse
Affiliation(s)
- Lorna E Young
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Ernest G Heimsath
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| |
Collapse
|