101
|
Amicis AD, Sanctis SD, Cristofaro SD, Franchini V, Lista F, Regalbuto E, Giovenale E, Gallerano GP, Nenzi P, Bei R, Fantini M, Benvenuto M, Masuelli L, Coluzzi E, Cicia C, Sgura A. Biological effects of in vitro THz radiation exposure in human foetal fibroblasts. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 793:150-60. [DOI: 10.1016/j.mrgentox.2015.06.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/05/2015] [Indexed: 11/26/2022]
|
102
|
Wang HB, Yan HC, Liu Y. Clinical significance of ECT2 expression in tissue and serum of gastric cancer patients. Clin Transl Oncol 2015; 18:735-42. [PMID: 26497353 DOI: 10.1007/s12094-015-1428-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/09/2015] [Indexed: 01/29/2023]
Abstract
The ECT2 (epithelial cell transforming sequence 2) oncogene acted as a guanine nucleotide exchange factor for RhoGTPases, and regulates cytokinesis; thus, it may play a role in the pathogenesis of gastric cancer. In this study, we investigated the expression ECT2 gene in tissues and serum of gastric cancer patients to explore its clinical significance. ECT2 mRNA expression levels in tissues and serum were examined by RT-PCR, and ECT2 protein expression in tissue was evaluated by Western blot, and was further validated by immunohistochemistry and enzyme-linked immunosorbent assay at serum level. ECT2 level was significantly increased in the GC tissues and serum compared to normal control. ECT2 expression was positively correlated with the histologic differentiation, stages of TNM, and lymph node metastasis in GC (P < 0.05). Our results suggest that ECT2 plays an important role during GC progression and it may become a new diagnostic marker and therapeutic molecular target for management of GC.
Collapse
Affiliation(s)
- H-B Wang
- Department of Oncology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China.
| | - H-C Yan
- Department of Oncology, The Second People's Hospital of Lianyungang, Lianyungang, Jiangsu, China
| | - Y Liu
- Jiangsu Key Laboratory of Biological Cancer Therapy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| |
Collapse
|
103
|
Wortzel I, Hanoch T, Porat Z, Hausser A, Seger R. Mitotic Golgi translocation of ERK1c is mediated by a PI4KIIIβ-14-3-3γ shuttling complex. J Cell Sci 2015; 128:4083-95. [PMID: 26459638 DOI: 10.1242/jcs.170910] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023] Open
Abstract
Golgi fragmentation is a highly regulated process that allows division of the Golgi complex between the two daughter cells. The mitotic reorganization of the Golgi is accompanied by a temporary block in Golgi functioning, as protein transport in and out of the Golgi stops. Our group has previously demonstrated the involvement of the alternatively spliced variants ERK1c and MEK1b (ERK1 is also known as MAPK3, and MEK1 as MAP2K1) in mitotic Golgi fragmentation. We had also found that ERK1c translocates to the Golgi at the G2 to M phase transition, but the molecular mechanism underlying this recruitment remains unknown. In this study, we narrowed the translocation timing to prophase and prometaphase, and elucidated its molecular mechanism. We found that CDK1 phosphorylates Ser343 of ERK1c, thereby allowing the binding of phosphorylated ERK1c to a complex that consists of PI4KIIIβ (also known as PI4KB) and the 14-3-3γ dimer (encoded by YWHAB). The stability of the complex is regulated by protein kinase D (PKD)-mediated phosphorylation of PI4KIIIβ. The complex assembly induces the Golgi shuttling of ERK1c, where it is activated by MEK1b, and induces Golgi fragmentation. Our work shows that protein shuttling to the Golgi is not completely abolished at the G2 to M phase transition, thus integrating several independent Golgi-regulating processes into one coherent pathway.
Collapse
Affiliation(s)
- Inbal Wortzel
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tamar Hanoch
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ziv Porat
- Department of Biological Services, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Angelika Hausser
- University of Stuttgart, Institute of Cell Biology and Immunology, Stuttgart 70550, Germany
| | - Rony Seger
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 7610001, Israel
| |
Collapse
|
104
|
Campa CC, Martini M, De Santis MC, Hirsch E. How PI3K-derived lipids control cell division. Front Cell Dev Biol 2015; 3:61. [PMID: 26484344 PMCID: PMC4588110 DOI: 10.3389/fcell.2015.00061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/14/2015] [Indexed: 01/18/2023] Open
Abstract
To succeed in cell division, intense cytoskeletal and membrane remodeling are required to allow accurate chromosome segregation and cytoplasm partitioning. Spatial restriction of the actin dynamics and vesicle trafficking define the cell symmetry and equivalent membrane scission events, respectively. Protein complexes coordinating mitosis are recruited to membrane microdomains characterized by the presence of the phosphatidylinositol lipid members (PtdIns), like PtdIns(3,4,5)P3,PtdIns(4,5)P2, and PtdIns(3)P. These PtdIns represent a minor component of cell membranes, defining membrane domain identity, ultimately controlling cytoskeleton and membrane dynamics during mitosis. The coordinated presence of PtdIns(3,4,5)P3 at the cell poles and PtdIns(4,5)P2 at the cleavage furrow controls the polarity of the actin cytoskeleton leading to symmetrical cell division. In the endosomal compartment, the trafficking of PtdIns(3)P positive vesicles allows the recruitment of the protein machinery required for the abscission.
Collapse
Affiliation(s)
- Carlo C Campa
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
| | - Miriam Martini
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
| | - Maria C De Santis
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
| | - Emilio Hirsch
- Department of Molecular Biotechnology and Health Sciences, University of Turin Torino, Italy
| |
Collapse
|
105
|
Dzafic E, Strzyz PJ, Wilsch-Bräuninger M, Norden C. Centriole Amplification in Zebrafish Affects Proliferation and Survival but Not Differentiation of Neural Progenitor Cells. Cell Rep 2015; 13:168-182. [PMID: 26411683 DOI: 10.1016/j.celrep.2015.08.062] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/05/2015] [Accepted: 08/21/2015] [Indexed: 11/17/2022] Open
Abstract
In animal cells, supernumerary centrosomes, resulting from centriole amplification, cause mitotic aberrations and have been associated with diseases, including microcephaly and cancer. To evaluate how centriole amplification impacts organismal development at the cellular and tissue levels, we used the in vivo imaging potential of the zebrafish. We demonstrate that centriole amplification can induce multipolar anaphase, resulting in binucleated cells. Such binucleation causes substantial apoptosis in the neuroepithelium. Interestingly, not all epithelia are similarly sensitive to binucleation, as skin cells tolerate it without entering apoptosis. In the neuroepithelium, however, binucleation leads to tissue degeneration and subsequent organismal death. Notably, this tissue degeneration can be efficiently counterbalanced by compensatory proliferation of wild-type cells. Because the risk for generating a binucleated daughter recurs at every cell division, centriole amplification in the neuroepithelium is especially deleterious during progenitor proliferation. Once cells reach the differentiation phase, however, centriole amplification does not impair neuronal differentiation.
Collapse
Affiliation(s)
- Edo Dzafic
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Paulina J Strzyz
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
| | - Michaela Wilsch-Bräuninger
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Caren Norden
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
| |
Collapse
|
106
|
Yeh CM, Sung WW, Lai HW, Hsieh MJ, Yen HH, Su TC, Chang WH, Chen CY, Ko JL, Chen CJ. Opposing prognostic roles of nuclear and cytoplasmic RACGAP1 expression in colorectal cancer patients. Hum Pathol 2015; 47:45-51. [PMID: 26508373 DOI: 10.1016/j.humpath.2015.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 08/19/2015] [Accepted: 09/02/2015] [Indexed: 01/26/2023]
Abstract
Rac GTPase activating protein 1 (RACGAP1) plays a regulatory role in initiation of cytokinesis, control of cell growth and differentiation, and tumor malignancy, making it a potential prognostic biomarker. RACGAP1 is present in the nucleus, but a diffuse distribution in the cytoplasm also occurs. The aim of this study was to determine the impact of nuclear and cytoplasmic expression of RACGAP1 on clinical outcome to provide further evidence of a role in colorectal cancer. RACGAP1 expression was analyzed by immunohistochemistry in 166 cancer specimens from primary colorectal cancer patients. The mean follow-up time after surgery was 5.4 years (range, 0.01-13.10 years). The prognostic value of RACGAP1 on overall survival was validated by Kaplan-Meier analysis and Cox regression models. RACGAP1 is expressed in colorectal specimen and is present in both the nucleus and cytoplasm in different amounts. Colorectal cancer patients had opposite prognoses depending on the site of RACGAP1 expression. Patients with high nuclear RACGAP1 expression had poor outcomes, whereas those with high cytoplasmic RACGAP1 expression had favorable prognosis (P = .003 and P = .001, respectively). Patients with low nuclear but high cytoplasmic RACGAP1 expression had better survival compared with those with other combinations (P < .001). We suggest that RACGAP1 expression levels in the nucleus and cytoplasm, determined by immunohistochemical staining, predict opposite clinical outcomes and that both could be independent prognostic markers for colorectal cancer.
Collapse
Affiliation(s)
- Chung-Min Yeh
- Department of Surgical Pathology, Changhua Christian Hospital, Changhua 50006, Taiwan; Department of Medical Technology, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 35664, Taiwan
| | - Wen-Wei Sung
- Department of Medical Technology, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 35664, Taiwan; School of Medicine, Chung Shan Medical University, Taichung 40242, Taiwan; Department of Medical Education, Chung Shan Medical University Hospital, Taichung 40242, Taiwan
| | - Hung-Wen Lai
- Department of Surgery, Changhua Christian Hospital, Changhua 50006, Taiwan; School of Medicine, National Yang Ming University, Taipei 11221, Taiwan
| | - Ming-Ju Hsieh
- Cancer Research Center, Changhua Christian Hospital, Changhua 50006, Taiwan; School of Optometry, Chung Shan Medical University, Taichung 40242, Taiwan; Institute of Medicine, Chung Shan Medical University, Taichung 40242, Taiwan
| | - Hsu-Heng Yen
- School of Medicine, Chung Shan Medical University, Taichung 40242, Taiwan; Department of Gastroenterology, Changhua Christian Hospital, Changhua 50006, Taiwan
| | - Tzu-Cheng Su
- Department of Surgical Pathology, Changhua Christian Hospital, Changhua 50006, Taiwan
| | - Wei-Hsiang Chang
- Department of Surgical Pathology, Changhua Christian Hospital, Changhua 50006, Taiwan
| | - Chia-Yu Chen
- Department of Surgical Pathology, Changhua Christian Hospital, Changhua 50006, Taiwan
| | - Jiunn-Liang Ko
- Institute of Medicine, Chung Shan Medical University, Taichung 40242, Taiwan; Department of Medical Oncology and Chest Medicine, Chung Shan Medical University Hospital, Taichung 40242, Taiwan
| | - Chih-Jung Chen
- Department of Surgical Pathology, Changhua Christian Hospital, Changhua 50006, Taiwan; Department of Medical Technology, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 35664, Taiwan; School of Medicine, Chung Shan Medical University, Taichung 40242, Taiwan.
| |
Collapse
|
107
|
Abstract
The establishment and maintenance of epithelial cell-cell junctions is crucially important to regulate adhesion, apico-basal polarity and motility of epithelial cells, and ultimately controls the architecture and physiology of epithelial organs. Junctions are supported, shaped and regulated by cytoskeletal filaments, whose dynamic organization and contractility are finely tuned by GTPases of the Rho family, primarily RhoA, Rac1 and Cdc42. Recent research has identified new molecular mechanisms underlying the cross-talk between these GTPases and epithelial junctions. Here we briefly summarize the current knowledge about the organization, molecular evolution and cytoskeletal anchoring of cell-cell junctions, and we comment on the most recent advances in the characterization of the interactions between Rho GTPases and junctional proteins, and their consequences with regards to junction assembly and regulation of cell behavior in vertebrate model systems. The concept of “zonular signalosome” is proposed, which highlights the close functional relationship between proteins of zonular junctions (zonulae occludentes and adhaerentes) and the control of cytoskeletal organization and signaling through Rho GTPases, transcription factors, and their effectors.
Collapse
Key Words
- AJ, adherens junction
- AMOT, angiomotin
- AMPK, Adenosine Monophosphate-Activated Protein Kinase
- APC, adenomatous poliposis coli
- CD2AP, CD2-associated protein
- CGN, cingulin
- CGNL1, paracingulin
- Cdc42
- Cdc42, cell division cycle 42
- DLC, deleted in liver cancer
- Dbl, diffuse B-cell lymphoma
- EPLIN, epithelial protein lost in neoplasm
- ERK, extracellular regulated kinase
- FERM, four.point.one, ezrin, radixin, moesin
- FGD5, FYVE, RhoGEF and PH domain containing 5
- GAP, GTPase activating protein
- GEF, guanine nucleotide exchange factor
- GST, glutathione -S- transferase; JAM = junctional adhesion molecule
- MCF-7, Michigan Cancer Foundation - 7
- MDCK, Madin Darby Canine Kidney
- MKLP1, mitotic kinesin-like protein-1
- MRCK, myotonic dystrophy-related Cdc42-binding kinase
- MgcRacGAP, male germ cell racGAP
- PA, puncta adhaerentia
- PAK, p21-activated kinase; PATJ, Pals1 associated tight junction protein
- PCNA, proliferating cell nuclear antigen
- PDZ, Post synaptic density protein (PSD95), Drosophila, disc large tumour suppressor (DlgA), and zonula occludens-1
- PLEKHA7, pleckstrin homology domain containing, family A member 7
- RICH-1, RhoGAP interacting with CIP4 homologues
- ROCK, Rho-associated protein kinase
- Rac
- Rho
- SH3BP1, (SH3 domain 490 binding protein-1)
- TJ, tight junction
- Tbx-3, T-box-3
- Tiam, Tumor invasion and metastasis
- WASP, Wiskott-Aldrich Syndrome Protein
- WAVE, WASP family Verprolin-homologous protein
- ZA, zonula adhaerens
- ZO, zonula occludens
- ZONAB, (ZO-1)–associated nucleic acid binding protein.
- cytoseleton
- epithelium
- junctions
Collapse
Affiliation(s)
- Sandra Citi
- a Department of Cell Biology ; University of Geneva ; Geneva , Switzerland
| | | | | | | |
Collapse
|
108
|
Delabre U, Feld K, Crespo E, Whyte G, Sykes C, Seifert U, Guck J. Deformation of phospholipid vesicles in an optical stretcher. SOFT MATTER 2015; 11:6075-88. [PMID: 26135540 DOI: 10.1039/c5sm00562k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Phospholipid vesicles are common model systems for cell membranes. Important aspects of the membrane function relate to its mechanical properties. Here we have investigated the deformation behaviour of phospholipid vesicles in a dual-beam laser trap, also called an optical stretcher. This study explicitly makes use of the inherent heating present in such traps to investigate the dependence of vesicle deformation on temperature. By using lasers with different wavelengths, optically induced mechanical stresses and temperature increase can be tuned fairly independently with a single setup. The phase transition temperature of vesicles can be clearly identified by an increase in deformation. In the case of no heating effects, a minimal model for drop deformation in an optical stretcher and a more specific model for vesicle deformation that takes explicitly into account the angular dependence of the optical stress are presented to account for the experimental results. Elastic constants are extracted from the fitting procedures, which agree with literature data. This study demonstrates the utility of optical stretching, which is easily combined with microfluidic delivery, for the future serial, high-throughput study of the mechanical and thermodynamic properties of phospholipid vesicles.
Collapse
Affiliation(s)
- Ulysse Delabre
- Univ. Bordeaux, CNRS, Laboratoire Ondes et Matière d'Aquitaine, UMR 5798, F-33400 Talence, France.
| | | | | | | | | | | | | |
Collapse
|
109
|
Rodrigues NTL, Lekomtsev S, Jananji S, Kriston-Vizi J, Hickson GRX, Baum B. Kinetochore-localized PP1-Sds22 couples chromosome segregation to polar relaxation. Nature 2015; 524:489-92. [PMID: 26168397 DOI: 10.1038/nature14496] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/16/2015] [Indexed: 02/06/2023]
Abstract
Cell division requires the precise coordination of chromosome segregation and cytokinesis. This coordination is achieved by the recruitment of an actomyosin regulator, Ect2, to overlapping microtubules at the centre of the elongating anaphase spindle. Ect2 then signals to the overlying cortex to promote the assembly and constriction of an actomyosin ring between segregating chromosomes. Here, by studying division in proliferating Drosophila and human cells, we demonstrate the existence of a second, parallel signalling pathway, which triggers the relaxation of the polar cell cortex at mid anaphase. This is independent of furrow formation, centrosomes and microtubules and, instead, depends on PP1 phosphatase and its regulatory subunit Sds22 (refs 2, 3). As separating chromosomes move towards the polar cortex at mid anaphase, kinetochore-localized PP1-Sds22 helps to break cortical symmetry by inducing the dephosphorylation and inactivation of ezrin/radixin/moesin proteins at cell poles. This promotes local softening of the cortex, facilitating anaphase elongation and orderly cell division. In summary, this identifies a conserved kinetochore-based phosphatase signal and substrate, which function together to link anaphase chromosome movements to cortical polarization, thereby coupling chromosome segregation to cell division.
Collapse
Affiliation(s)
- Nelio T L Rodrigues
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Sergey Lekomtsev
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Silvana Jananji
- Sainte-Justine Hospital Research Center, Montréal, Québec H3T 1C5, Canada
| | - Janos Kriston-Vizi
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Gilles R X Hickson
- Sainte-Justine Hospital Research Center, Montréal, Québec H3T 1C5, Canada.,Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.,Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK.,CelTisPhyBio Labex, Institut Curie, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| |
Collapse
|
110
|
Chen J, Xia H, Zhang X, Karthik S, Pratap SV, Ooi LL, Hong W, Hui KM. ECT2 regulates the Rho/ERK signalling axis to promote early recurrence in human hepatocellular carcinoma. J Hepatol 2015; 62:1287-95. [PMID: 25617497 DOI: 10.1016/j.jhep.2015.01.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 12/09/2014] [Accepted: 01/08/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Early recurrence is the major obstacle for improving the outcome of patients with hepatocellular carcinoma (HCC). Therefore, identifying key molecules contributing to early HCC recurrence can enable the development of novel therapeutic strategies for the clinical management of HCC. Epithelial cell transforming sequence 2 (ECT2) has been implicated in human cancers, but its function in HCC is largely unknown. METHODS ECT2 expression was studied by microarrays, immunoblotting and immunohistochemistry in human HCC samples. siRNA- and lentiviral vector-mediated knockdown were employed to decipher the molecular functions of ECT2. RESULTS The upregulation of ECT2 is significantly associated with early recurrent HCC disease and poor survival. Knockdown of ECT2 markedly suppressed Rho GTPases activities, enhanced apoptosis, attenuated oncogenicity and reduced the metastatic ability of HCC cells. Moreover, knockdown of ECT2 or Rho also suppressed ERK activation, while the silencing of Rho or ERK led to a marked reduction in cell migration. Stable knockdown of ECT2 in vivo resulted in significant retardation of tumour growth and the suppression of ERK activation. High expression of ECT2 correlates with high ERK phosphorylation and poor survival of HCC patients. Furthermore, ECT2 enhances the expression and stability of RACGAP1, accelerating ECT2-mediated Rho activation to promote metastasis. CONCLUSIONS ECT2 is closely associated with the activation of the Rho/ERK signalling axis to promote early HCC recurrence. In addition, ECT2 can crosstalk with RACGAP1 to catalyse the GTP exchange involved in Rho signalling to further regulate tumour initiation and metastasis.
Collapse
Affiliation(s)
- Jianxiang Chen
- Laboratory of Cancer Genomics, Division of Cellular and Molecular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore, Singapore
| | - Hongping Xia
- Laboratory of Cancer Genomics, Division of Cellular and Molecular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore, Singapore
| | - Xiaoqian Zhang
- Institute of Molecular and Cell Biology, A(∗)STAR, Biopolis Drive Proteos, Singapore, Singapore
| | - Sekar Karthik
- Laboratory of Cancer Genomics, Division of Cellular and Molecular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore, Singapore
| | - Seshachalam Veerabrahma Pratap
- Laboratory of Cancer Genomics, Division of Cellular and Molecular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore, Singapore
| | - London Lucien Ooi
- Division of Surgical Oncology, National Cancer Centre, Singapore 169610, Singapore
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, A(∗)STAR, Biopolis Drive Proteos, Singapore, Singapore
| | - Kam M Hui
- Laboratory of Cancer Genomics, Division of Cellular and Molecular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore, Singapore; Institute of Molecular and Cell Biology, A(∗)STAR, Biopolis Drive Proteos, Singapore, Singapore; Cancer & Stem Cell Biology Program, Duke-National University of Singapore Graduate Medical School, Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| |
Collapse
|
111
|
Wesolowska N, Lénárt P. Nuclear roles for actin. Chromosoma 2015; 124:481-9. [PMID: 25944357 DOI: 10.1007/s00412-015-0519-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 10/23/2022]
Abstract
Actin's presence in the nucleus is a subject that has ignited a lot of controversy in the past. With our review, we attempt to reach out not only to the specialists but also to a broader audience that might be skeptical in light of the controversies. We take a rather conservative approach to build an argument that recent studies provide multiple independent lines of evidence substantiating actin's diverse nuclear functions, especially in its monomeric state. We then particularly focus on how the concentration of monomeric actin, and potentially of specific polymerized forms of actin, can be used by the cell as indicators of cellular state and how this information can be transduced into the nucleus by transcriptional regulators, eliciting a response. We also provide examples that in specific cell types and specific physiological conditions, actin is functional in the nucleus in its polymeric form. However, we also discuss that in many instances, the presence of actin regulators in the nucleus, which is often seen as proof of their function within this compartment, may simply reflect an additional means of their regulation by compartmentalization.
Collapse
Affiliation(s)
- Natalia Wesolowska
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Péter Lénárt
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany.
| |
Collapse
|
112
|
Chan CJ, Ekpenyong AE, Golfier S, Li W, Chalut KJ, Otto O, Elgeti J, Guck J, Lautenschläger F. Myosin II Activity Softens Cells in Suspension. Biophys J 2015; 108:1856-69. [PMID: 25902426 PMCID: PMC4407259 DOI: 10.1016/j.bpj.2015.03.009] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 02/26/2015] [Accepted: 03/04/2015] [Indexed: 01/08/2023] Open
Abstract
The cellular cytoskeleton is crucial for many cellular functions such as cell motility and wound healing, as well as other processes that require shape change or force generation. Actin is one cytoskeleton component that regulates cell mechanics. Important properties driving this regulation include the amount of actin, its level of cross-linking, and its coordination with the activity of specific molecular motors like myosin. While studies investigating the contribution of myosin activity to cell mechanics have been performed on cells attached to a substrate, we investigated mechanical properties of cells in suspension. To do this, we used multiple probes for cell mechanics including a microfluidic optical stretcher, a microfluidic microcirculation mimetic, and real-time deformability cytometry. We found that nonadherent blood cells, cells arrested in mitosis, and naturally adherent cells brought into suspension, stiffen and become more solidlike upon myosin inhibition across multiple timescales (milliseconds to minutes). Our results hold across several pharmacological and genetic perturbations targeting myosin. Our findings suggest that myosin II activity contributes to increased whole-cell compliance and fluidity. This finding is contrary to what has been reported for cells attached to a substrate, which stiffen via active myosin driven prestress. Our results establish the importance of myosin II as an active component in modulating suspended cell mechanics, with a functional role distinctly different from that for substrate-adhered cells.
Collapse
Affiliation(s)
- Chii J Chan
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Andrew E Ekpenyong
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Stefan Golfier
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Wenhong Li
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Kevin J Chalut
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Wellcome Trust/Medical Research Council Stem Cell Institute, Cambridge, United Kingdom
| | - Oliver Otto
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Jens Elgeti
- Institute of Complex Systems, Forschungszentrum Jülich, Jülich, Germany
| | - Jochen Guck
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Franziska Lautenschläger
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Department of Physics, Saarland University, Saarbrücken, Germany.
| |
Collapse
|
113
|
Vogel CJ, Smit MA, Maddalo G, Possik PA, Sparidans RW, van der Burg SH, Verdegaal EM, Heck AJR, Samatar AA, Beijnen JH, Altelaar AFM, Peeper DS. Cooperative induction of apoptosis in NRAS mutant melanoma by inhibition of MEK and ROCK. Pigment Cell Melanoma Res 2015; 28:307-17. [PMID: 25728708 DOI: 10.1111/pcmr.12364] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 02/25/2015] [Indexed: 12/13/2022]
Abstract
No effective targeted therapy is currently available for NRAS mutant melanoma. Experimental MEK inhibition is rather toxic and has only limited efficacy in clinical trials. At least in part, this is caused by the emergence of drug resistance, which is commonly seen for single agent treatment and shortens clinical responses. Therefore, there is a dire need to identify effective companion drug targets for NRAS mutant melanoma. Here, we show that at concentrations where single drugs had little effect, ROCK inhibitors GSK269962A or Fasudil, in combination with either MEK inhibitor GSK1120212 (Trametinib) or ERK inhibitor SCH772984 cooperatively caused proliferation inhibition and cell death in vitro. Simultaneous inhibition of MEK and ROCK caused induction of BimEL , PARP, and Puma, and hence apoptosis. In vivo, MEK and ROCK inhibition suppressed growth of established tumors. Our findings warrant clinical investigation of the effectiveness of combinatorial targeting of MAPK/ERK and ROCK in NRAS mutant melanoma.
Collapse
Affiliation(s)
- Celia J Vogel
- Division of Molecular Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
114
|
Jing J, Chen L, Fu HY, Fan K, Yao Q, Ge YF, Lu JC, Yao B. Annexin V-induced rat Leydig cell proliferation involves Ect2 via RhoA/ROCK signaling pathway. Sci Rep 2015; 5:9437. [PMID: 25807302 PMCID: PMC5380157 DOI: 10.1038/srep09437] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/04/2015] [Indexed: 01/01/2023] Open
Abstract
This study investigated the effect of annexin V on the proliferation of primary rat Leydig cells and the potential mechanism. Our results showed that annexin V promoted rat Leydig cell proliferation and cell cycle progression in a dose- and time-dependent manner. Increased level of annexin V also enhanced Ect2 protein expression. However, siRNA knockdown of Ect2 attenuated annexin V-induced proliferation of rat Leydig cells. Taken together, these data suggest that increased level of annexin V induced rat Leydig cell proliferation and cell cycle progression via Ect2. Since RhoA activity was increased following Ect2 activation, we further investigated whether Ect2 was involved in annexin V-induced proliferation via the RhoA/ROCK pathway, and the results showed that annexin V increased RhoA activity too, and this effect was abolished by the knockdown of Ect2. Moreover, inhibition of the RhoA/ROCK pathway by a ROCK inhibitor, Y27632, also attenuated annexin V-induced proliferation and cell cycle progression. We thus conclude that Ect2 is involved in annexin V-induced rat Leydig cell proliferation through the RhoA/ROCK pathway.
Collapse
Affiliation(s)
- Jun Jing
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Li Chen
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Hai-Yan Fu
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Kai Fan
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Qi Yao
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Yi-Feng Ge
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Jin-Chun Lu
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Bing Yao
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| |
Collapse
|
115
|
Jacob S, Zhu Y, Kraft R, Cotto C, Carmical JR, Wood TG, Enkhbaatar P, Herndon DN, Hawkins HK, Cox RA. Physiologic and molecular changes in the tracheal epithelium of rats following burn injury. INTERNATIONAL JOURNAL OF BURNS AND TRAUMA 2015; 5:36-45. [PMID: 26064800 PMCID: PMC4448086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/10/2015] [Indexed: 06/04/2023]
Abstract
Pneumonia is the leading complication in the critical care of burn victims. Airway epithelial dysfunction compromises host defense against pneumonia. The aim of this study is to test the hypothesis that burn injury alters the physiology of the airway epithelium. A rat model of 60% TBSA third degree scald burn was used. At 24 hours after injury, tracheal epithelial ultrastructure was studied using transmission electron microscopy (TEM) and proliferation was measured by Ki67 immunohistochemistry. Mucociliary clearance (MCC) was measured using fluorescent microspheres. The level of malondialdehyde (MDA), an indicator of lipid peroxidation, was also measured. Changes in epithelial mRNA expression were measured using microarray. Burn injury led to a ten-fold reduction in MCC that was statistically significant (p = 0.007) 24 hours after injury. No significant change was noted in the morphology of tracheal epithelial cells between groups, although a marginal increase in extracellular space was noted in injured animals. Ki67 nuclear expression was significantly reduced (25%, p = 0.008) in injured rats. There was a significant increase in MDA levels in the epithelial lysate of burned animals, p = 0.001. Microarray analysis identified 59 genes with significant differences between sham and injured animals. Burn injury altered multiple important functions in rat tracheal epithelium. The decrease in MCC and cell proliferation may be due to oxidative injury. Mechanistic studies to identify physiological processes associated with changes in airway function may help in designing therapeutic agents to reduce burn-induced airway pathogenesis.
Collapse
Affiliation(s)
- Sam Jacob
- Departmentof Pathology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Yong Zhu
- Departmentof Pathology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Robert Kraft
- Departmentof Surgery, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Christopher Cotto
- Departmentof Pathology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Joseph R Carmical
- Departmentof Biochemistry and Molecular Biology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Thomas G Wood
- Departmentof Biochemistry and Molecular Biology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Perenlei Enkhbaatar
- Departmentof Anesthesiology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - David N Herndon
- Departmentof Surgery, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Hal K Hawkins
- Departmentof Pathology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| | - Robert A Cox
- Departmentof Pathology, Shriners Hospitals for Children and The University of Texas Medical BranchGalveston, Texas, USA
| |
Collapse
|
116
|
Rosa A, Vlassaks E, Pichaud F, Baum B. Ect2/Pbl acts via Rho and polarity proteins to direct the assembly of an isotropic actomyosin cortex upon mitotic entry. Dev Cell 2015; 32:604-16. [PMID: 25703349 PMCID: PMC4359025 DOI: 10.1016/j.devcel.2015.01.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 10/06/2014] [Accepted: 01/14/2015] [Indexed: 02/06/2023]
Abstract
Entry into mitosis is accompanied by profound changes in cortical actomyosin organization. Here, we delineate a pathway downstream of the RhoGEF Pbl/Ect2 that directs this process in a model epithelium. Our data suggest that the release of Pbl/Ect2 from the nucleus at mitotic entry drives Rho-dependent activation of Myosin-II and, in parallel, induces a switch from Arp2/3 to Diaphanous-mediated cortical actin nucleation that depends on Cdc42, aPKC, and Par6. At the same time, the mitotic relocalization of these apical protein complexes to more lateral cell surfaces enables Cdc42/aPKC/Par6 to take on a mitosis-specific function—aiding the assembly of a relatively isotropic metaphase cortex. Together, these data reveal how the repolarization and remodeling of the actomyosin cortex are coordinated upon entry into mitosis to provide cells with the isotropic and rigid form they need to undergo faithful chromosome segregation and division in a crowded tissue environment. Pbl/Ect2 drives a shift in epithelial polarity upon entry into mitosis Lateral spreading of Cdc42/aPKC/Par6 aids assembly of an isotropic metaphase cortex Mitosis triggers a switch from Arp2/3 to Dia-mediated cortical actin nucleation
Collapse
Affiliation(s)
- André Rosa
- MRC Laboratory of Molecular Cell Biology, UCL, Gower Street, London WC1E 6BT, UK; Graduate Program in Areas of Basic and Applied Biology (GABBA), University of Porto, 4200-465 Porto, Portugal
| | - Evi Vlassaks
- MRC Laboratory of Molecular Cell Biology, UCL, Gower Street, London WC1E 6BT, UK
| | - Franck Pichaud
- MRC Laboratory of Molecular Cell Biology, UCL, Gower Street, London WC1E 6BT, UK
| | - Buzz Baum
- MRC Laboratory of Molecular Cell Biology, UCL, Gower Street, London WC1E 6BT, UK.
| |
Collapse
|
117
|
Leite F, Way M. The role of signalling and the cytoskeleton during Vaccinia Virus egress. Virus Res 2015; 209:87-99. [PMID: 25681743 DOI: 10.1016/j.virusres.2015.01.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/26/2015] [Accepted: 01/26/2015] [Indexed: 01/25/2023]
Abstract
Viruses are obligate intracellular parasites that are critically dependent on their hosts to replicate and generate new progeny. To achieve this goal, viruses have evolved numerous elegant strategies to subvert and utilise the different cellular machineries and processes of their unwilling hosts. Moreover, they often accomplish this feat with a surprisingly limited number of proteins. Among the different systems of the cell, the cytoskeleton is often one of the first to be hijacked as it provides a convenient transport system for viruses to reach their site of replication with relative ease. At the latter stages of their replication cycle, the cytoskeleton also provides an efficient means for newly assembled viral progeny to reach the plasma membrane and leave the infected cell. In this review we discuss how Vaccinia virus takes advantage of the microtubule and actin cytoskeletons of its host to promote the spread of infection into neighboring cells. In particular, we highlight how analysis of actin-based motility of Vaccinia has provided unprecedented insights into how a phosphotyrosine-based signalling network is assembled and functions to stimulate Arp2/3 complex-dependent actin polymerization. We also suggest that the formin FHOD1 promotes actin-based motility of the virus by capping the fast growing ends of actin filaments rather than directly promoting filament assembly. We have come a long way since 1976, when electron micrographs of vaccinia-infected cells implicated the actin cytoskeleton in promoting viral spread. Nevertheless, there are still many unanswered questions concerning the role of signalling and the host cytoskeleton in promoting viral spread and pathogenesis.
Collapse
Affiliation(s)
- Flavia Leite
- Cell Motility Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Michael Way
- Cell Motility Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK.
| |
Collapse
|
118
|
Otto O, Rosendahl P, Mietke A, Golfier S, Herold C, Klaue D, Girardo S, Pagliara S, Ekpenyong A, Jacobi A, Wobus M, Töpfner N, Keyser UF, Mansfeld J, Fischer-Friedrich E, Guck J. Real-time deformability cytometry: on-the-fly cell mechanical phenotyping. Nat Methods 2015; 12:199-202, 4 p following 202. [DOI: 10.1038/nmeth.3281] [Citation(s) in RCA: 442] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 12/23/2014] [Indexed: 12/22/2022]
|
119
|
Cdk1-dependent mitotic enrichment of cortical myosin II promotes cell rounding against confinement. Nat Cell Biol 2015; 17:148-59. [DOI: 10.1038/ncb3098] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/17/2014] [Indexed: 12/16/2022]
|
120
|
Suzuki K, Sako K, Akiyama K, Isoda M, Senoo C, Nakajo N, Sagata N. Identification of non-Ser/Thr-Pro consensus motifs for Cdk1 and their roles in mitotic regulation of C2H2 zinc finger proteins and Ect2. Sci Rep 2015; 5:7929. [PMID: 25604483 PMCID: PMC4300507 DOI: 10.1038/srep07929] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 12/22/2014] [Indexed: 11/09/2022] Open
Abstract
The cyclin B-dependent protein kinase Cdk1 is a master regulator of mitosis and phosphorylates numerous proteins on the minimal consensus motif Ser/Thr-Pro (S/T-P). At least in several proteins, however, not well-defined motifs lacking a Pro in the +1 position, referred herein to as non-S/T-P motifs, have been shown to be phosphorylated by Cdk1. Here we show that non-S/T-P motifs in fact form consensus sequences for Cdk1 and probably play roles in mitotic regulation of physiologically important proteins. First, we show, by in vitro kinase assays, that previously identified non-S/T-P motifs all harbour one or more C-terminal Arg/Lys residues essential for their phosphorylation by Cdk1. Second, using Arg/Lys-scanning oriented peptide libraries, we demonstrate that Cdk1 phosphorylates a minimal sequence S/T-X-X-R/K and more favorable sequences (P)-X-S/T-X-[R/K]2–5 as its non-S/T-P consensus motifs. Third, on the basis of these results, we find that highly conserved linkers (typically, T-G-E-K-P) of C2H2 zinc finger proteins and a nuclear localization signal-containing sequence (matching P-X-S-X-[R/K]5) of the cytokinesis regulator Ect2 are inhibitorily phosphorylated by Cdk1, well accounting for the known mitotic regulation and function of the respective proteins. We suggest that non-S/T-P Cdk1 consensus motifs identified here may function to regulate many other proteins during mitosis.
Collapse
Affiliation(s)
- Kazuhiro Suzuki
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Kosuke Sako
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Kazuhiro Akiyama
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Michitaka Isoda
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Chiharu Senoo
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Nobushige Nakajo
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Noriyuki Sagata
- Department of Biology, Graduate School of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| |
Collapse
|
121
|
A narrow window of cortical tension guides asymmetric spindle positioning in the mouse oocyte. Nat Commun 2015; 6:6027. [PMID: 25597399 DOI: 10.1038/ncomms7027] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 12/02/2014] [Indexed: 01/17/2023] Open
Abstract
Cell mechanics control the outcome of cell division. In mitosis, external forces applied on a stiff cortex direct spindle orientation and morphogenesis. During oocyte meiosis on the contrary, spindle positioning depends on cortex softening. How changes in cortical organization induce cortex softening has not yet been addressed. Furthermore, the range of tension that allows spindle migration remains unknown. Here, using artificial manipulation of mouse oocyte cortex as well as theoretical modelling, we show that cortical tension has to be tightly regulated to allow off-center spindle positioning: a too low or too high cortical tension both lead to unsuccessful spindle migration. We demonstrate that the decrease in cortical tension required for spindle positioning is fine-tuned by a branched F-actin network that triggers the delocalization of myosin-II from the cortex, which sheds new light on the interplay between actin network architecture and cortex tension.
Collapse
|
122
|
Abstract
Cell shape is determined by cellular mechanics. Cell deformations in animal cells, such as those required for cell migration, division or epithelial morphogenesis, are largely controlled by changes in mechanical stress and tension at the cell surface. The plasma membrane and the actomyosin cortex control surface mechanics and determine cell surface tension. Tension in the actomyosin cortex primarily arises from myosin-generated stresses and depends strongly on the ultrastructural architecture of the network. Plasma membrane tension is controlled mainly by the surface area of the membrane relative to cell volume and can be modulated by changing membrane composition, shape and the organization of membrane-associated proteins. We review here our current understanding of the control of cortex and membrane tension by molecular processes. We particularly highlight the need for studies that bridge the scales between microscopic events and emergent properties at the cellular level. Finally, we discuss how the mechanical interplay between membrane dynamics and cortex contractility is key to understanding the biomechanical control of cell morphogenesis.
Collapse
|
123
|
Holmes D, Whyte G, Bailey J, Vergara-Irigaray N, Ekpenyong A, Guck J, Duke T. Separation of blood cells with differing deformability using deterministic lateral displacement(†). Interface Focus 2014; 4:20140011. [PMID: 25485078 PMCID: PMC4213443 DOI: 10.1098/rsfs.2014.0011] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Determining cell mechanical properties is increasingly recognized as a marker-free way to characterize and separate biological cells. This emerging realization has led to the development of a plethora of appropriate measurement techniques. Here, we use a fairly novel approach, deterministic lateral displacement (DLD), to separate blood cells based on their mechanical phenotype with high throughput. Human red blood cells were treated chemically to alter their membrane deformability and the effect of this alteration on the hydrodynamic behaviour of the cells in a DLD device was investigated. Cells of defined stiffness (glutaraldehyde cross-linked erythrocytes) were used to test the performance of the DLD device across a range of cell stiffness and applied shear rates. Optical stretching was used as an independent method for quantifying the variation in stiffness of the cells. Lateral displacement of cells flowing within the device, and their subsequent exit position from the device were shown to correlate with cell stiffness. Data showing how the isolation of leucocytes from whole blood varies with applied shear rate are also presented. The ability to sort leucocyte sub-populations (T-lymphocytes and neutrophils), based on a combination of cell size and deformability, demonstrates the potential for using DLD devices to perform continuous fractionation and/or enrichment of leucocyte sub-populations from whole blood.
Collapse
Affiliation(s)
- David Holmes
- London Centre for Nanotechnology , University College London , 17-19 Gordon Street, London WC1H 0AH , UK
| | - Graeme Whyte
- Friedrich-Alexander Universität Erlangen-Nürnberg , Henkestrasse 91, 91052 Erlangen , Germany ; Cavendish Laboratory, Department of Physics , University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE , UK
| | - Joe Bailey
- London Centre for Nanotechnology , University College London , 17-19 Gordon Street, London WC1H 0AH , UK ; Centre for Mathematics and Physics in the Life Sciences and Experimental Biology , University College London , Gower Street, London WC1E 6BT , UK
| | - Nuria Vergara-Irigaray
- London Centre for Nanotechnology , University College London , 17-19 Gordon Street, London WC1H 0AH , UK ; Department of Genetics, Evolution and Environment, Institute of Healthy Ageing , University College London , Gower Street, London WC1E 6BT , UK
| | - Andrew Ekpenyong
- Cavendish Laboratory, Department of Physics , University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE , UK ; Biotechnology Center , TechnischeUniversität Dresden , Tatzberg 47/49, 01307 Dresden , Germany
| | - Jochen Guck
- Cavendish Laboratory, Department of Physics , University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE , UK ; Biotechnology Center , TechnischeUniversität Dresden , Tatzberg 47/49, 01307 Dresden , Germany
| | - Tom Duke
- London Centre for Nanotechnology , University College London , 17-19 Gordon Street, London WC1H 0AH , UK
| |
Collapse
|
124
|
Özlü N, Qureshi MH, Toyoda Y, Renard BY, Mollaoglu G, Özkan NE, Bulbul S, Poser I, Timm W, Hyman AA, Mitchison TJ, Steen JA. Quantitative comparison of a human cancer cell surface proteome between interphase and mitosis. EMBO J 2014; 34:251-65. [PMID: 25476450 DOI: 10.15252/embj.201385162] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The cell surface is the cellular compartment responsible for communication with the environment. The interior of mammalian cells undergoes dramatic reorganization when cells enter mitosis. These changes are triggered by activation of the CDK1 kinase and have been studied extensively. In contrast, very little is known of the cell surface changes during cell division. We undertook a quantitative proteomic comparison of cell surface-exposed proteins in human cancer cells that were tightly synchronized in mitosis or interphase. Six hundred and twenty-eight surface and surface-associated proteins in HeLa cells were identified; of these, 27 were significantly enriched at the cell surface in mitosis and 37 in interphase. Using imaging techniques, we confirmed the mitosis-selective cell surface localization of protocadherin PCDH7, a member of a family with anti-adhesive roles in embryos. We show that PCDH7 is required for development of full mitotic rounding pressure at the onset of mitosis. Our analysis provided basic information on how cell cycle progression affects the cell surface. It also provides potential pharmacodynamic biomarkers for anti-mitotic cancer chemotherapy.
Collapse
Affiliation(s)
- Nurhan Özlü
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey Proteomics Center at Children's Hospital Boston, Boston, MA, USA Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Mohammad H Qureshi
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Yusuke Toyoda
- Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Bernhard Y Renard
- Research Group Bioinformatics (NG 4), Robert Koch-Institute, Berlin, Germany
| | - Gürkan Mollaoglu
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Nazlı E Özkan
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Selda Bulbul
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Ina Poser
- Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Wiebke Timm
- Proteomics Center at Children's Hospital Boston, Boston, MA, USA
| | - Anthony A Hyman
- Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Judith A Steen
- Proteomics Center at Children's Hospital Boston, Boston, MA, USA Department of Neurobiology, Harvard Medical School and Children's Hospital Boston, Boston, MA, USA
| |
Collapse
|
125
|
Carvalho CA, Moreira S, Ventura G, Sunkel CE, Morais-de-Sá E. Aurora A triggers Lgl cortical release during symmetric division to control planar spindle orientation. Curr Biol 2014; 25:53-60. [PMID: 25484294 DOI: 10.1016/j.cub.2014.10.053] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/23/2014] [Accepted: 10/21/2014] [Indexed: 11/30/2022]
Abstract
Mitotic spindle orientation is essential to control cell-fate specification and epithelial architecture. The tumor suppressor Lgl localizes to the basolateral cortex of epithelial cells, where it acts together with Dlg and Scrib to organize apicobasal polarity. Dlg and Scrib also control planar spindle orientation, but how the organization of polarity complexes is adjusted to control symmetric division is largely unknown. Here, we show that the Dlg complex is remodeled during Drosophila follicular epithelium cell division, when Lgl is released to the cytoplasm. Lgl redistribution during epithelial mitosis is reminiscent of asymmetric cell division, where it is proposed that Aurora A promotes aPKC activation to control the localization of Lgl and cell-fate determinants. We show that Aurora A controls Lgl localization directly, triggering its cortical release at early prophase in both epithelial and S2 cells. This relies on double phosphorylation within the putative aPKC phosphorylation site, which is required and sufficient for Lgl cortical release during mitosis and can be achieved by a combination of aPKC and Aurora A activities. Cortical retention of Lgl disrupts planar spindle orientation, but only when Lgl mutants that can bind Dlg are expressed. Hence, our work reveals that Lgl mitotic cortical release is not specifically linked to the asymmetric segregation of fate determinants, and we propose that Aurora A activation breaks the Dlg/Lgl interaction to allow planar spindle orientation during symmetric division via the Pins (LGN)/Dlg pathway.
Collapse
Affiliation(s)
- Cátia A Carvalho
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
| | - Sofia Moreira
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
| | - Guilherme Ventura
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
| | - Cláudio E Sunkel
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Eurico Morais-de-Sá
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
| |
Collapse
|
126
|
Marchesi S, Montani F, Deflorian G, D'Antuono R, Cuomo A, Bologna S, Mazzoccoli C, Bonaldi T, Di Fiore PP, Nicassio F. DEPDC1B coordinates de-adhesion events and cell-cycle progression at mitosis. Dev Cell 2014; 31:420-33. [PMID: 25458010 PMCID: PMC4250264 DOI: 10.1016/j.devcel.2014.09.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 08/05/2014] [Accepted: 09/15/2014] [Indexed: 11/25/2022]
Abstract
Cells entering mitosis become rounded, lose attachment to the substrate, and increase their cortical rigidity. Pivotal to these events is the dismantling of focal adhesions (FAs). How mitotic reshaping is linked to commitment to divide is unclear. Here, we show that DEPDC1B, a protein that accumulates in G2, coordinates de-adhesion events and cell-cycle progression at mitosis. DEPDC1B functions as an inhibitor of a RhoA-based signaling complex, which assembles on the FA-associated protein tyrosine phosphatase, receptor type, F (PTPRF) and mediates the integrity of FAs. By competing with RhoA for the interaction with PTPRF, DEPDC1B promotes the dismantling of FAs, which is necessary for the morphological changes preceding mitosis. The circuitry is relevant in whole organisms, as shown by the control exerted by the DEPDC1B/RhoA/PTPRF axis on mitotic dynamics during zebrafish development. Our results uncover an adhesion-dependent signaling mechanism that coordinates adhesion events with the control of cell-cycle progression. DEPDC1B is a cell-cycle gene involved in the transition from G2 phase to mitosis Persistent adhesion at G2 phase delays CycB/CDK1 activation and G2/M transition DEPDC1B controls RhoA/ROCK-dependent adhesion dynamics at G2 phase DEPDC1B inhibits RhoA activation by displacing it from the PTPRF/GEF-H1 complex
Collapse
Affiliation(s)
- Stefano Marchesi
- Istituto Europeo di Oncologia (IEO), 20141 Milan, Italy; Fondazione IFOM-Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy; Center for Genomic Science of IIT@SEMM, Istituto Italiano di Tecnologia (IIT), 20139 Milan, Italy
| | | | - Gianluca Deflorian
- Fondazione IFOM-Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy
| | - Rocco D'Antuono
- Fondazione IFOM-Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy
| | | | - Serena Bologna
- Fondazione IFOM-Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy
| | - Carmela Mazzoccoli
- Laboratory of Preclinical and Translational Research, IRCCS, Centro di Riferimento Oncologico della Basilicata, 85028 Rionero in Vulture (PZ), Italy
| | | | - Pier Paolo Di Fiore
- Istituto Europeo di Oncologia (IEO), 20141 Milan, Italy; Fondazione IFOM-Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy; Dipartimento di Scienze della Salute, Università degli Studi di Milano, 20142 Milan, Italy.
| | - Francesco Nicassio
- Istituto Europeo di Oncologia (IEO), 20141 Milan, Italy; Fondazione IFOM-Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy; Center for Genomic Science of IIT@SEMM, Istituto Italiano di Tecnologia (IIT), 20139 Milan, Italy.
| |
Collapse
|
127
|
Phosphoinositides: Lipids with informative heads and mastermind functions in cell division. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:832-43. [PMID: 25449648 DOI: 10.1016/j.bbalip.2014.10.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/21/2014] [Accepted: 10/28/2014] [Indexed: 01/22/2023]
Abstract
Phosphoinositides are low abundant but essential phospholipids in eukaryotic cells and refer to phosphatidylinositol and its seven polyphospho-derivatives. In this review, we summarize our current knowledge on phosphoinositides in multiple aspects of cell division in animal cells, including mitotic cell rounding, longitudinal cell elongation, cytokinesis furrow ingression, intercellular bridge abscission and post-cytokinesis events. PtdIns(4,5)P₂production plays critical roles in spindle orientation, mitotic cell shape and bridge stability after furrow ingression by recruiting force generator complexes and numerous cytoskeleton binding proteins. Later, PtdIns(4,5)P₂hydrolysis and PtdIns3P production are essential for normal cytokinesis abscission. Finally, emerging functions of PtdIns3P and likely PtdIns(4,5)P₂have recently been reported for midbody remnant clearance after abscission. We describe how the multiple functions of phosphoinositides in cell division reflect their distinct roles in local recruitment of protein complexes, membrane traffic and cytoskeleton remodeling. This article is part of a Special Issue entitled Phosphoinositides.
Collapse
|
128
|
Rohn JL, Patel JV, Neumann B, Bulkescher J, Mchedlishvili N, McMullan RC, Quintero OA, Ellenberg J, Baum B. Myo19 ensures symmetric partitioning of mitochondria and coupling of mitochondrial segregation to cell division. Curr Biol 2014; 24:2598-605. [PMID: 25447992 PMCID: PMC4228054 DOI: 10.1016/j.cub.2014.09.045] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/24/2014] [Accepted: 09/12/2014] [Indexed: 12/25/2022]
Abstract
During animal cell division, an actin-based ring cleaves the cell into two. Problems with this process can cause chromosome missegregation and defects in cytoplasmic inheritance and the partitioning of organelles, which in turn are associated with human diseases [1, 2, 3]. Although much is known about how chromosome segregation is coupled to cell division, the way organelles coordinate their inheritance during partitioning to daughter cells is less well understood. Here, using a high-content live-imaging small interfering RNA screen, we identify Myosin-XIX (Myo19) as a novel regulator of cell division. Previously, this actin-based motor was shown to control the interphase movement of mitochondria [4]. Our analysis shows that Myo19 is indeed localized to mitochondria and that its silencing leads to defects in the distribution of mitochondria within cells and in mitochondrial partitioning at division. Furthermore, many Myo19 RNAi cells undergo stochastic division failure—a phenotype that can be mimicked using a treatment that blocks mitochondrial fission and rescued by decreasing mitochondrial fusion, implying that mitochondria can physically interfere with cytokinesis. Strikingly, using live imaging we also observe the inappropriate movement of mitochondria to the poles of spindles in cells depleted for Myo19 as they enter anaphase. Since this phenocopies the results of an acute loss of actin filaments in anaphase, these data support a model whereby the Myo19 actin-based motor helps to control mitochondrial movement to ensure their faithful segregation during division. The presence of DNA within mitochondria makes their inheritance an especially important aspect of symmetrical cell division. RNAi screen identifies Myo19 as novel regulator of cell division Myo19 ensures fair mitochondrial inheritance at division Division requires coupled mitochondrial segregation and cytokinesis
Collapse
Affiliation(s)
- Jennifer L Rohn
- Centre for Clinical Science and Technology, Division of Medicine, University College London, Wolfson House, London NW1 2HE, UK.
| | - Jigna V Patel
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Beate Neumann
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jutta Bulkescher
- Novo Nordisk Foundation Center for Protein Research, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Nunu Mchedlishvili
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Rachel C McMullan
- Department of Biology, University of Richmond, Richmond, VA 23173, USA
| | - Omar A Quintero
- Department of Biology, University of Richmond, Richmond, VA 23173, USA
| | - Jan Ellenberg
- Department of Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
| |
Collapse
|
129
|
Zuo Y, Oh W, Frost JA. Controlling the switches: Rho GTPase regulation during animal cell mitosis. Cell Signal 2014; 26:2998-3006. [PMID: 25286227 DOI: 10.1016/j.cellsig.2014.09.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/23/2014] [Indexed: 11/29/2022]
Abstract
Animal cell division is a fundamental process that requires complex changes in cytoskeletal organization and function. Aberrant cell division often has disastrous consequences for the cell and can lead to cell senescence, neoplastic transformation or death. As important regulators of the actin cytoskeleton, Rho GTPases play major roles in regulating many aspects of mitosis and cytokinesis. These include centrosome duplication and separation, generation of cortical rigidity, microtubule-kinetochore stabilization, cleavage furrow formation, contractile ring formation and constriction, and abscission. The ability of Rho proteins to function as regulators of cell division depends on their ability to cycle between their active, GTP-bound and inactive, GDP-bound states. However, Rho proteins are inherently inefficient at fulfilling this cycle and require the actions of regulatory proteins that enhance GTP binding (RhoGEFs), stimulate GTPase activity (RhoGAPs), and sequester inactive Rho proteins in the cytosol (RhoGDIs). The roles of these regulatory proteins in controlling cell division are an area of active investigation. In this review we will delineate the current state of knowledge of how specific RhoGEFs, RhoGAPs and RhoGDIs control mitosis and cytokinesis, and highlight the mechanisms by which their functions are controlled.
Collapse
Affiliation(s)
- Yan Zuo
- University of Texas Health Science Center at Houston, Department of Integrative Biology and Pharmacology, 6431 Fannin St., Houston, TX 77030, United States
| | - Wonkyung Oh
- University of Texas Health Science Center at Houston, Department of Integrative Biology and Pharmacology, 6431 Fannin St., Houston, TX 77030, United States
| | - Jeffrey A Frost
- University of Texas Health Science Center at Houston, Department of Integrative Biology and Pharmacology, 6431 Fannin St., Houston, TX 77030, United States.
| |
Collapse
|
130
|
Park JH, Shin YJ, Riew TR, Lee MY. The indolinone MAZ51 induces cell rounding and G2/M cell cycle arrest in glioma cells without the inhibition of VEGFR-3 phosphorylation: involvement of the RhoA and Akt/GSK3β signaling pathways. PLoS One 2014; 9:e109055. [PMID: 25268128 PMCID: PMC4182637 DOI: 10.1371/journal.pone.0109055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 09/02/2014] [Indexed: 12/20/2022] Open
Abstract
MAZ51 is an indolinone-based molecule originally synthesized as a selective inhibitor of vascular endothelial growth factor receptor (VEGFR)-3 tyrosine kinase. This study shows that exposure of two glioma cell lines, rat C6 and human U251MG, to MAZ51 caused dramatic shape changes, including the retraction of cellular protrusions and cell rounding. These changes were caused by the clustering and aggregation of actin filaments and microtubules. MAZ51 also induced G2/M phase cell cycle arrest. This led to an inhibition of cellular proliferation, without triggering significant cell death. These alterations induced by MAZ51 occurred with similar dose- and time-dependent patterns. Treatment of glioma cells with MAZ51 resulted in increased levels of phosphorylated GSK3β through the activation of Akt, as well as increased levels of active RhoA. Interestingly, MAZ51 did not affect the morphology and cell cycle patterns of rat primary cortical astrocytes, suggesting it selectively targeted transformed cells. Immunoprecipitation–western blot analyses indicated that MAZ51 did not decrease, but rather increased, tyrosine phosphorylation of VEGFR-3. To confirm this unanticipated result, several additional experiments were conducted. Enhancing VEGFR-3 phosphorylation by treatment of glioma cells with VEGF-C affected neither cytoskeleton arrangements nor cell cycle patterns. In addition, the knockdown of VEGFR-3 in glioma cells did not cause morphological or cytoskeletal alterations. Furthermore, treatment of VEGFR-3-silenced cells with MAZ51 caused the same alterations of cell shape and cytoskeletal arrangements as that observed in control cells. These data indicate that MAZ51 causes cytoskeletal alterations and G2/M cell cycle arrest in glioma cells. These effects are mediated through phosphorylation of Akt/GSK3β and activation of RhoA. The anti-proliferative activity of MAZ51 does not require the inhibition of VEGFR-3 phosphorylation, suggesting that it is a potential candidate for further clinical investigation for treatment of gliomas, although the precise mechanism(s) underlying its effects remain to be determined.
Collapse
Affiliation(s)
- Joo-Hee Park
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yoo-Jin Shin
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
- * E-mail:
| |
Collapse
|
131
|
Fischer-Friedrich E, Hyman AA, Jülicher F, Müller DJ, Helenius J. Quantification of surface tension and internal pressure generated by single mitotic cells. Sci Rep 2014; 4:6213. [PMID: 25169063 PMCID: PMC4148660 DOI: 10.1038/srep06213] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/05/2014] [Indexed: 01/11/2023] Open
Abstract
During mitosis, adherent cells round up, by increasing the tension of the contractile actomyosin cortex while increasing the internal hydrostatic pressure. In the simple scenario of a liquid cell interior, the surface tension is related to the local curvature and the hydrostatic pressure difference by Laplace's law. However, verification of this scenario for cells requires accurate measurements of cell shape. Here, we use wedged micro-cantilevers to uniaxially confine single cells and determine confinement forces while concurrently determining cell shape using confocal microscopy. We fit experimentally measured confined cell shapes to shapes obeying Laplace's law with uniform surface tension and find quantitative agreement. Geometrical parameters derived from fitting the cell shape, and the measured force were used to calculate hydrostatic pressure excess and surface tension of cells. We find that HeLa cells increase their internal hydrostatic pressure excess and surface tension from ≈ 40 Pa and 0.2 mNm(-1) during interphase to ≈ 400 Pa and 1.6 mNm(-1) during metaphase. The method introduced provides a means to determine internal pressure excess and surface tension of rounded cells accurately and with minimal cellular perturbation, and should be applicable to characterize the mechanical properties of various cellular systems.
Collapse
Affiliation(s)
- Elisabeth Fischer-Friedrich
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Anthony A. Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - Daniel J. Müller
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zürich, Mattenstr. 26, 4058 Basel, Switzerland
| | - Jonne Helenius
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zürich, Mattenstr. 26, 4058 Basel, Switzerland
| |
Collapse
|
132
|
Baum B, Sedwick C. Buzz Baum: The art of cell shape. J Cell Biol 2014; 206:332-3. [PMID: 25092653 PMCID: PMC4121982 DOI: 10.1083/jcb.2063pi] [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] [Indexed: 11/22/2022] Open
Abstract
Baum studies how cell shape affects tissue development, homeostasis, and cancer.
Collapse
|
133
|
Chircop M. Rho GTPases as regulators of mitosis and cytokinesis in mammalian cells. Small GTPases 2014; 5:29770. [PMID: 24988197 DOI: 10.4161/sgtp.29770] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rho GTPases regulate a diverse range of cellular functions primarily through their ability to modulate microtubule dynamics and the actin-myosin cytoskeleton. Both of these cytoskeletal structures are crucial for a mitotic cell division. Specifically, their assembly and disassembly is tightly regulated in a temporal manner to ensure that each mitotic stage occurs in the correct sequential order and not prematurely until the previous stage is completed. Thus, it is not surprising that the Rho GTPases, RhoA, and Cdc42, have reported roles in several stages of mitosis: cell cortex stiffening during cell rounding, mitotic spindle formation, and bi-orient attachment of the spindle microtubules to the kinetochore and during cytokinesis play multiple roles in establishing the division plane, assembly, and activation of the contractile ring, membrane ingression, and abscission. Here, I review the molecular mechanisms regulating the spatial and temporal activation of RhoA and Cdc42 during mitosis, and how this is critical for mitotic progression and completion.
Collapse
Affiliation(s)
- Megan Chircop
- Children's Medical Research Institute; The University of Sydney; Westmead, Australia
| |
Collapse
|
134
|
Abstract
The final stage of cell division (mitosis), involves the compaction of the duplicated genome into chromatid pairs. Each pair is captured by microtubules emanating from opposite spindle poles, aligned at the metaphase plate, and then faithfully segregated to form two identical daughter cells. Chromatids that are not correctly attached to the spindle are detected by the constitutively active spindle assembly checkpoint (SAC). Any stress that prevents correct bipolar spindle attachment, blocks the satisfaction of the SAC, and induces a prolonged mitotic arrest, providing the cell time to obtain attachment and complete segregation correctly. Unfortunately, during mitosis repairing damage is not generally possible due to the compaction of DNA into chromosomes, and subsequent suppression of gene transcription and translation. Therefore, in the presence of significant damage cell death is instigated to ensure that genomic stability is maintained. While most stresses lead to an arrest in mitosis, some promote premature mitotic exit, allowing cells to bypass mitotic cell death. This mini-review will focus on the effects and outcomes that common stresses have on mitosis, and how this impacts on the efficacy of mitotic chemotherapies.
Collapse
Affiliation(s)
- Andrew Burgess
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research , Sydney, NSW , Australia ; St. Vincent's Clinical School, Faculty of Medicine, UNSW Australia , Sydney, NSW , Australia
| | - Mina Rasouli
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research , Sydney, NSW , Australia
| | - Samuel Rogers
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research , Sydney, NSW , Australia
| |
Collapse
|
135
|
Guillemot L, Guerrera D, Spadaro D, Tapia R, Jond L, Citi S. MgcRacGAP interacts with cingulin and paracingulin to regulate Rac1 activation and development of the tight junction barrier during epithelial junction assembly. Mol Biol Cell 2014; 25:1995-2005. [PMID: 24807907 PMCID: PMC4072573 DOI: 10.1091/mbc.e13-11-0680] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The Rac1 inhibitor MgcRacGAP regulates Rac1 activation and TJ barrier development during junction assembly in epithelial cells. CGN and CGNL1 recruit MgcRacGAP to the TJ and interact with MgcRacGAP. The regulation of Rho-family GTPases is crucial to direct the formation of cell–cell junctions and tissue barriers. Cingulin (CGN) and paracingulin (CGNL1) control RhoA activation in epithelial cells by interacting with RhoA guanidine exchange factors. CGNL1 depletion also inhibits Rac1 activation during junction assembly. Here we show that, unexpectedly, Madin–Darby canine kidney epithelial cells depleted of both CGN and CGNL1 (double-KD cells) display normal Rac1 activation and tight junction (TJ) formation, despite decreased junctional recruitment of the Rac1 activator Tiam1. The expression of the Rac1 inhibitor MgcRacGAP is decreased in double-KD cells, and the barrier development and Rac1 activation phenotypes are rescued by exogenous expression of MgcRacGAP. MgcRacGAP colocalizes with CGN and CGNL1 at TJs and forms a complex and interacts directly in vitro with CGN and CGNL1. Depletion of either CGN or CGNL1 in epithelial cells results in decreased junctional localization of MgcRacGAP but not of ECT2, a centralspindlin-interacting Rho GEF. These results provide new insight into coordination of Rho-family GTPase activities at junctions, since apical accumulation of CGN and CGNL1 at TJs during junction maturation provides a mechanism to spatially restrict down-regulation of Rac1 activation through the recruitment of MgcRacGAP.
Collapse
Affiliation(s)
- Laurent Guillemot
- Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland
| | - Diego Guerrera
- Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland
| | - Domenica Spadaro
- Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland
| | - Rocio Tapia
- Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland
| | - Lionel Jond
- Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland
| | - Sandra Citi
- Department of Molecular Biology, University of Geneva, CH-1211 Geneva, SwitzerlandDepartment of Cell Biology, University of Geneva, CH-1211 Geneva, SwitzerlandInstitute of Genetics and Genomics in Geneva, University of Geneva, CH-1211 Geneva, Switzerland
| |
Collapse
|
136
|
Sfregola M. Centralspindlin is required for thorax development during Drosophila metamorphosis. Genesis 2014; 52:387-98. [PMID: 24700509 DOI: 10.1002/dvg.22777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 03/26/2014] [Accepted: 03/31/2014] [Indexed: 01/23/2023]
Abstract
Epithelial morphogenesis is an essential process in all metazoans during both normal development and pathological processes such as wound healing. The coordinated regulation of cell shape, cell size, and cell adhesion during the migration of epithelial sheets ultimately gives rise to the diversity of body plans among different organisms as well as the diversity of cellular structures and tissues within an organism. Metamorphosis of the Drosophila pupa is an excellent system to study these transformative events. During pupal development, the cells of the wing imaginal discs migrate dorsally and fuse to form the adult thorax. Here I show centralspindlin, a protein complex well known for its role in cytokinesis, is essential for migration of wing disc cells and proper thorax closure. I show the subcellular localization of centralspindlin is important for its function in thorax development. This study demonstrates the emerging role of centralspindlin in regulating cell migration and cell adhesion in addition to its previously known function during cytokinesis.
Collapse
Affiliation(s)
- Michael Sfregola
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado
| |
Collapse
|
137
|
|
138
|
Lancaster OM, Baum B. Shaping up to divide: coordinating actin and microtubule cytoskeletal remodelling during mitosis. Semin Cell Dev Biol 2014; 34:109-15. [PMID: 24607328 DOI: 10.1016/j.semcdb.2014.02.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 02/26/2014] [Indexed: 10/25/2022]
Abstract
Cell division requires the wholesale reorganization of cell architecture. At the same time as the microtubule network is remodelled to generate a bipolar spindle, animal cells entering mitosis replace their interphase actin cytoskeleton with a contractile mitotic actomyosin cortex that is tightly coupled to the plasma membrane--driving mitotic cell rounding. Here, we consider how these two processes are coordinated to couple chromosome segregation and cell division. In doing so we explore the relative roles of cell shape and the actin cortex in spindle morphogenesis, orientation and positioning.
Collapse
Affiliation(s)
- Oscar M Lancaster
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| |
Collapse
|
139
|
Kaur S, Fielding AB, Gassner G, Carter NJ, Royle SJ. An unmet actin requirement explains the mitotic inhibition of clathrin-mediated endocytosis. eLife 2014; 3:e00829. [PMID: 24550251 PMCID: PMC3924242 DOI: 10.7554/elife.00829] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Clathrin-mediated endocytosis (CME) is the major internalisation route for many different receptor types in mammalian cells. CME is shut down during early mitosis, but the mechanism of this inhibition is unclear. In this study, we show that the mitotic shutdown is due to an unmet requirement for actin in CME. In mitotic cells, membrane tension is increased and this invokes a requirement for the actin cytoskeleton to assist the CME machinery to overcome the increased load. However, the actin cytoskeleton is engaged in the formation of a rigid cortex in mitotic cells and is therefore unavailable for deployment. We demonstrate that CME can be ‘restarted’ in mitotic cells despite high membrane tension, by allowing actin to engage in endocytosis. Mitotic phosphorylation of endocytic proteins is maintained in mitotic cells with restored CME, indicating that direct phosphorylation of the CME machinery does not account for shutdown. DOI:http://dx.doi.org/10.7554/eLife.00829.001 The plasma membrane that surrounds a cell acts as a protective barrier that regulates what can enter or exit the cell. However, large molecules and other ‘cargo’ can get into a cell in a variety of ways. One of these routes—known as clathrin-mediated endocytosis—involves a receptor on the outside of the membrane grabbing hold of the cargo while a protein called clathrin forms a ‘pit’ beneath the receptor. This pit becomes deeper and deeper until the cargo is completely surrounded by clathrin-lined membrane and is brought inside the cell. This process has been studied over the past 50 years, and it is known that clathrin-mediated endocytosis is turned off when a cell begins to divide to produce new cells, and then turned back on when cell division has come to an end. However, there are competing theories as to exactly why this process stops when cell division starts. Now, Kaur et al. have investigated these theories by looking at the role that another protein, called actin, plays in turning off clathrin-mediated endocytosis. Actin is a molecule that forms a sort of scaffolding within the cell (called the cytoskeleton), and it also guides the movement of molecules and larger structures within the cell. Further, when the cell membrane is being stretched, the actin cytoskeleton can assist the clathrin-mediated endocytosis machinery to pull cargo into the cell. So why doesn’t actin help with endocytosis during cell division? The answer, Kaur et al. suggest, is that all the actin in the cell is needed by the cytoskeleton during cell division, so there is no actin available to perform other tasks such as clathrin-mediated endocytosis. Further experiments demonstrated that this form of endocytosis can be ‘restarted’ in dividing cells by treating the cells in a way that frees up some additional actin. The work of Kaur et al. also ruled out the theory that chemical changes to the endocytosis machinery disabled it during cell division. These findings have implications for the delivery of drugs, via endocytosis, to the rapidly dividing cells that are involved in diseases such as cancer. DOI:http://dx.doi.org/10.7554/eLife.00829.002
Collapse
Affiliation(s)
- Satdip Kaur
- Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | | | | | | |
Collapse
|
140
|
Kim H, Guo F, Brahma S, Xing Y, Burkard ME. Centralspindlin assembly and 2 phosphorylations on MgcRacGAP by Polo-like kinase 1 initiate Ect2 binding in early cytokinesis. Cell Cycle 2014; 13:2952-61. [PMID: 25486482 PMCID: PMC4614826 DOI: 10.4161/15384101.2014.947201] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 01/08/2023] Open
Abstract
Cytokinesis is the final step of cell division which partitions genetic and cytosolic content into daughter cells. Failed cytokinesis causes polyploidy, genetic instability, and cancer. Kinases use phosphorylation to regulate the timing and location of the cytokinetic furrow. Polo-like kinase 1 (Plk1) is an essential mitotic kinase that triggers cytokinesis by phosphorylating MgcRacGAP to create a docking site for Ect2 at the central spindle. Ect2 binds to MgcRacGAP via its N-terminal BRCT domain (BRCA1 C-terminal), which docks at specific phosphorylated residues. Here we investigate the minimal Plk1-dependent phosphorylation sites required for cytokinesis onset. We demonstrate that phosphorylation of the major MgcRacGAP site, S157, is necessary but not sufficient to bind the Ect2 BRCT domain. Phosphorylation of an additional residue on MgcRacGAP at S164 is also required to elicit efficient binding. Surprisingly, BRCT binding additionally requires MKLP1 and its cognate interacting N-terminal domain of MgcRacGAP. Our findings indicate that central spindle assembly and 2 Plk1-dependent phosphorylations are required to establish efficient binding of the Ect2 BRCT in early cytokinesis. We propose that these requirements establish a high threshold to restrain premature or ectopic cytokinesis.
Collapse
Affiliation(s)
- Hyunjung Kim
- Hematology/Oncology Division; Department of Medicine; University of Wisconsin Carbone Cancer Center; Madison, WI USA
| | - Feng Guo
- McArdle Laboratory; Department of Oncology; School of Medicine and Public Health; University of Wisconsin; Madison, WI USA
- Current Affiliation: School of Medicine; Stanford University; Stanford, CA USA
| | - Sarang Brahma
- Hematology/Oncology Division; Department of Medicine; University of Wisconsin Carbone Cancer Center; Madison, WI USA
| | - Yongna Xing
- McArdle Laboratory; Department of Oncology; School of Medicine and Public Health; University of Wisconsin; Madison, WI USA
| | - Mark E Burkard
- Hematology/Oncology Division; Department of Medicine; University of Wisconsin Carbone Cancer Center; Madison, WI USA
| |
Collapse
|
141
|
Fortin Ensign SP, Mathews IT, Symons MH, Berens ME, Tran NL. Implications of Rho GTPase Signaling in Glioma Cell Invasion and Tumor Progression. Front Oncol 2013; 3:241. [PMID: 24109588 PMCID: PMC3790103 DOI: 10.3389/fonc.2013.00241] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 09/02/2013] [Indexed: 01/21/2023] Open
Abstract
Glioblastoma (GB) is the most malignant of primary adult brain tumors, characterized by a highly locally invasive cell population, as well as abundant proliferative cells, neoangiogenesis, and necrosis. Clinical intervention with chemotherapy or radiation may either promote or establish an environment for manifestation of invasive behavior. Understanding the molecular drivers of invasion in the context of glioma progression may be insightful in directing new treatments for patients with GB. Here, we review current knowledge on Rho family GTPases, their aberrant regulation in GB, and their effect on GB cell invasion and tumor progression. Rho GTPases are modulators of cell migration through effects on actin cytoskeleton rearrangement; in non-neoplastic tissue, expression and activation of Rho GTPases are normally under tight regulation. In GB, Rho GTPases are deregulated, often via hyperactivity or overexpression of their activators, Rho GEFs. Downstream effectors of Rho GTPases have been shown to promote invasiveness and, importantly, glioma cell survival. The study of aberrant Rho GTPase signaling in GB is thus an important investigation of cell invasion as well as treatment resistance and disease progression.
Collapse
Affiliation(s)
- Shannon Patricia Fortin Ensign
- Cancer and Cell Biology Division, Translational Genomics Research Institute , Phoenix, AZ , USA ; Cancer Biology Graduate Interdisciplinary Program, University of Arizona , Tucson, AZ , USA
| | | | | | | | | |
Collapse
|
142
|
Zanin E, Desai A, Poser I, Toyoda Y, Andree C, Moebius C, Bickle M, Conradt B, Piekny A, Oegema K. A conserved RhoGAP limits M phase contractility and coordinates with microtubule asters to confine RhoA during cytokinesis. Dev Cell 2013; 26:496-510. [PMID: 24012485 DOI: 10.1016/j.devcel.2013.08.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 05/22/2013] [Accepted: 08/07/2013] [Indexed: 12/27/2022]
Abstract
During animal cell cytokinesis, the spindle directs contractile ring assembly by activating RhoA in a narrow equatorial zone. Rapid GTPase activating protein (GAP)-mediated inactivation (RhoA flux) is proposed to limit RhoA zone dimensions. Testing the significance of RhoA flux has been hampered by the fact that the GAP targeting RhoA is not known. Here, we identify M phase GAP (MP-GAP) as the primary GAP targeting RhoA during mitosis and cytokinesis. MP-GAP inhibition caused excessive RhoA activation in M phase, leading to the uncontrolled formation of large cortical protrusions and late cytokinesis failure. RhoA zone width was broadened by attenuation of the centrosomal asters but was not affected by MP-GAP inhibition alone. Simultaneous aster attenuation and MP-GAP inhibition led to RhoA accumulation around the entire cell periphery. These results identify the major GAP restraining RhoA during cell division and delineate the relative contributions of RhoA flux and centrosomal asters in controlling RhoA zone dimensions.
Collapse
Affiliation(s)
- Esther Zanin
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA; Center for Integrated Protein Science CIPSM, Department Biology II, Ludwig-Maximilians University, Munich, 82152 Planegg-Martinsried, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
143
|
Solinet S, Mahmud K, Stewman SF, Ben El Kadhi K, Decelle B, Talje L, Ma A, Kwok BH, Carreno S. The actin-binding ERM protein Moesin binds to and stabilizes microtubules at the cell cortex. J Cell Biol 2013; 202:251-60. [PMID: 23857773 PMCID: PMC3718980 DOI: 10.1083/jcb.201304052] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/07/2013] [Indexed: 01/15/2023] Open
Abstract
Ezrin, Radixin, and Moesin (ERM) proteins play important roles in many cellular processes including cell division. Recent studies have highlighted the implications of their metastatic potential in cancers. ERM's role in these processes is largely attributed to their ability to link actin filaments to the plasma membrane. In this paper, we show that the ERM protein Moesin directly binds to microtubules in vitro and stabilizes microtubules at the cell cortex in vivo. We identified two evolutionarily conserved residues in the FERM (4.1 protein and ERM) domains of ERMs that mediated the association with microtubules. This ERM-microtubule interaction was required for regulating spindle organization in metaphase and cell shape transformation after anaphase onset but was dispensable for bridging actin filaments to the metaphase cortex. These findings provide a molecular framework for understanding the complex functional interplay between the microtubule and actin cytoskeletons mediated by ERM proteins in mitosis and have broad implications in both physiological and pathological processes that require ERMs.
Collapse
Affiliation(s)
- Sara Solinet
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Kazi Mahmud
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Shannon F. Stewman
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL 60607
| | - Khaled Ben El Kadhi
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Barbara Decelle
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Lama Talje
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Ao Ma
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL 60607
| | - Benjamin H. Kwok
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
- Département de médecine and Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Sébastien Carreno
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
- Département de médecine and Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| |
Collapse
|
144
|
Mitotic rounding alters cell geometry to ensure efficient bipolar spindle formation. Dev Cell 2013; 25:270-83. [PMID: 23623611 DOI: 10.1016/j.devcel.2013.03.014] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 02/14/2013] [Accepted: 03/21/2013] [Indexed: 01/07/2023]
Abstract
Accurate animal cell division requires precise coordination of changes in the structure of the microtubule-based spindle and the actin-based cell cortex. Here, we use a series of perturbation experiments to dissect the relative roles of actin, cortical mechanics, and cell shape in spindle formation. We find that, whereas the actin cortex is largely dispensable for rounding and timely mitotic progression in isolated cells, it is needed to drive rounding to enable unperturbed spindle morphogenesis under conditions of confinement. Using different methods to limit mitotic cell height, we show that a failure to round up causes defects in spindle assembly, pole splitting, and a delay in mitotic progression. These defects can be rescued by increasing microtubule lengths and therefore appear to be a direct consequence of the limited reach of mitotic centrosome-nucleated microtubules. These findings help to explain why most animal cells round up as they enter mitosis.
Collapse
|
145
|
Guillot C, Lecuit T. Adhesion Disengagement Uncouples Intrinsic and Extrinsic Forces to Drive Cytokinesis in Epithelial Tissues. Dev Cell 2013; 24:227-41. [DOI: 10.1016/j.devcel.2013.01.010] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/30/2012] [Accepted: 01/10/2013] [Indexed: 01/17/2023]
|
146
|
Werner A, Disanza A, Reifenberger N, Habeck G, Becker J, Calabrese M, Urlaub H, Lorenz H, Schulman B, Scita G, Melchior F. SCFFbxw5 mediates transient degradation of actin remodeller Eps8 to allow proper mitotic progression. Nat Cell Biol 2013; 15:179-88. [PMID: 23314863 DOI: 10.1038/ncb2661] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/26/2012] [Indexed: 12/22/2022]
Abstract
Eps8, a bi-functional actin cytoskeleton remodeller, is a positive regulator of cell proliferation and motility. Here, we describe an unrecognized mechanism regulating Eps8 that is required for proper mitotic progression: whereas Eps8 is stable in G1 and S phase, its half-life drops sharply in G2. This requires G2-specific proteasomal degradation mediated by the ubiquitin E3 ligase SCF(Fbxw5). Consistent with a short window of degradation, Eps8 disappears from the cell cortex early in mitosis, but reappears at the midzone of dividing cells. Failure to reduce Eps8 levels in G2 prolongs its localization at the cell cortex and markedly delays cell rounding and prometaphase duration. However, during late stages of mitosis and cytokinesis, Eps8 capping activity is required to prevent membrane blebbing and cell-shape deformations. Our findings identify SCF(Fbxw5)-driven fluctuation of Eps8 levels as an important mechanism that contributes to cell-shape changes during entry into-and exit from-mitosis.
Collapse
Affiliation(s)
- Achim Werner
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
147
|
Matthews HK, Baum B. The metastatic cancer cell cortex: An adaptation to enhance robust cell division in novel environments? Bioessays 2012; 34:1017-20. [DOI: 10.1002/bies.201200109] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|