51
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Hoeller O, Bolourani P, Clark J, Stephens LR, Hawkins PT, Weiner OD, Weeks G, Kay RR. Two distinct functions for PI3-kinases in macropinocytosis. J Cell Sci 2013; 126:4296-307. [PMID: 23843627 DOI: 10.1242/jcs.134015] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Class-1 PI3-kinases are major regulators of the actin cytoskeleton, whose precise contributions to chemotaxis, phagocytosis and macropinocytosis remain unresolved. We used systematic genetic ablation to examine this question in growing Dictyostelium cells. Mass spectroscopy shows that a quintuple mutant lacking the entire genomic complement of class-1 PI3-kinases retains only 10% of wild-type PtdIns(3,4,5)P3 levels. Chemotaxis to folate and phagocytosis of bacteria proceed normally in the quintuple mutant but macropinocytosis is abolished. In this context PI3-kinases show specialized functions, only one of which is directly linked to gross PtdIns(3,4,5)P3 levels: macropinosomes originate in patches of PtdIns(3,4,5)P3, with associated F-actin-rich ruffles, both of which depend on PI3-kinase 1/2 (PI3K1/2) but not PI3K4, whereas conversion of ruffles into vesicles requires PI3K4. A biosensor derived from the Ras-binding domain of PI3K1 suggests that Ras is activated throughout vesicle formation. Binding assays show that RasG and RasS interact most strongly with PI3K1/2 and PI3K4, and single mutants of either Ras have severe macropinocytosis defects. Thus, the fundamental function of PI3-kinases in growing Dictyostelium cells is in macropinocytosis where they have two distinct functions, supported by at least two separate Ras proteins.
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Affiliation(s)
- Oliver Hoeller
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
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52
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Bravo-Cordero JJ, Sharma VP, Roh-Johnson M, Chen X, Eddy R, Condeelis J, Hodgson L. Spatial regulation of RhoC activity defines protrusion formation in migrating cells. J Cell Sci 2013; 126:3356-69. [PMID: 23704350 DOI: 10.1242/jcs.123547] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Protrusion formation is the first step that precedes cell movement of motile cells. Spatial control of actin polymerization is necessary to achieve directional protrusion during cell migration. Here we show that the spatial coordinators p190RhoGEF and p190RhoGAP regulate actin polymerization during leading edge protrusions by regulating the actin barbed end distribution and amplitude. The distribution of RhoC activity and proper balance of cofilin activation achieved by p190RhoGEF and p190RhoGAP determines the direction of final protrusive activity. These findings provide a new insight into the dynamic plasticity in the amplitude and distribution of barbed ends, which can be modulated by fine-tuning RhoC activity by upstream GEFs and GAPs for directed cell motility.
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Affiliation(s)
- Jose Javier Bravo-Cordero
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA.
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53
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Abstract
In the last five years, the zebrafish (Danio rerio) has rapidly gained popularity as a model system for studying leukocyte migration and trafficking in vivo. The optical clarity of zebrafish embryos, as well as the potential for genetic manipulation and the development of tools for live imaging, have provided new insight into how leukocytes migrate in response to directional cues in live animals. This Commentary discusses recent progress in our understanding of how leukocytes migrate in vivo, including the role of intracellular signaling through phosphatidylinositol 3-kinase (PI3K) in both random and directed migration. The importance of leukocyte reverse migration in the resolution of inflammation will also be discussed. Finally, we will highlight how zebrafish models have helped to provide new insight into leukocyte migration and the way in which migration is altered in disease.
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Affiliation(s)
- Qing Deng
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
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54
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Allena R. Cell migration with multiple pseudopodia: temporal and spatial sensing models. Bull Math Biol 2013; 75:288-316. [PMID: 23319383 DOI: 10.1007/s11538-012-9806-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 12/20/2012] [Indexed: 01/15/2023]
Abstract
Cell migration triggered by pseudopodia (or "false feet") is the most used method of locomotion. A 3D finite element model of a cell migrating over a 2D substrate is proposed, with a particular focus on the mechanical aspects of the biological phenomenon. The decomposition of the deformation gradient is used to reproduce the cyclic phases of protrusion and contraction of the cell, which are tightly synchronized with the adhesion forces at the back and at the front of the cell, respectively. First, a steady active deformation is considered to show the ability of the cell to simultaneously initiate multiple pseudopodia. Here, randomness is considered as a key aspect, which controls both the direction and the amplitude of the false feet. Second, the migration process is described through two different strategies: the temporal and the spatial sensing models. In the temporal model, the cell "sniffs" the surroundings by extending several pseudopodia and only the one that receives a positive input will become the new leading edge, while the others retract. In the spatial model instead, the cell senses the external sources at different spots of the membrane and only protrudes one pseudopod in the direction of the most attractive one.
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Affiliation(s)
- Rachele Allena
- Arts et Metiers ParisTech, LBM, 151 bd de l'hopital, 75013 Paris, France.
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55
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Runne C, Chen S. WD40-repeat proteins control the flow of Gβγ signaling for directional cell migration. Cell Adh Migr 2013; 7:214-8. [PMID: 23302952 DOI: 10.4161/cam.22940] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ability of cells to generate a highly polarized intracellular signal through G protein-coupled receptors (GPCRs) is essential for their migration toward chemoattractants. The Gβγ subunits of heterotrimeric G proteins play a critical role in transmitting chemotactic signals from GPCRs via the activation of diverse effectors, including PLCβ and PI3K, primarily at the leading edge of cells. Although Gβγ can directly activate many of these effectors through protein-protein interactions in vitro, it remains unclear how Gβγ spatially and temporally orchestrates the activation of these effectors in vivo. A yeast two-hybrid screen for Gβ interacting proteins identified two WD40-repeat domain containing proteins, RACK1 and WDR26, which are predicted to serve as scaffolding/adaptor proteins. Previous data indicates that RACK1 negatively regulates Gβγ-mediated leukocyte migration by inhibiting Gβγ-stimulated PLCβ and PI3K activities. In contrast, recently published work by Sun et al. indicates that WDR26 promotes leukocyte migration by enhancing Gβγ-mediated signal transduction. These findings reveal a novel mechanism regulating Gβγ signaling during chemotaxis, namely through the positive and negative regulation of WDR26 and RACK1 on Gβγ to promote and fine tune Gβγ-mediated effector activation, ultimately governing the ability of cells to polarize and migrate toward a chemoattractant gradient.
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Affiliation(s)
- Caitlin Runne
- Department of Pharmacology; Roy J. and Lucille A. Carver College of Medicine; University of Iowa; Iowa City, IA USA
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56
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Chan C, Billard M, Ramirez SA, Schmidl H, Monson E, Kepler TB. A model for migratory B cell oscillations from receptor down-regulation induced by external chemokine fields. Bull Math Biol 2013; 75:185-205. [PMID: 23296998 PMCID: PMC3547247 DOI: 10.1007/s11538-012-9799-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 11/15/2012] [Indexed: 01/28/2023]
Abstract
A long-standing paradigm in B cell immunology is that effective somatic hypermutation and affinity maturation require cycling between the dark zone and light zone of the germinal center. The cyclic re-entry hypothesis was first proposed based on considerations of the efficiency of affinity maturation using an ordinary differential equations model for B cell population dynamics. More recently, two-photon microscopy studies of B cell motility within lymph nodes in situ have revealed the complex migration patterns of B lymphocytes both in the preactivation follicle and post-activation germinal center. There is strong evidence that chemokines secreted by stromal cells and the regulation of cognate G-protein coupled receptors by these chemokines are necessary for the observed spatial cell distributions. For example, the distribution of B cells within the light and dark zones of the germinal center appears to be determined by the reciprocal interaction between the level of the CXCR4 and CXCR5 receptors and the spatial distribution of their respective chemokines CXCL12 and CXCL13. Computer simulations of individual-based models have been used to study the complex biophysical and mechanistic processes at the individual cell level, but such simulations can be challenging to parameterize and analyze. In contrast, ordinary differential equations are more tractable, but traditional compartment model formalizations ignore the spatial chemokine distribution that drives B cell redistribution. Motivated by the desire to understand the motility patterns observed in an individual-based simulation of B cell migration in the lymph node, we propose and analyze the dynamics of an ordinary differential equation model incorporating explicit chemokine spatial distributions. While there is experimental evidence that B cell migration patterns in the germinal center are driven by extrinsically regulated differentiation programs, the model shows, perhaps surprisingly, that feedback from receptor down-regulation induced by external chemokine fields can give rise to spontaneous interzonal and intrazonal oscillations in the absence of any extrinsic regulation. While the extent to which such simple feedback mechanisms contributes to B cell migration patterns in the germinal center is unknown, the model provides an alternative hypothesis for how complex B cell migration patterns might arise from very simple mechanisms.
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Affiliation(s)
- Cliburn Chan
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27705, USA.
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57
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DeFlorio R, Brett ME, Waszczak N, Apollinari E, Metodiev MV, Dubrovskyi O, Eddington D, Arkowitz RA, Stone DE. Gβ phosphorylation is critical for efficient chemotropism in yeast. J Cell Sci 2013; 126:2997-3009. [DOI: 10.1242/jcs.112797] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mating yeast cells interpret complex pheromone gradients and polarize their growth in the direction of the closest partner. Chemotropic growth depends on both the pheromone receptor and its associated G-protein. Upon activation by the receptor, Gα dissociates from Gβγ and Gβ is subsequently phosphorylated. Free Gβγ signals to the nucleus via a MAPK cascade and recruits Far1-Cdc24 to the incipient growth site. It is not clear how the cell establishes and stabilizes the axis of polarity, but this process is thought to require local signal amplification via the Gβγ-Far1-Cdc24 chemotropic complex, as well as communication between this complex and the activated receptor. Here we show that a mutant form of Gβ that cannot be phosphorylated confers defects in directional sensing and chemotropic growth. Our data suggest that phosphorylation of Gβ plays a role in localized signal amplification and in the dynamic communication between the receptor and the chemotropic complex, which underlie growth site selection and maintenance.
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58
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59
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Gericke A, Leslie NR, Lösche M, Ross AH. PtdIns(4,5)P2-mediated cell signaling: emerging principles and PTEN as a paradigm for regulatory mechanism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:85-104. [PMID: 23775692 DOI: 10.1007/978-94-007-6331-9_6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) is a relatively common anionic lipid that regulates cellular functions by multiple mechanisms. Hydrolysis of PtdIns(4,5)P2 by phospholipase C yields inositol trisphosphate and diacylglycerol. Phosphorylation by phosphoinositide 3-kinase yields PtdIns(3,4,5)P3, which is a potent signal for survival and proliferation. Also, PtdIns(4,5)P2 can bind directly to integral and peripheral membrane proteins. As an example of regulation by PtdIns(4,5)P2, we discuss phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in detail. PTEN is an important tumor suppressor and hydrolyzes PtdIns(3,4,5)P3. PtdIns(4,5)P2 enhances PTEN association with the plasma membrane and activates its phosphatase activity. This is a critical regulatory mechanism, but a detailed description of this process from a structural point of view is lacking. The disordered lipid bilayer environment hinders structural determinations of membrane-bound PTEN. A new method to analyze membrane-bound protein measures neutron reflectivity for proteins bound to tethered phospholipid membranes. These methods allow determination of the orientation and shape of membrane-bound proteins. In combination with molecular dynamics simulations, these studies will provide crucial structural information that can serve as a foundation for our understanding of PTEN regulation in normal and pathological processes.
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Affiliation(s)
- Arne Gericke
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA 01609, USA
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60
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Tan RZ, Ji N, Mentink RA, Korswagen HC, van Oudenaarden A. Deconvolving the roles of Wnt ligands and receptors in sensing and amplification. Mol Syst Biol 2013; 9:631. [PMID: 23295860 PMCID: PMC3564265 DOI: 10.1038/msb.2012.64] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 11/16/2012] [Indexed: 01/09/2023] Open
Abstract
Establishment of cell polarity is crucial for many biological processes including cell migration and asymmetric cell division. The establishment of cell polarity consists of two sequential processes: an external gradient is first sensed and then the resulting signal is amplified and maintained by intracellular signaling networks usually using positive feedback regulation. Generally, these two processes are intertwined and it is challenging to determine which proteins contribute to the sensing or amplification process, particularly in multicellular organisms. Here, we integrated phenomenological modeling with quantitative single-cell measurements to separate the sensing and amplification components of Wnt ligands and receptors during establishment of polarity of the Caenorhabditis elegans P cells. By systematically exploring how P-cell polarity is altered in Wnt ligand and receptor mutants, we inferred that ligands predominantly affect the sensing process, whereas receptors are needed for both sensing and amplification. This integrated approach is generally applicable to other systems and will facilitate decoupling of the different layers of signal sensing and amplification.
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Affiliation(s)
- Rui Zhen Tan
- Harvard University Graduate Biophysics Program, Harvard Medical School, Boston, MA, USA
| | - Ni Ji
- Department of Brian and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Remco A Mentink
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hendrik C Korswagen
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Alexander van Oudenaarden
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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61
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Xiao H, Li DX, Liu M. Knowledge translation: airway epithelial cell migration and respiratory diseases. Cell Mol Life Sci 2012; 69:4149-62. [PMID: 22718093 PMCID: PMC11115183 DOI: 10.1007/s00018-012-1044-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 05/23/2012] [Accepted: 05/25/2012] [Indexed: 12/17/2022]
Abstract
Airway epithelial cell migration is essential for lung development and growth, as well as the maintenance of respiratory tissue integrity. This vital cellular process is also important for the repair and regeneration of damaged airway epithelium. More importantly, several lung diseases characterized by aberrant tissue remodeling result from the improper repair of damaged respiratory tissue. Epithelial cell migration relies upon extracellular matrix molecules and is further regulated by numerous local, neuronal, and hormonal factors. Under inflammatory conditions, cell migration can also be stimulated by certain cytokines and chemokines. Many well-known environmental factors involved in the pathogenesis of chronic lung diseases (e.g., cigarette smoking, air pollution, alcohol intake, inflammation, viral and bacterial infections) can inhibit airway epithelial cell migration. Further investigation of cellular and molecular mechanisms of cell migration with advanced techniques may provide knowledge that is relevant to physiological and pathological conditions. These studies may eventually lead to the development of therapeutic interventions to improve lung repair and regeneration and to prevent aberrant remodeling in the lung.
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Affiliation(s)
- Helan Xiao
- Latner Thoracic Surgery Research Laboratories, Toronto General Research Institute, University Health Network, Toronto, ON Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON Canada
| | - Debbie X. Li
- Latner Thoracic Surgery Research Laboratories, Toronto General Research Institute, University Health Network, Toronto, ON Canada
| | - Mingyao Liu
- Latner Thoracic Surgery Research Laboratories, Toronto General Research Institute, University Health Network, Toronto, ON Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON Canada
- Departments of Surgery and Medicine, Faculty of Medicine, University of Toronto, Room TMDT 2-814, 101 College Street, Toronto, ON M5G 1L7 Canada
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62
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Xu Y, Quinn CC. MIG-10 functions with ABI-1 to mediate the UNC-6 and SLT-1 axon guidance signaling pathways. PLoS Genet 2012; 8:e1003054. [PMID: 23209429 PMCID: PMC3510047 DOI: 10.1371/journal.pgen.1003054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 09/07/2012] [Indexed: 11/30/2022] Open
Abstract
Extracellular guidance cues steer axons towards their targets by eliciting morphological changes in the growth cone. A key part of this process is the asymmetric recruitment of the cytoplasmic scaffolding protein MIG-10 (lamellipodin). MIG-10 is thought to asymmetrically promote outgrowth by inducing actin polymerization. However, the mechanism that links MIG-10 to actin polymerization is not known. We have identified the actin regulatory protein ABI-1 as a partner for MIG-10 that can mediate its outgrowth-promoting activity. The SH3 domain of ABI-1 binds to MIG-10, and loss of function of either of these proteins causes similar axon guidance defects. Like MIG-10, ABI-1 functions in both the attractive UNC-6 (netrin) pathway and the repulsive SLT-1 (slit) pathway. Dosage sensitive genetic interactions indicate that MIG-10 functions with ABI-1 and WVE-1 to mediate axon guidance. Epistasis analysis reveals that ABI-1 and WVE-1 function downstream of MIG-10 to mediate its outgrowth-promoting activity. Moreover, experiments with cultured mammalian cells suggest that the interaction between MIG-10 and ABI-1 mediates a conserved mechanism that promotes formation of lamellipodia. Together, these observations suggest that MIG-10 interacts with ABI-1 and WVE-1 to mediate the UNC-6 and SLT-1 guidance pathways. To form neural circuits, axons must navigate through the developing nervous system to reach their correct targets. Axon navigation is led by the growth cone, a structure at the tip of the growing axon that responds to extracellular guidance cues. Many of these guidance cues and their receptors have been identified. However, much less is known about the internal signaling events that give rise to the structural changes required for growth cone steering. A key component of the internal response is MIG-10, a protein that becomes asymmetrically localized in response to the extracellular cues. MIG-10 is thought to serve as a scaffold that can spatially control outgrowth-promoting proteins within the growth cone. However, we do not know the identity of the outgrowth-promoting proteins that associate with MIG-10. Here we report that MIG-10 associates physically with the actin regulatory protein ABI-1. We present genetic evidence indicating that ABI-1 functions downstream of MIG-10 to mediate its outgrowth-promoting activity. Additional genetic evidence indicates that these proteins function in both attractive and repulsive guidance signaling pathways. We also present evidence suggesting that the connection between MIG-10 and ABI-1 represents a phylogenetically conserved mechanism for the control of cellular outgrowth.
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Affiliation(s)
| | - Christopher C. Quinn
- Department of Biological Sciences, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, United States of America
- * E-mail:
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63
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Affiliation(s)
- Pei-lin Cheng
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan;
| | - Mu-ming Poo
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, 94720, USA;
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64
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Gao Y, Sun J, Lin WH, Webb D, Li D. A compact microfluidic gradient generator using passive pumping. MICROFLUIDICS AND NANOFLUIDICS 2012; 12:887-895. [PMID: 22737106 PMCID: PMC3377175 DOI: 10.1007/s10404-011-0908-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Creating and maintaining a precise molecular gradient which is stable in space and time are essential to studies of chemotaxis. This paper describes a simple, compact, and user-friendly microfluidic device using a passive pumping method to drive the liquid flow to generate a stable concentration gradient. A fluidic circuit is designed to offset the effects of the pressure imbalance between the two inlets. After loading approximately the same amount of culture media containing different concentrations of a certain chemotactic agent into the two inlet reservoirs, a linear concentration gradient will be automatically and quickly established at the downstream. Our device takes advantage of passive pumping and is compact enough to fit into a Petri dish, which is an attractive feature to biologists. Furthermore, this microfluidic gradient generator offers a platform for a facile way of long-term imaging and analysis using high resolution microscopy.
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Affiliation(s)
- Yandong Gao
- Department of Mechanical Engineering, Vanderbilt University, Nashville TN 37235
| | - Jiashu Sun
- Department of Mechanical Engineering, Vanderbilt University, Nashville TN 37235
| | - Wan-Hsin Lin
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235
| | - Donna Webb
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235
- Department of Cancer Biology, Vanderbilt University, Nashville, TN 37235
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville TN 37235
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Tibarewal P, Zilidis G, Spinelli L, Schurch N, Maccario H, Gray A, Perera NM, Davidson L, Barton GJ, Leslie NR. PTEN Protein Phosphatase Activity Correlates with Control of Gene Expression and Invasion, a Tumor-Suppressing Phenotype, But Not with AKT Activity. Sci Signal 2012; 5:ra18. [DOI: 10.1126/scisignal.2002138] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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66
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Mondal S, Subramanian KK, Sakai J, Bajrami B, Luo HR. Phosphoinositide lipid phosphatase SHIP1 and PTEN coordinate to regulate cell migration and adhesion. Mol Biol Cell 2012; 23:1219-30. [PMID: 22323291 PMCID: PMC3315799 DOI: 10.1091/mbc.e11-10-0889] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SHIP1 regulates PtdIns(3,4,5)P3 production in response to cell adhesion. Loss of SHIP1 leads to elevated PtdIns(3,4,5)P3 and Akt activation upon adhesion. SHIP1−/− neutrophils lose polarity upon cell adhesion. They are extremely adherent, which impairs chemotaxis. Chemotaxis in SHIP1−/− neutrophils can be rescued by reducing cell adhesion. The second messenger phosphatidylinositol(3,4,5)P3 (PtdIns(3,4,5)P3) is formed by stimulation of various receptors, including G protein–coupled receptors and integrins. The lipid phosphatases PTEN and SHIP1 are critical in regulating the level of PtdIns(3,4,5)P3 during chemotaxis. Observations that loss of PTEN had minor and loss of SHIP1 resulted in a severe chemotaxis defect in neutrophils led to the belief that SHIP1 rather than PTEN acts as a predominant phospholipid phosphatase in establishing a PtdIns(3,4,5)P3 compass. In this study, we show that SHIP1 regulates PtdIns(3,4,5)P3 production in response to cell adhesion and plays a limited role when cells are in suspension. SHIP1−/− neutrophils lose their polarity upon cell adhesion and are extremely adherent, which impairs chemotaxis. However, chemotaxis can be restored by reducing adhesion. Loss of SHIP1 elevates Akt activation following cell adhesion due to increased PtdIns(3,4,5)P3 production. From our observations, we conclude that SHIP1 prevents formation of top-down PtdIns(3,4,5)P3 polarity to facilitate proper cell attachment and detachment during chemotaxis.
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Affiliation(s)
- Subhanjan Mondal
- Department of Pathology, Harvard Medical School, Department of Laboratory Medicine, Children's Hospital Boston, Boston, MA 02115, USA
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67
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Van Haastert PJM. Amoeboid cells use protrusions for walking, gliding and swimming. PLoS One 2011; 6:e27532. [PMID: 22096590 PMCID: PMC3212573 DOI: 10.1371/journal.pone.0027532] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 10/19/2011] [Indexed: 01/20/2023] Open
Abstract
Amoeboid cells crawl using pseudopods, which are convex extensions of the cell surface. In many laboratory experiments, cells move on a smooth substrate, but in the wild cells may experience obstacles of other cells or dead material, or may even move in liquid. To understand how cells cope with heterogeneous environments we have investigated the pseudopod life cycle of wild type and mutant cells moving on a substrate and when suspended in liquid. We show that the same pseudopod cycle can provide three types of movement that we address as walking, gliding and swimming. In walking, the extending pseudopod will adhere firmly to the substrate, which allows cells to generate forces to bypass obstacles. Mutant cells with compromised adhesion can move much faster than wild type cells on a smooth substrate (gliding), but cannot move effectively against obstacles that provide resistance. In a liquid, when swimming, the extending pseudopods convert to side-bumps that move rapidly to the rear of the cells. Calculations suggest that these bumps provide sufficient drag force to mediate the observed forward swimming of the cell.
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68
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Mogilner A, Odde D. Modeling cellular processes in 3D. Trends Cell Biol 2011; 21:692-700. [PMID: 22036197 DOI: 10.1016/j.tcb.2011.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 09/23/2011] [Accepted: 09/23/2011] [Indexed: 10/15/2022]
Abstract
Recent advances in photonic imaging and fluorescent protein technology offer unprecedented views of molecular space-time dynamics in living cells. At the same time, advances in computing hardware and software enable modeling of ever more complex systems, from global climate to cell division. As modeling and experiment become more closely integrated we must address the issue of modeling cellular processes in 3D. Here, we highlight recent advances related to 3D modeling in cell biology. While some processes require full 3D analysis, we suggest that others are more naturally described in 2D or 1D. Keeping the dimensionality as low as possible reduces computational time and makes models more intuitively comprehensible; however, the ability to test full 3D models will build greater confidence in models generally and remains an important emerging area of cell biological modeling.
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Affiliation(s)
- Alex Mogilner
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, USA.
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69
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Axl2 integrates polarity establishment, maintenance, and environmental stress response in the filamentous fungus Ashbya gossypii. EUKARYOTIC CELL 2011; 10:1679-93. [PMID: 21984708 DOI: 10.1128/ec.05183-11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In budding yeast, new sites of polarity are chosen with each cell cycle and polarization is transient. In filamentous fungi, sites of polarity persist for extended periods of growth and new polarity sites can be established while existing sites are maintained. How the polarity establishment machinery functions in these distinct growth forms found in fungi is still not well understood. We have examined the function of Axl2, a transmembrane bud site selection protein discovered in Saccharomyces cerevisiae, in the filamentous fungus Ashbya gossypii. A. gossypii does not divide by budding and instead exhibits persistent highly polarized growth, and multiple axes of polarity coexist in one cell. A. gossypii axl2Δ (Agaxl2Δ) cells have wavy hyphae, bulbous tips, and a high frequency of branch initiations that fail to elongate, indicative of a polarity maintenance defect. Mutant colonies also have significantly lower radial growth and hyphal tip elongation speeds than wild-type colonies, and Agaxl2Δ hyphae have depolarized actin patches. Consistent with a function in polarity, AgAxl2 localizes to hyphal tips, branches, and septin rings. Unlike S. cerevisiae Axl2, AgAxl2 contains a Mid2 homology domain and may function to sense or respond to environmental stress. In support of this idea, hyphae lacking AgAxl2 also display hypersensitivity to heat, osmotic, and cell wall stresses. Axl2 serves to integrate polarity establishment, polarity maintenance, and environmental stress response for optimal polarized growth in A. gossypii.
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G protein-coupled receptor signaling and sphingosine-1-phosphate play a phylogenetically conserved role in endocrine pancreas morphogenesis. Mol Cell Biol 2011; 31:4442-53. [PMID: 21911471 DOI: 10.1128/mcb.05702-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
During development pancreatic endocrine cells migrate in a coordinated fashion. This migration is necessary to form fully functional islets, but the mechanisms involved remain unknown. Therapeutic strategies to restore β-cell mass and islet functionality by reprogramming endogenous exocrine cells would be strengthened from simultaneous treatments that enhance endocrine cell clustering. We found that endocrine progenitors respond to and regulate G protein-coupled receptor (GPCR) signaling in order to cluster in islets. Rgs4, a dedicated regulator of GPCR signaling, was specifically expressed in early epithelial endocrine progenitors of both zebrafish and mouse, and its expression in the mouse endocrine progenitors was strictly dependent upon Ngn3, the key specification gene of the endocrine lineage. Rgs4 loss of function resulted in defects in islet cell aggregation. By genetically inactivating Gα(i)-mediated GPCR signaling in endocrine progenitors, we established its role in islet cell aggregation in both mouse and zebrafish. Finally, we identified sphingosine-1-phosphate (S1P) as a ligand mediating islet cell aggregation in both species acting through distinct but closely related receptors.
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Abstract
Chemotaxis of tumour cells and stromal cells in the surrounding microenvironment is an essential component of tumour dissemination during progression and metastasis. This Review summarizes how chemotaxis directs the different behaviours of tumour cells and stromal cells in vivo, how molecular pathways regulate chemotaxis in tumour cells and how chemotaxis choreographs cell behaviour to shape the tumour microenvironment and to determine metastatic spread. The central importance of chemotaxis in cancer progression is highlighted by discussion of the use of chemotaxis as a prognostic marker, a treatment end point and a target of therapeutic intervention.
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Affiliation(s)
- Evanthia T Roussos
- Department of Anatomy and Structural Biology, Program in Tumor Microenvironment and Metastasis, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461, USA
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Sun YH, Reid B, Fontaine JH, Miller LA, Hyde DM, Mogilner A, Zhao M. Airway epithelial wounds in rhesus monkey generate ionic currents that guide cell migration to promote healing. J Appl Physiol (1985) 2011; 111:1031-41. [PMID: 21719726 DOI: 10.1152/japplphysiol.00915.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Damage to the respiratory epithelium is one of the most critical steps to many life-threatening diseases, such as acute respiratory distress syndrome and chronic obstructive pulmonary disease. The mechanisms underlying repair of the damaged epithelium have not yet been fully elucidated. Here we provide experimental evidence suggesting a novel mechanism for wound repair: endogenous electric currents. It is known that the airway epithelium maintains a voltage difference referred to as the transepithelial potential. Using a noninvasive vibrating probe, we demonstrate that wounds in the epithelium of trachea from rhesus monkeys generate significant outward electric currents. A small slit wound produced an outward current (1.59 μA/cm(2)), which could be enhanced (nearly doubled) by the ion transport stimulator aminophylline. In addition, inhibiting cystic fibrosis transmembrane conductance regulator (CFTR) with CFTR(Inh)-172 significantly reduced wound currents (0.17 μA/cm(2)), implicating an important role of ion transporters in wound induced electric potentials. Time-lapse video microscopy showed that applied electric fields (EFs) induced robust directional migration of primary tracheobronchial epithelial cells from rhesus monkeys, towards the cathode, with a threshold of <23 mV/mm. Reversal of the field polarity induced cell migration towards the new cathode. We further demonstrate that application of an EF promoted wound healing in a monolayer wound healing assay. Our results suggest that endogenous electric currents at sites of tracheal epithelial injury may direct cell migration, which could benefit restitution of damaged airway mucosa. Manipulation of ion transport may lead to novel therapeutic approaches to repair damaged respiratory epithelium.
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Affiliation(s)
- Yao-Hui Sun
- Department of Dermatology, School of Medicine, Univ. of California at Davis CA, Sacramento, CA 95817, USA
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73
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Chemotactic cell trapping in controlled alternating gradient fields. Proc Natl Acad Sci U S A 2011; 108:11417-22. [PMID: 21709255 DOI: 10.1073/pnas.1014853108] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Directed cell migration toward spatio-temporally varying chemotactic stimuli requires rapid cytoskeletal reorganization. Numerous studies provide evidence that actin reorganization is controlled by intracellular redistribution of signaling molecules, such as the PI4,5P2/PI3,4,5P3 gradient. However, exploring underlying mechanisms is difficult and requires careful spatio-temporal control of external chemotactic stimuli. We designed a microfluidic setup to generate alternating chemotactic gradient fields for simultaneous multicell exposure, greatly facilitating statistical analysis. For a quantitative description of intracellular response dynamics, we apply alternating time sequences of spatially homogeneous concentration gradients across 300 μm, reorienting on timescales down to a few seconds. Dictyostelium discoideum amoebae respond to gradient switching rates below 0.02 Hz by readapting their migration direction. For faster switching, cellular repolarization ceases and is completely stalled at 0.1 Hz. In this "chemotactically trapped" cell state, external stimuli alternate faster than intracellular feedback is capable to respond by onset of directed migration. To investigate intracellular actin cortex rearrangement during gradient switching, we correlate migratory cell response with actin repolymerization dynamics, quantified by a fluorescence distribution moment of the GFP fusion protein LimEΔcc. We find two fundamentally different cell polarization types and we could reveal the role of PI3-Kinase for cellular repolarization. In the early aggregation phase, PI3-Kinase enhances the capability of D. discoideum cells to readjust their polarity in response to spatially alternating gradient fields, whereas in aggregation competent cells the effect of PI3-Kinase perturbation becomes less relevant.
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Parameswaran N, Matsui K, Gupta N. Conformational switching in ezrin regulates morphological and cytoskeletal changes required for B cell chemotaxis. THE JOURNAL OF IMMUNOLOGY 2011; 186:4088-97. [PMID: 21339367 DOI: 10.4049/jimmunol.1001139] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
B cell chemotaxis occurs in response to specific chemokine gradients and is critical for homeostasis and immune response. The molecular regulation of B cell membrane-actin interactions during migration is poorly understood. In this study, we report a role for ezrin, a member of the membrane-cytoskeleton cross-linking ezrin-radixin-moesin proteins, in the regulation of the earliest steps of B cell polarization and chemotaxis. We visualized chemokine-induced changes in murine B cell morphology using scanning electron microscopy and spatiotemporal dynamics of ezrin in B cells using epifluorescence and total internal reflection microscopy. Upon chemokine stimulation, ezrin is transiently dephosphorylated to assume an inactive conformation and localizes to the lamellipodia. B cells expressing a phosphomimetic conformationally active mutant of ezrin or those in which ezrin dephosphorylation was pharmacologically inhibited displayed impaired microvillar dynamics, morphological polarization, and chemotaxis. Our data suggest a 2-fold involvement of ezrin in B cell migration, whereby it first undergoes chemokine-induced dephosphorylation to facilitate membrane flexibility, followed by relocalization to the actin-rich lamellipodia for dynamic forward protrusion of the cells.
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Affiliation(s)
- Neetha Parameswaran
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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Abstract
Chemotaxis is one of the most fascinating processes in cell biology. Shallow gradients of chemoattractant direct the movement of cells, and an intricate network of signalling pathways somehow instructs the movement apparatus to induce pseudopods in the direction of these gradients. Exciting new experiments have approached chemotaxis from the perspective of the extending pseudopod. These recent studies have revealed that, in the absence of external cues, cells use endogenous signals for the highly ordered extension of pseudopods, which appear mainly as alternating right and left splits. In addition, chemoattractants activate other signalling molecules that induce a positional bias of this basal system, such that the extending pseudopods are oriented towards the gradient. In this Commentary, I review the findings of these recent experiments, which together provide a new view of cell movement and chemotaxis.
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Affiliation(s)
- Peter J M Van Haastert
- Department of Cell Biochemistry, University of Groningen, Kerklaan 30, 9751NN Haren, The Netherlands.
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Xu W, Wang P, Petri B, Zhang Y, Tang W, Sun L, Kress H, Mann T, Shi Y, Kubes P, Wu D. Integrin-induced PIP5K1C kinase polarization regulates neutrophil polarization, directionality, and in vivo infiltration. Immunity 2010; 33:340-50. [PMID: 20850356 DOI: 10.1016/j.immuni.2010.08.015] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 07/19/2010] [Accepted: 08/11/2010] [Indexed: 11/15/2022]
Abstract
Neutrophils are important in innate immunity and acute inflammatory responses. However, the regulation of their recruitment to sites of inflammation has not been well characterized. Here, we investigated the kinase PIP5K1C and showed that PIP5K1C deficiency impaired neutrophil recruitment because of an adhesion defect. PIP5K1C regulated the adhesion through facilitating RhoA GTPase and integrin activation by chemoattractants. Integrins could induce polarization of an isoform of PIP5K1C, PIP5K1C-90, in neutrophils through intracellular vesicle transport independently of exogenous chemoattractant. PIP5K1C-90 polarization was required for polarized RhoA activation at uropods and provided an initial directional cue for neutrophil polarization on the endothelium. Importantly, the polarization was also required for circumventing the inhibition of lamellipodium formation by RhoA so that neutrophils could form leading edges required for transendothelial migration. Because integrins are not known to regulate neutrophil polarization, our study revealed a previously underappreciated role of integrin signaling in neutrophil regulation.
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Affiliation(s)
- Wenwen Xu
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, China
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Jagannathan K, Calhoun VD, Gelernter J, Stevens MC, Liu J, Bolognani F, Windemuth A, Ruaño G, Assaf M, Pearlson GD. Genetic associations of brain structural networks in schizophrenia: a preliminary study. Biol Psychiatry 2010; 68:657-66. [PMID: 20691427 PMCID: PMC2990476 DOI: 10.1016/j.biopsych.2010.06.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 05/25/2010] [Accepted: 06/03/2010] [Indexed: 11/29/2022]
Abstract
BACKGROUND Schizophrenia is a complex genetic disorder, with multiple putative risk genes and many reports of reduced cortical gray matter. Identifying the genetic loci contributing to these structural alterations in schizophrenia (and likely also to normal structural gray matter patterns) could aid understanding of schizophrenia's pathophysiology. We used structural parameters as potential intermediate illness markers to investigate genomic factors derived from single nucleotide polymorphism (SNP) arrays. METHOD We used research quality structural magnetic resonance imaging (sMRI) scans from European American subjects including 33 healthy control subjects and 18 schizophrenia patients. All subjects were genotyped for 367 SNPs. Linked sMRI and genetic (SNP) components were extracted to reveal relationships between brain structure and SNPs, using parallel independent component analysis, a novel multivariate approach that operates effectively in small sample sizes. RESULTS We identified an sMRI component that significantly correlated with a genetic component (r = -.536, p < .00005); components also distinguished groups. In the sMRI component, schizophrenia gray matter deficits were in brain regions consistently implicated in previous reports, including frontal and temporal lobes and thalamus (p < .01). These deficits were related to SNPs from 16 genes, several previously associated with schizophrenia risk and/or involved in normal central nervous system development, including AKT, PI3K, SLC6A4, DRD2, CHRM2, and ADORA2A. CONCLUSIONS Despite the small sample size, this novel analysis method identified an sMRI component including brain areas previously reported to be abnormal in schizophrenia and an associated genetic component containing several putative schizophrenia risk genes. Thus, we identified multiple genes potentially underlying specific structural brain abnormalities in schizophrenia.
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Affiliation(s)
- Kanchana Jagannathan
- Olin Neuropsychiatry Research Center, Institute of Living/Hartford Hospital, Hartford, Connecticut 06106, USA.
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79
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Kandere-Grzybowska K, Soh S, Mahmud G, Komarova Y, Pilans D, Grzybowski BA. Short-term molecular polarization of cells on symmetric and asymmetric micropatterns. SOFT MATTER 2010; 6:3257-3268. [PMID: 23826026 PMCID: PMC3697907 DOI: 10.1039/b922647h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The ability of cells to sense geometrical/physical constraints of local environment is important for cell movements during development, immune surveillance, and in cancer invasion. In this paper, we quantify "front-rear" polarization - the crucial step in initiating cell migration - based on cytoskeleton and substrate adhesion anisotropy in micropatterned cells of well-defined shapes. We then show that the general viewpoint that asymmetric cell shape is one of the defining characteristics of polarized cells is incomplete. Specifically, we demonstrate that cells on circular micropatterned islands can exhibit asymmetric distribution of both filamentous actin (f-actin) and focal adhesions (FAs) as well as directional, lamellipodial-like ruffling activity. This asymmetry, however, is transient and persists only for the period of several hours during which actin filaments and adhesion structures reorganize into symmetric peripheral arrangement. Cells on asymmetric tear-drop shape islands also display polarized f-actin and FAs, but polarization axes are oriented towards the wide end of the islands. Polarization of actin filaments on tear-drop islands is short-term, while focal adhesions remain asymmetrically distributed for long times. From a practical perspective, circular cells constitute a convenient experimental system, in which phenomena related to cell polarization are "decoupled" from the effects of cells' local curvature (constant along circular cell's perimeter), while asymmetric (tear-drop) micropatterned cells standardize the organization of motility machinery of polarized/ moving cells. Both systems may prove useful for the design of diagnostic tools with which to probe and quantify ex vivo the motility/invasiveness status of cells from cancer patients.
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Affiliation(s)
- Kristiana Kandere-Grzybowska
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA
| | - Siowling Soh
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA
| | - Goher Mahmud
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA
| | - Yulia Komarova
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA
| | - Didzis Pilans
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA
| | - Bartosz A. Grzybowski
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA
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Integrins and ion channels in cell migration: implications for neuronal development, wound healing and metastatic spread. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 674:107-23. [PMID: 20549944 DOI: 10.1007/978-1-4419-6066-5_10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cells migration is necessary for proper embryonic development and adult tissue remodeling. Its mechanisms determine the physiopathology of processes such as neuronal targeting, inflammation, wound healing and metastatic spread. Crawling of cells onto solid surfaces requires a controlled sequence of cell protrusions and retractions that mainly depends on sophisticated regulation of the actin cytoskeleton, although the contribution of microtubules should not be neglected. This process is triggered and modulated by a combination of diffusible and fixed environmental signals. External cues are sensed and integrated by membrane receptors, including integrins, which transduce these signals into cellular signaling pathways, often centered on the small GTPase proteins belonging to the Rho family. These pathways regulate the coordinated cytoskeletal rearrangements necessary for proper timing of adhesion, contraction and detachement at the front and rear side of cells finding their way through the extracellular spaces. The overall process involves continuous modulation of cell motility, shape and volume, in which ion channels play major roles. In particular, Ca2+ signals have both global and local regulatory effects on cell motility, because they target the contractile proteins as well as many regulatory proteins. After reviewing the fundamental mechanisms of eukaryotic cell migration onto solid substrates, we briefly describe how integrin receptors and ion channels are involved in cell movement. We next examine a few processes in which these mechanisms have been studied in depth. We thus illustrate how integrins and K+ channels control cell volume and migration, how intracellular Ca2+ homeostasis affects the motility of neuronal growth cones and what is known about the ion channel roles in epithelial cell migration. These mechanisms are implicated in a variety of pathological processes, such as the disruption of neural circuits and wound healing. Finally, we describe the interaction between neoplastic cells and their local environment and how derangement of adhesion can lead to metastatic spread. It is likely that the cellular mechanisms controlled by integrin receptors, ion channels or both participate in the entire metastatic process. Until now, however, evidence is limited to a few steps of the metastatic cascade, such as brain tumor invasiveness.
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Ellis IR, Jones SJ, Lindsay Y, Ohe G, Schor AM, Schor SL, Leslie NR. Migration Stimulating Factor (MSF) promotes fibroblast migration by inhibiting AKT. Cell Signal 2010; 22:1655-9. [PMID: 20600851 DOI: 10.1016/j.cellsig.2010.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 06/15/2010] [Accepted: 06/21/2010] [Indexed: 11/16/2022]
Abstract
The protein kinase AKT is activated strongly by many motogenic growth factors, yet has recently been shown capable of inhibiting migration in several cell types. Here we report that treatment with Migration Stimulating Factor (MSF), a truncated form of fibronectin that promotes the migration of many cell types, inhibits AKT activity in human fibroblasts and endothelial cells. In fibroblasts, treatment with either MSF or the AKT inhibitor, Akti-1/2, stimulated migration into 3D collagen gels to a similar extent and the effects of Akti-1/2 on migration could be blocked by the expression of an inhibitor-resistant mutant, AKT1 W80A. These data indicate that MSF promotes fibroblast migration, at least in part, by inhibiting the activity of AKT.
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Affiliation(s)
- Ian R Ellis
- Unit of Cell and Molecular Biology, The Dental School, College of Medicine, Dentistry and Nursing, University of Dundee, Park Place, Dundee DD1 4HR, UK
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Alam-Nazki A, Krishnan J. A mathematical modelling framework for understanding chemorepulsive signal transduction in Dictyostelium. J Theor Biol 2010; 266:140-53. [PMID: 20510250 DOI: 10.1016/j.jtbi.2010.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 05/11/2010] [Accepted: 05/14/2010] [Indexed: 12/22/2022]
Abstract
Chemorepulsion is the process by which an organism or a cell moves in the direction of decreasing chemical concentration. While a few experimental studies have been performed, no mathematical models exist for this process. In this paper we have modelled gradient sensing, the first subprocess of chemorepulsion, in Dictyostelium discoideum-a well characterized model eukaryotic system. We take the first steps towards achieving a comprehensive mechanistic understanding of chemorepulsion in this system. We have used, as a basis, the biochemical network of the Keizer-Gunnink et al. (2007) to develop the mathematical modelling framework. This network describes the underlying pathways of chemorepellent gradient sensing in D. discoideum. Working within this modelling framework we address whether the postulated interactions of the pathways and species in this network can lead to a chemorepulsive response. We also analyse the possible role of additional regulatory effects (such as additional receptor regulation of enzymes in this network) and if this is necessary to achieve this behaviour. Thus we have investigated the receptor regulation of important enzymes and feedback effects in the network. This modelling framework generates important insights into and testable predictions regarding the role of key components and feedback loops in regulating chemorepulsive gradient sensing, and what factors might be important for generating a chemorepulsive response; it serves as a first step towards a comprehensive mechanistic understanding of this process.
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Affiliation(s)
- Aiman Alam-Nazki
- Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
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83
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Mañes S, Fuentes G, Peregil RM, Rojas AM, Lacalle RA. An isoform-specific PDZ-binding motif targets type I PIP5 kinase beta to the uropod and controls polarization of neutrophil-like HL60 cells. FASEB J 2010; 24:3381-92. [PMID: 20442317 DOI: 10.1096/fj.09-153106] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Type I phosphatidylinositol 4-phosphate 5-kinase (PIP5KI)-beta participates in establishing polarity during leukocyte chemotaxis. Its final 83 amino acids localize PIP5KIbeta to the uropod of chemotaxing neutrophils and T cells, and interact with ezrin-radixin-moesin (ERM) proteins and EBP50 (4.1-ERM-binding phosphoprotein 50), a scaffold protein with 2 PDZ (PSD-95, disc large, ZO-1) domains. The structural motifs at the PIP5KIbeta C terminus that confer signaling specificity are, nonetheless, unknown. We show that the last 4 residues of PIP5KIbeta constitute an atypical PDZ-binding motif, which steers PIP5KIbeta to the uropod by binding to both EBP50 PDZ domains. Molecular modeling and mutagenesis indicated that PDZ-binding motif is necessary for PIP5KIbeta localization and for chemoattractant-induced neutrophil polarization. Polarity in cells that express PIP5KIbeta mutants lacking the PDZ-binding motif was restored by overexpression of PIP5KIbeta, but not of PIP5KIgamma_i2, another isoform that localizes to the neutrophil uropod. Our results identify an isoform-specific PDZ-binding motif in PIP5KIbeta, which confers specificity for PIP5KIbeta signaling at the uropod during leukocyte chemotaxis.
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Affiliation(s)
- Santos Mañes
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Científicas, Darwin 3, Campus de Cantoblanco, Madrid E-28049, Spain
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Raman D, Sai J, Neel NF, Chew CS, Richmond A. LIM and SH3 protein-1 modulates CXCR2-mediated cell migration. PLoS One 2010; 5:e10050. [PMID: 20419088 PMCID: PMC2856662 DOI: 10.1371/journal.pone.0010050] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 03/16/2010] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The chemokine receptor CXCR2 plays a pivotal role in migration of neutrophils, macrophages and endothelial cells, modulating several biological responses such as angiogenesis, wound healing and acute inflammation. CXCR2 is also involved in pathogenesis of chronic inflammation, sepsis and atherosclerosis. The ability of CXCR2 to associate with a variety of proteins dynamically is responsible for its effects on directed cell migration or chemotaxis. The dynamic network of such CXCR2 binding proteins is termed as "CXCR2 chemosynapse". Proteomic analysis of proteins that co-immunoprecipitated with CXCR2 in neutrophil-like dHL-60 cells revealed a novel protein, LIM and SH3 protein 1 (LASP-1), binds CXCR2 under both basal and ligand activated conditions. LASP-1 is an actin binding cytoskeletal protein, involved in the cell migration. METHODOLOGY/PRINCIPAL FINDINGS We demonstrate that CXCR2 and LASP-1 co-immunoprecipitate and co-localize at the leading edge of migrating cells. The LIM domain of LASP-1 directly binds to the carboxy-terminal domain (CTD) of CXCR2. Moreover, LASP-1 also directly binds the CTD of CXCR1, CXCR3 and CXCR4. Using a site-directed and deletion mutagenesis approach, Iso323-Leu324 of the conserved LKIL motif on CXCR2-CTD was identified as the binding site for LASP-1. Interruption of the interaction between CXCR2-CTD and LIM domain of LASP-1 by dominant negative and knock down approaches inhibited CXCR2-mediated chemotaxis. Analysis for the mechanism for inhibition of CXCR2-mediated chemotaxis indicated that LASP-1/CXCR2 interaction is essential for cell motility and focal adhesion turnover involving activation of Src, paxillin, PAK1, p130CAS and ERK1/2. CONCLUSIONS/SIGNIFICANCE We demonstrate here for the first time that LASP-1 is a key component of the "CXCR2 chemosynapse" and LASP-1 interaction with CXCR2 is critical for CXCR2-mediated chemotaxis. Furthermore, LASP-1 also directly binds the CTD of CXCR1, CXCR3 and CXCR4, suggesting that LASP-1 is a general mediator of CXC chemokine mediated chemotaxis. Thus, LASP-1 may serve as a new link coordinating the flow of information between chemokine receptors and nascent focal adhesions, especially at the leading edge. Thus the association between the chemokine receptors and LASP-1 suggests to the presence of a CXC chemokine receptor-LASP-1 pro-migratory module in cells governing the cell migration.
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Affiliation(s)
- Dayanidhi Raman
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Jiqing Sai
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Nicole F. Neel
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Catherine S. Chew
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia, United States of America
| | - Ann Richmond
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Veterans Affairs, Nashville, Tennessee, United States of America
- * E-mail:
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Suchkov DV, DeFlorio R, Draper E, Ismael A, Sukumar M, Arkowitz R, Stone DE. Polarization of the yeast pheromone receptor requires its internalization but not actin-dependent secretion. Mol Biol Cell 2010; 21:1737-52. [PMID: 20335504 PMCID: PMC2869379 DOI: 10.1091/mbc.e09-08-0706] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The data presented in this paper suggest that pheromone-induced receptor phosphorylation and internalization, but not actin-dependent directed secretion, are required to establish receptor polarity. In the best understood models of eukaryotic directional sensing, chemotactic cells maintain a uniform distribution of surface receptors even when responding to chemical gradients. The yeast pheromone receptor is also uniformly distributed on the plasma membrane of vegetative cells, but pheromone induces its polarization into “crescents” that cap the future mating projection. Here, we find that in pheromone-treated cells, receptor crescents are visible before detectable polarization of actin cables and that the receptor can polarize in the absence of actin-dependent directed secretion. Receptor internalization, in contrast, seems to be essential for the generation of receptor polarity, and mutations that deregulate this process confer dramatic defects in directional sensing. We also show that pheromone induces the internalization and subsequent polarization of the mating-specific Gα and Gβ proteins and that the changes in G protein localization depend on receptor internalization and receptor–Gα coupling. Our data suggest that the polarization of the receptor and its G protein precedes actin polarization and is important for gradient sensing. We propose that the establishment of receptor/G protein polarity depends on a novel mechanism involving differential internalization and that this serves to amplify the shallow gradient of activated receptor across the cell.
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Affiliation(s)
- Dmitry V Suchkov
- Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
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Coordination between extrinsic extracellular matrix cues and intrinsic responses to orient the centrosome in polarizing cerebellar granule neurons. J Neurosci 2010; 30:2755-66. [PMID: 20164359 DOI: 10.1523/jneurosci.4218-09.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Successful axon targeting during development is critically dependent on directionality of axon extension and requires coordination between the extrinsic cues that provide spatial information to the axon and the intrinsic responses that regulate structural specification of the axon during neuronal polarization. How these responses are coordinated is unclear but are known to involve aligning the centrosome with the base of the emerging axon. We have used a novel in vitro micropatterning assay that spatially segregates the extrinsic cues used by polarizing cerebellar granule cells to orient axon extension and used it to investigate the signaling mechanisms responsible for coordinating centrosome positioning with intrinsic responses. The results show that, when laminin and/or vitronectin are used as spatially restricted cues in association with substrate-associated sonic hedgehog, they are sufficient to induce cell cycle arrest, that laminin and vitronectin then induce integrin-mediated signaling that upregulates phosphoinositide-3 kinase and PKC function to produce phosphatidylinositol 3,4,5-trisphosphate (PIP3) that is associated with the centrosome, that this PIP3 can interact with PKC-phosphorylated growth-associated protein GAP-43, and that PKC-phosphorylated GAP-43 in turn is required for positioning Par6, Cdc42, and IQGAP1, all intrinsic response components, in proximity to the centrosome, such that, in the absence of GAP-43, they are mislocalized and microtubules are not oriented appropriately. We conclude from these results that GAP-43 plays an important role in coordinating extrinsic signaling and intrinsic responses in polarizing cerebellar granule neurons.
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87
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Abstract
Cytoskeletal systems are networks of polymers found in all eukaryotic and many prokaryotic cells. Their purpose is to transmit and integrate information across cellular dimensions and help turn a disorderly mob of macromolecules into a spatially organized, living cell. Information, in this context, includes physical and chemical properties relevant to cellular physiology, including: the number and activity of macromolecules, cell shape, and mechanical force. Most animal cells are 10-50 microns in diameter, whereas the macromolecules that comprise them are 10,000-fold smaller (2-20 nm). To establish long-range order over cellular length scales, individual molecules must, therefore, self-assemble into larger polymers, with lengths (0.1-20 m) comparable to the size of a cell. These polymers must then be cross-linked into organized networks that fill the cytoplasm. Such cell-spanning polymer networks enable different parts of the cytoplasm to communicate directly with each other, either by transmitting forces or by carrying cargo from one spot to another.
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Affiliation(s)
- R Dyche Mullins
- N312F Genentech Hall, UCSF School of Medicine, 600 16th Street, San Francisco, California 94158, USA.
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88
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Kress H, Park JG, Mejean CO, Forster JD, Park J, Walse SS, Zhang Y, Wu D, Weiner OD, Fahmy TM, Dufresne ER. Cell stimulation with optically manipulated microsources. Nat Methods 2009; 6:905-9. [PMID: 19915561 DOI: 10.1038/nmeth.1400] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 10/13/2009] [Indexed: 12/19/2022]
Abstract
Molecular gradients are important for various biological processes including the polarization of tissues and cells during embryogenesis and chemotaxis. Investigations of these phenomena require control over the chemical microenvironment of cells. We present a technique to set up molecular concentration patterns that are chemically, spatially and temporally flexible. Our strategy uses optically manipulated microsources, which steadily release molecules. Our technique enables the control of molecular concentrations over length scales down to about 1 microm and timescales from fractions of a second to an hour. We demonstrate this technique by manipulating the motility of single human neutrophils. We induced directed cell polarization and migration with microsources loaded with the chemoattractant formyl-methionine-leucine-phenylalanine. Furthermore, we triggered highly localized retraction of lamellipodia and redirection of polarization and migration with microsources releasing cytochalasin D, an inhibitor of actin polymerization.
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Affiliation(s)
- Holger Kress
- Department of Mechanical Engineering, Yale University, New Haven, Connecticut, USA.
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89
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Abstract
Chemotaxis--the directed movement of cells in a gradient of chemoattractant--is essential for neutrophils to crawl to sites of inflammation and infection and for Dictyostelium discoideum (D. discoideum) to aggregate during morphogenesis. Chemoattractant-induced activation of spatially localized cellular signals causes cells to polarize and move toward the highest concentration of the chemoattractant. Extensive studies have been devoted to achieving a better understanding of the mechanism(s) used by a neutrophil to choose its direction of polarity and to crawl effectively in response to chemoattractant gradients. Recent technological advances are beginning to reveal many fascinating details of the intracellular signaling components that spatially direct the cytoskeleton of neutrophils and D. discoideum and the complementary mechanisms that make the cell's front distinct from its back.
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Affiliation(s)
- Fei Wang
- Department of Cell and Developmental Biology and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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90
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Loo LH, Lin HJ, Steininger RJ, Wang Y, Wu LF, Altschuler SJ. An approach for extensibly profiling the molecular states of cellular subpopulations. Nat Methods 2009; 6:759-65. [PMID: 19767759 DOI: 10.1038/nmeth.1375] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 08/25/2009] [Indexed: 11/09/2022]
Abstract
Microscopy often reveals the existence of phenotypically distinct cellular subpopulations. However, additional characterization of observed subpopulations can be limited by the number of biomolecular markers that can be simultaneously monitored. Here we present a computational approach for extensibly profiling cellular subpopulations by freeing one or more imaging channels to monitor additional probes. In our approach, we trained classifiers to re-identify subpopulations accurately based on an enhanced collection of phenotypic features extracted from only a subset of the original markers. Then we constructed subpopulation profiles step-wise from replicate experiments, in which cells were labeled with different but overlapping marker sets. We applied our approach to identify molecular differences among subpopulations and to identify functional groupings of markers, in populations of differentiating mouse preadipocytes, polarizing human neutrophil-like cells and dividing human cancer cells.
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Affiliation(s)
- Lit-Hsin Loo
- Green Center for Systems Biology and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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91
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Duman-Scheel M. Netrin and DCC: axon guidance regulators at the intersection of nervous system development and cancer. Curr Drug Targets 2009; 10:602-10. [PMID: 19601764 DOI: 10.2174/138945009788680428] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In recent years, a number of axon guidance genes, including Netrin (Net) and Deleted in Colorectal Cancer (DCC), have been implicated in human cancers. Many of the hallmarks of human cancer, such as cell growth, invasion, evasion of apoptosis, and formation of a blood supply to the tumor, involve cellular processes that are critical during nervous system development. Here, the roles of Net-DCC in the regulation of these cellular processes in tumors and developing neurons are discussed. The advantages of using Drosophila to study the function of Net-DCC and other axon guidance molecules in these cellular processes, as well as the potential for cancer therapeutics targeting Net-DCC are highlighted.
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Affiliation(s)
- M Duman-Scheel
- Indiana University School of Medicine-South Bend at Notre Dame, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA.
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92
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Tayalia P, Mooney DJ. Controlled growth factor delivery for tissue engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2009; 21:3269-3285. [PMID: 20882497 DOI: 10.1002/adma.200900241] [Citation(s) in RCA: 262] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Growth factors play a crucial role in information transfer between cells and their microenvironment in tissue engineering and regeneration. They initiate their action by binding to specific receptors on the surface of target cells and the chemical identity, concentration, duration, and context of these growth factors contain information that dictates cell fate. Hence, the importance of exogenous delivery of these molecules in tissue engineering is unsurprising, considering their importance for tissue regeneration. However, the short half-lives of growth factors, their relatively large size, slow tissue penetration, and their potential toxicity at high systemic levels, suggest that conventional routes of administration are unlikely to be effective. In this review, we provide an overview of the design criteria for growth factor delivery vehicles with respect to the growth factor itself and the microenvironment for delivery. We discuss various methodologies that could be adopted to achieve this localized delivery, and strategies using polymers as delivery vehicles in particular.
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93
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Bosgraaf L, Van Haastert PJM. Navigation of chemotactic cells by parallel signaling to pseudopod persistence and orientation. PLoS One 2009; 4:e6842. [PMID: 19718261 PMCID: PMC2729408 DOI: 10.1371/journal.pone.0006842] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 08/07/2009] [Indexed: 01/05/2023] Open
Abstract
The mechanism of chemotaxis is one of the most interesting issues in modern cell biology. Recent work shows that shallow chemoattractant gradients do not induce the generation of pseudopods, as has been predicted in many models. This poses the question of how else cells can steer towards chemoattractants. Here we use a new computational algorithm to analyze the extension of pseudopods by Dictyostelium cells. We show that a shallow gradient of cAMP induces a small bias in the direction of pseudopod extension, without significantly affecting parameters such as pseudopod frequency or size. Persistent movement, caused by alternating left/right splitting of existing pseudopodia, amplifies the effects of this bias by up to 5-fold. Known players in chemotactic pathways play contrasting parts in this mechanism; PLA2 and cGMP signal to the cytoskeleton to regulate the splitting process, while PI 3-kinase and soluble guanylyl cyclase mediate the directional bias. The coordinated regulation of pseudopod generation, orientation and persistence by multiple signaling pathways allows eukaryotic cells to detect extremely shallow gradients.
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Affiliation(s)
- Leonard Bosgraaf
- Department of Cell Biochemistry, University of Groningen, Haren, The Netherlands
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94
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The roles of multiple UNC-40 (DCC) receptor-mediated signals in determining neuronal asymmetry induced by the UNC-6 (netrin) ligand. Genetics 2009; 183:941-9. [PMID: 19704011 DOI: 10.1534/genetics.109.108654] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The polarization of post-mitotic neurons is poorly understood. Preexisting spatially asymmetric cues, distributed within the neuron or as extracellular gradients, could be required for neurons to polarize. Alternatively, neurons might have the intrinsic ability to polarize without any preestablished asymmetric cues. In Caenorhabditis elegans, the UNC-40 (DCC) receptor mediates responses to the extracellular UNC-6 (netrin) guidance cue. For the HSN neuron, an UNC-6 ventral-dorsal gradient asymmetrically localizes UNC-40 to the ventral HSN surface. There an axon forms, which is ventrally directed by UNC-6. In the absence of UNC-6, UNC-40 is equally distributed and the HSN axon travels anteriorly in response to other cues. However, we find that a single amino acid change in the UNC-40 ectodomain causes randomly oriented asymmetric UNC-40 localization and a wandering axon phenotype. With UNC-6, there is normal UNC-40 localization and axon migration. A single UNC-6 amino acid substitution enhances the mutant phenotypes, whereas UNC-6 second-site amino acid substitutions suppress the phenotypes. We propose that UNC-40 mediates multiple signals to polarize and orient asymmetry. One signal triggers the intrinsic ability of HSN to polarize and causes randomly oriented asymmetry. Concurrently, another signal biases the orientation of the asymmetry relative to the UNC-6 gradient. The UNC-40 ectodomain mutation activates the polarization signal, whereas different forms of the UNC-6 ligand produce UNC-40 conformational changes that allow or prohibit the orientation signal.
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95
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6-Amino-4-oxo-1,3-diphenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonyl derivatives as a new class of potent inhibitors of Interleukin-8-induced neutrophil chemotaxis. Bioorg Med Chem 2009; 17:3580-7. [DOI: 10.1016/j.bmc.2009.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 04/02/2009] [Accepted: 04/06/2009] [Indexed: 12/16/2022]
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96
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The type III TGF-beta receptor regulates epithelial and cancer cell migration through beta-arrestin2-mediated activation of Cdc42. Proc Natl Acad Sci U S A 2009; 106:8221-6. [PMID: 19416857 DOI: 10.1073/pnas.0812879106] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Loss of expression of the TGF-beta superfamily coreceptor, the type III TGF-beta receptor (TbetaRIII or betaglycan), occurs in a broad spectrum of human cancers including breast, lung, ovarian, pancreatic, prostate, and renal cell cancer. TbetaRIII suppresses cancer progression in vivo, at least in part, by reducing cancer cell motility. However, the mechanism by which TbetaRIII regulates migration is unknown. Here, we demonstrate an unexpected TGF-beta signaling independent role for TbetaRIII in activating Cdc42, altering the actin cytoskeleton and reducing directional persistence to inhibit random migration of both cancer and normal epithelial cells. Functionally, TbetaRIII through its interaction with the scaffolding protein beta-arrestin2, activates Cdc42 and inhibits migration. These studies identify a TGF-beta independent homeostatic function for TbetaRIII in regulating cell migration.
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97
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Miller DS, Chirayil S, Ball HL, Luebke KJ. Manipulating cell migration and proliferation with a light-activated polypeptide. Chembiochem 2009; 10:577-84. [PMID: 19165838 DOI: 10.1002/cbic.200800679] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Remote control of cells: A polypeptide has been made that stimulates proliferation and migration of cells upon photochemical activation. This light-activated polypeptide enables spatially defined control of cell populations at the scale of tissue organization; this is accomplished without physically contacting the cells or modifying their substrate. Polypeptide growth and differentiation factors modulate a wide variety of cell behaviors and can be used to manipulate cells in vitro for tissue engineering and basic studies of cell biology. To emulate in vitro the spatial aspect of growth factor function, new methods are needed to generate defined spatial gradients of activity. Polypeptide factors that are engineered to be activated with light provide a method for creating concentration gradients with the fine precision in space and time with which light can be directed. As a first test of this approach, we have chemically synthesized a polypeptide with the sequence of epidermal growth factor in which a critical glutamate is "caged" with a photoremovable group. Photolysis of this polypeptide afforded maximal mitogenic and chemokinetic activity at concentrations at which the caged factor was inactive. Spatially resolved photolysis of the factor resulted in spatial patterning of fibroblasts. This system will be useful for ex vivo tissue engineering and for investigating the interactions of cells with their matrix and the role of chemical gradients in biological pattern formation.
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Affiliation(s)
- Danielle S Miller
- Division of Translational Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9185, USA
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98
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Damann N, Owsianik G, Li S, Poll C, Nilius B. The calcium-conducting ion channel transient receptor potential canonical 6 is involved in macrophage inflammatory protein-2-induced migration of mouse neutrophils. Acta Physiol (Oxf) 2009; 195:3-11. [PMID: 18983454 DOI: 10.1111/j.1748-1716.2008.01918.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
AIM The role of the calcium-conducting ion channel transient receptor potential canonical 6 (TRPC6) in macrophage inflammatory protein-2 (MIP-2) induced migration of mouse neutrophils was investigated. METHODS Neutrophil granulocytes isolated from murine bone marrow of wild-type (TRPC6+/+) and TRPC6 knockout (TRPC6)/)) mice were tested for the presence of TRPC6 channel expression using quantitative real-time polymerase chain reactions and immunocytochemistry. The effect of different stimuli (e.g. MIP-2, 1-oleoyl-2-acetyl-sn-glycerol, formyl-methionyl-leucyl-phenylalanin) on migration of isolated neutrophils was tested by two-dimensional (2D) migration assays, phalloidin staining and intracellular calcium imaging. RESULTS We found that neutrophil granulocytes express TRPC6 channels. MIP-2 induced fast cell migration of isolated neutrophils in a 2D celltracking system. Strikingly, MIP-2 was less potent in neutrophils derived from TRPC6)/) mice. These cells showed less phalloidin-coupled fluorescence and the pattern of cytosolic calcium transients was altered. CONCLUSIONS We describe in this paper for the first time a role for transient receptor potential (TRP) channels in migration of native lymphocytes as a new paradigm for the universal functional role of TRPs. Our data give strong evidence that TRPC6 operates downstream to CXC-type Gq-protein-coupled chemokine receptors upon stimulation with MIP-2 and is crucial for the arrangement of filamentous actin in migrating neutrophils. This is a novel cell function of TRP channel beyond their well-recognized role as universal cell sensors.
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Affiliation(s)
- N Damann
- Department of Molecular Cell Biology, Laboratory of Ion Channel Research, KU Leuven, Leuven, Belgium
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99
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Gassama-Diagne A, Payrastre B. Phosphoinositide signaling pathways: promising role as builders of epithelial cell polarity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 273:313-43. [PMID: 19215908 DOI: 10.1016/s1937-6448(08)01808-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Polarity is a prerequisite for proper development and function of epithelia in metazoa. The major feature of polarized epithelial cells is the presence of specialized domains with asymmetric distribution of macromolecular contents including proteins and lipids. The apical domain is involved in exchange with the organ lumen, and the basolateral membrane maintains contact with neighboring cells and the underlying extracellular matrix. The two domains are separated by tight junctions, which act as a diffusion barrier to prevent free mixing of domain-specific proteins and lipids. Extensive studies have shed light on the numerous protein families involved in cell polarization. However, many questions still remain regarding the molecular mechanisms of polarity regulation and in particular very little is known about the role of lipids in building polarity. In this chapter, essential determinants of epithelial polarity will be reviewed with a particular focus on metabolism and function of phosphoinositides.
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Affiliation(s)
- Ama Gassama-Diagne
- Unité Mixte INSERM U785/Université Paris XI, Centre Hépatobiliaire, Hôpital Paul Brousse, Villejuif, France
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100
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Maeda YT, Inose J, Matsuo MY, Iwaya S, Sano M. Ordered patterns of cell shape and orientational correlation during spontaneous cell migration. PLoS One 2008; 3:e3734. [PMID: 19011688 PMCID: PMC2581918 DOI: 10.1371/journal.pone.0003734] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 10/27/2008] [Indexed: 12/27/2022] Open
Abstract
Background In the absence of stimuli, most motile eukaryotic cells move by
spontaneously coordinating cell deformation with cell movement in the
absence of stimuli. Yet little is known about how cells change their own
shape and how cells coordinate the deformation and movement. Here, we
investigated the mechanism of spontaneous cell migration by using
computational analyses. Methodology We observed spontaneously migrating Dictyostelium cells
in both a vegetative state (round cell shape and slow motion) and
starved one (elongated cell shape and fast motion). We then extracted
regular patterns of morphological dynamics and the pattern-dependent
systematic coordination with filamentous actin (F-actin) and cell
movement by statistical dynamic analyses. Conclusions/Significance We found that Dictyostelium cells in both vegetative and
starved states commonly organize their own shape into three ordered
patterns, elongation, rotation, and oscillation, in the absence of
external stimuli. Further, cells inactivated for PI3-kinase (PI3K)
and/or PTEN did not show ordered patterns due to the lack of spatial
control in pseudopodial formation in both the vegetative and starved
states. We also found that spontaneous polarization was achieved in
starved cells by asymmetric localization of PTEN and F-actin. This
breaking of the symmetry of protein localization maintained the leading
edge and considerably enhanced the persistence of directed migration,
and overall random exploration was ensured by switching among the
different ordered patterns. Our findings suggest that
Dictyostelium cells spontaneously create the
ordered patterns of cell shape mediated by PI3K/PTEN/F-actin and control
the direction of cell movement by coordination with these patterns even
in the absence of external stimuli.
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Affiliation(s)
- Yusuke T Maeda
- Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
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