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The role of specific membrane microdomain components (flotillins) in signaling, cytoskeletal reorganization, adhesion and migration of leukocytes and tumor cells

Applicant Niggli Sigel Verena
Number 129655
Funding scheme Project funding (Div. I-III)
Research institution Institut für Pathologie Medizinische Fakultät Universität Bern
Institution of higher education University of Berne - BE
Main discipline Cellular Biology, Cytology
Start/End 01.05.2010 - 30.04.2013
Approved amount 238'920.00
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Keywords (13)

cell migration; chemotaxis; cell adhesion; cell polarization; membrane microdomain; flotillin; neutrophil granulocyte; T-lymphocyte; HT1080 fibrosarcoma cell; Inflammation; metastasis; leukocyte; tumor cell

Lay Summary (English)

Lead
Lay summary
Lead: Cell migration is crucial for example for elimination of bacteria during inflammation and plays also an important role in tumor metastasis. A better understanding of the molecular mechanisms of cell migration is crucial for the development of novel therapeutic strategies to counteract inflammation and metastasis.Background: Upon infection of tissue with for example bacteria, white blood cells (leukocytes) leave the blood vessel and migrate to the source of infection, where they destroy the invading bacteria. The capacity to migrate is also an important factor contributing to the spread of tumor cells in the body in order to form metastases. The cytoskeleton, an intracellular network of structural proteins, is crucially involved in cell migration. The cytoskeleton is controlled by a complex signaling system. Polarized migrating leukocytes contain membrane microdomains of different composition in the leading edge and in the rear. We observed enrichment of specific microdomain-associated proteins in the rear of polarized leukocytes. Plasma membrane microdomains represent a central feature of cellular organization which could be crucial for the local activation of specific signaling cascades. Their composition, dynamics and role in migration of diverse cell types has not yet been adequately studied.Aim: Our research efforts are concentrated on the following points: elucidation of the composition of plasma membrane microdomains in specific areas of migrating leukocytes and tumor cells; analysis of the dynamics of individual components during migration; analysis of interactions of these components in resting and stimulated cells; dissection of the roles of the individual components in (directed) migration of leukocytes and tumor cells.Significance: We expect that the obtained knowledge provides novel information on the role of plasma membrane microdomains in regulating signalling, cytoskeletal reorganization, polarization, adhesion and migration in leukocytes and tumor cell lines. This should be important for our understanding of the mechanisms of neutrophil and tumor cell motility, processes involved in inflammation and metastasis and may lead to the development of novel therapeutic strategies.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Ezrin/radixin/moesin proteins and flotillins cooperate to promote uropod formation in T cells.
Martinelli Sibylla, Chen Emily .J.H., Clarke Fiona, Lyck Ruth, Affentranger Sarah, Burkhardt Janis K. (2013), Ezrin/radixin/moesin proteins and flotillins cooperate to promote uropod formation in T cells., in Frontiers in Immunology, 4, 84.
Evidence for chemokine-mediated coalescence of preformed flotillin heterooligomers in human T-cells.
Baumann Tommy, Affentranger Sarah, Niggli Verena (2012), Evidence for chemokine-mediated coalescence of preformed flotillin heterooligomers in human T-cells., in Journal of Biological Chemistry, 287, 39664-39672.
Enhanced activity of meprin-alpha, a pro-migratory and pro-angiogenic protease, in colorectal cancer.
Lottaz Daniel, Maurer Christoph A., Noel Agnes, Blacher Silvia, Huguenin Maya, Nievergelt Alexandra, Niggli Verena, Kern. Alexander, Müller Stefan, Seibold Frank, Friess Helmut, Becker-Pauly Christoph, Stöcker Walter, Sterchi Erwin E. (2011), Enhanced activity of meprin-alpha, a pro-migratory and pro-angiogenic protease, in colorectal cancer., in PLos One, 6(11), e26450.
Dynamic reorganization of flotillins in chemokine-stimulated human T-lymphocytes.
Affentranger Sarah, Martinelli Sibylla, Hahn Jonas, Rossy Jérémie, Niggli Verena (2011), Dynamic reorganization of flotillins in chemokine-stimulated human T-lymphocytes., in BMC Cell Biology, 12, 28.

Collaboration

Group / person Country
Types of collaboration
Research group of Prof. Anna Huttenlocher/University of Wisconsin United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Research group of Dr. Janis Burkhardt, University of Pennsylvania, Childrens Hospital of Philadelphi United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Gordon research Conference on Directed Cell Migration, 2013 20.01.2013 Galveston, Texas
7th Abercrombie Meeting, 2012 24.06.2012 Oxford, England
Gordon research Conference on gradient sensing and Directed Cell Migration, 2011 05.06.2011 les Diablerets, Switzerland


Self-organised

Title Date Place
Cytomeet 2013 29.01.2013 Bern, Switzerland
Cytomeet 2012 24.01.2012 Bern, Switzerland
Cytomeet 2011 25.01.2011 Bern, Switzerland

Associated projects

Number Title Start Funding scheme
103708 The role of lipid microdomains in signaling and cytoskeletal reorganization in migrating leukocytes and tumor cells 01.04.2004 Project funding (Div. I-III)

Abstract

1. Background: Directed cell locomotion is crucial for physiological processes such as embryonal development and host defense against pathogens and plays also an important role in pathological events such as neoplastic invasion. Localized signalling resulting in reorganization of the cytoskeleton, changes in cell shape and cell adhesion have been recognized to be crucial for cell locomotion. Many aspects of localized signalling are incompletely characterized. Membrane microdomains represent a central feature of cellular organization which could be crucial for the local activation of specific signalling cascades and adhesion molecules. Reggie/flotillin-1 and -2 are important microdomain-associated proteins whose functions in cell migration are as yet not well defined. 2. Working hypothesis: Polarized migrating leukocytes contain membrane microdomains of different composition in the leading edge and in the rear. We observed that capping of the microdomain-associated proteins flotillin-1 and -2 is a very early event during neutrophil polarization. Upon stimulation of cells these proteins are concentrated at the site of the later uropod. These novel findings suggest that flotillins play an important role in uropod formation and/or organization of adhesion receptors, cytoskeletal proteins and/or signalling molecules in the uropod. Depletion of flotillins should thus result in defects in migration and adhesion. 3. Specific aims: We plan to study the dynamic reorganization of flotillins in polarizing and migrating leukocytes and tumor cells, and the role of cytoskeletal and signalling proteins in these processes. We also will attempt to interfere with flotillin functions using small interfering RNA (siRNA) or dominant-negative mutants of flotillins. These experiments should lead to information on whether flotillin-1 and -2 are required for adhesion, polarization, migration and chemotaxis of leukocytes and tumor cells. The role of flotillin isoforms in uropod localization of cytoskeletal molecules and adhesion receptors and in regulating chemoattractant-mediated signalling pathways will be addressed. Using expression of tagged flotillins in leukocytes and co-immunoprecipitation we will moreover attempt to identify novel flotillin interaction partners. Expression of mutated flotillins will be used to obtain information on the roles of flotillin domains for scaffold formation, cell motility etc. Fluorescence resonance energy transfer (FRET) will be used to monitor scaffold protein interactions in intact cells.4. Methods: transient transfection of cells with tagged flotillin-2 and/or flotillin-1, and mutants of these proteins; siRNA-mediated depletion of flotillin-1 and -2 in HL-60 cells, lymphocytes, tumor cells; analysis of impact of depletion of flotillin isoforms on signalling, adhesion, polarization and random as well as directed migration of these cells; expression of tagged wild-type and mutated flotillins, co-immunoprecipitation using a tag-directed antibody and mass spectrometry analysis of precipitated proteins for identification of novel flotillin interaction partners; FRET.5. Expected value of the proposed project: We expect that the obtained knowledge provides novel information on the role of flotillin-rich membrane microdomains in regulating signalling, cytoskeletal reorganization, polarization, adhesion and migration in leukocytes and tumor cell lines. This should be important for our understanding of the mechanisms of neutrophil and tumor cell motility, processes involved in inflammation and metastasis.
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