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Megrelis L, El Ghoul E, Moalli F, Versapuech M, Cassim S, Ruef N, Stein JV, Mangeney M, Delon J. Fam65b Phosphorylation Relieves Tonic RhoA Inhibition During T Cell Migration. Front Immunol 2018; 9:2001. [PMID: 30254631 PMCID: PMC6141708 DOI: 10.3389/fimmu.2018.02001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 08/14/2018] [Indexed: 11/13/2022] Open
Abstract
We previously identified Fam65b as an atypical inhibitor of the small G protein RhoA. Using a conditional model of a Fam65b-deficient mouse, we first show that Fam65b restricts spontaneous RhoA activation in resting T lymphocytes and regulates intranodal T cell migration in vivo. We next aimed at understanding, at the molecular level, how the brake that Fam65b exerts on RhoA can be relieved upon signaling to allow RhoA activation. Here, we show that chemokine stimulation phosphorylates Fam65b in T lymphocytes. This post-translational modification decreases the affinity of Fam65b for RhoA and favors Fam65b shuttling from the plasma membrane to the cytosol. Functionally, we show that the degree of Fam65b phosphorylation controls some cytoskeletal alterations downstream active RhoA such as actin polymerization, as well as T cell migration in vitro. Altogether, our results show that Fam65b expression and phosphorylation can finely tune the amount of active RhoA in order to favor optimal T lymphocyte motility.
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Affiliation(s)
- Laura Megrelis
- Infection, Immunity, Inflammation, Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Elyas El Ghoul
- Infection, Immunity, Inflammation, Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Federica Moalli
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Margaux Versapuech
- Infection, Immunity, Inflammation, Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Shamir Cassim
- Infection, Immunity, Inflammation, Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Nora Ruef
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Jens V Stein
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Marianne Mangeney
- Infection, Immunity, Inflammation, Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jérôme Delon
- Infection, Immunity, Inflammation, Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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Froehlich J, Versapuech M, Megrelis L, Largeteau Q, Meunier S, Tanchot C, Bismuth G, Delon J, Mangeney M. FAM65B controls the proliferation of transformed and primary T cells. Oncotarget 2018; 7:63215-63225. [PMID: 27556504 PMCID: PMC5325358 DOI: 10.18632/oncotarget.11438] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/10/2016] [Indexed: 01/08/2023] Open
Abstract
Cell quiescence is controlled by regulated genome-encoded programs that actively express genes which are often down-regulated or inactivated in transformed cells. Among them is FoxO1, a transcription factor that imposes quiescence in several cell types, including T lymphocytes. In these cells, the FAM65B encoding gene is a major target of FOXO1. Here, we show that forced expression of FAM65B in transformed cells blocks their mitosis because of a defect of the mitotic spindle, leading to G2 cell cycle arrest and apoptosis. Upon cell proliferation arrest, FAM65B is engaged in a complex containing two proteins well known to be involved in cell proliferation i.e. the HDAC6 deacetylase and the 14.3.3 scaffolding protein. In primary T cells, FAM65B is down-regulated upon T cell receptor engagement, and maintaining its expression blocks their proliferation, establishing that the decrease of FAM65B expression is required for proliferation. Conversely, inhibiting FAM65B expression in naive T lymphocytes decreases their activation threshold. These results identify FAM65B as a potential new target for controlling proliferation of both transformed and normal cells.
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Affiliation(s)
- Jeanne Froehlich
- Inserm, Institut Cochin, Paris, France.,Cnrs, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Margaux Versapuech
- Inserm, Institut Cochin, Paris, France.,Cnrs, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Laura Megrelis
- Inserm, Institut Cochin, Paris, France.,Cnrs, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Quitterie Largeteau
- Inserm, Institut Cochin, Paris, France.,Cnrs, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sylvain Meunier
- Inserm, PARCC, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Corinne Tanchot
- Inserm, PARCC, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Georges Bismuth
- Inserm, Institut Cochin, Paris, France.,Cnrs, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jérôme Delon
- Inserm, Institut Cochin, Paris, France.,Cnrs, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marianne Mangeney
- Inserm, Institut Cochin, Paris, France.,Cnrs, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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3
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Abstract
Cells respond to chemokine stimulation by losing their round shape in a process called polarization, and by altering the subcellular localization of many proteins. Classic imaging techniques have been used to study these phenomena. However, they required the manual acquisition of many cells followed by time consuming quantification of the morphology and the co-localization of the staining of tens of cells. Here, a rapid and powerful method is described to study these phenomena on samples consisting of several thousands of cells using an imaging flow cytometry technology that combines the advantages of a microscope with those of a cytometer. Using T lymphocytes stimulated with CCL19 and staining for MHC Class I molecules and filamentous actin, a gating strategy is presented to measure simultaneously the degree of shape alterations and the extent of co-localization of markers that are affected by CCL19 signaling. Moreover, this gating strategy allowed us to observe the segregation of filamentous actin (at the front) and phosphorylated Ezrin-Radixin-Moesin (phospho-ERM) proteins (at the rear) in polarized T cells after CXCL12 stimulation. This technique was also useful to observe the blocking effect on polarization of two different elements: inhibition of actin polymerization by a pharmacological inhibitor and expression of mutants of the Par6/atypical PKC signaling pathway. Thus, evidence is shown that this technique is useful to analyze both morphological alterations and protein redistributions.
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Affiliation(s)
- Laura Megrelis
- Inserm U1016, Institut Cochin; Cnrs, UMR8104; Université Paris Descartes, Sorbonne Paris Cité
| | - Jérôme Delon
- Inserm U1016, Institut Cochin; Cnrs, UMR8104; Université Paris Descartes, Sorbonne Paris Cité;
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Rougerie P, Largeteau Q, Megrelis L, Carrette F, Lejeune T, Toffali L, Rossi B, Zeghouf M, Cherfils J, Constantin G, Laudanna C, Bismuth G, Mangeney M, Delon J. Fam65b is a new transcriptional target of FOXO1 that regulates RhoA signaling for T lymphocyte migration. J Immunol 2012; 190:748-55. [PMID: 23241886 DOI: 10.4049/jimmunol.1201174] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Forkhead box O (FOXO) transcription factors favor both T cell quiescence and trafficking through their control of the expression of genes involved in cell cycle progression, adhesion, and homing. In this article, we report that the product of the fam65b gene is a new transcriptional target of FOXO1 that regulates RhoA activity. We show that family with sequence similarity 65 member b (Fam65b) binds the small GTPase RhoA via a noncanonical domain and represses its activity by decreasing its GTP loading. As a consequence, Fam65b negatively regulates chemokine-induced responses, such as adhesion, morphological polarization, and migration. These results show the existence of a new functional link between FOXO1 and RhoA pathways, through which the FOXO1 target Fam65b tonically dampens chemokine-induced migration by repressing RhoA activity.
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