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Francis CR, Bell ML, Skripnichuk MM, Kushner EJ. Arf6 is required for endocytosis and filamentous actin assembly during angiogenesis in vitro. Microcirculation 2023; 30:e12831. [PMID: 37750425 PMCID: PMC10688150 DOI: 10.1111/micc.12831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/24/2023] [Accepted: 09/13/2023] [Indexed: 09/27/2023]
Abstract
OBJECTIVE Endocytosis is a process vital to angiogenesis and vascular homeostasis. In pathologies where supraphysiological growth factor signaling underlies disease etiology, such as in diabetic retinopathy and solid tumors, strategies to limit chronic growth factor signaling by way of blunting endocytic processes have been shown to have tremendous clinical value. ADP ribosylation factor 6 (Arf6) is a small GTPase that promotes the assembly of actin necessary for clathrin-mediated and clathrin-independent endocytosis. In its absence, growth factor signaling is greatly diminished, which has been shown to ameliorate pathological signaling input in diseased vasculature. However, it is less clear if there are bystander effects related to loss of Arf6 on angiogenic behaviors. Our goal was to provide an analysis of Arf6's function in angiogenic endothelium, focusing on its role in actin and endocytosis as well as sprouting morphogenesis. METHODS Primary endothelial cells were cultured in both 2D and 3D environments. Here, endothelial cells were fixed and stained for various proteins or transfected with fluorescently-tagged constructs for live-cell imaging. RESULTS We found that Arf6 localized to both filamentous actin and sites of endocytosis in two-dimensional culture. Loss of Arf6 distorted both apicobasal polarity and reduced the total cellular filamentous actin content, which may be the primary driver underlying gross sprouting dysmorphogenesis in its absence. CONCLUSIONS Our findings highlight that endothelial Arf6 is a potent mediator of both actin regulation and endocytosis and is required for proper sprout formation.
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Affiliation(s)
| | - Makenzie L. Bell
- Department of Biological Sciences, University of Denver, Denver, CO
| | | | - Erich J. Kushner
- Department of Biological Sciences, University of Denver, Denver, CO
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Abstract
Clathrin-mediated endocytosis (CME) is a process vital to angiogenesis as well as general vascular homeostasis. In pathologies where supraphysiological growth factor signaling underlies disease etiology, such as in diabetic retinopathy and solid tumors, strategies to limit chronic growth factor signaling by way of CME have been shown to have tremendous clinical value. ADP ribosylation factor 6 (Arf6) is a small GTPase that promotes the assembly of actin necessary for CME. In its absence, growth factor signaling is greatly diminished, which has been shown to ameliorate pathological signaling input in diseased vasculature. However, it is less clear if there are bystander effects related to loss of Arf6 on angiogenic behaviors. Our goal was to provide a analysis of Arf6’s function in angiogenic endothelium, focusing on its role in lumenogenesis as well as its relation to actin and CME. We found that Arf6 localized to both filamentous actin and sites of CME in 2-dimensional culture. Loss of Arf6 distorted both apicobasal polarity and reduced the total cellular filamentous actin content, and this may be the primary driver underlying gross dysmorphogenesis during angiogenic sprouting in its absence. Our findings highlight that endothelial Arf6 is a potent mediator of both actin regulation and CME.
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Affiliation(s)
| | - Makenzie L. Bell
- Department of Biological Sciences, University of Denver, Denver, CO
| | | | - Erich J. Kushner
- Department of Biological Sciences, University of Denver, Denver, CO
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Partisani M, Baron CL, Ghossoub R, Fayad R, Pagnotta S, Abélanet S, Macia E, Brau F, Lacas-Gervais S, Benmerah A, Luton F, Franco M. EFA6A, an exchange factor for Arf6, regulates early steps in ciliogenesis. J Cell Sci 2021; 134:237326. [PMID: 33483367 DOI: 10.1242/jcs.249565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022] Open
Abstract
Ciliogenesis is a coordinated process initiated by the recruitment and fusion of pre-ciliary vesicles at the distal appendages of the mother centriole through mechanisms that remain unclear. Here, we report that EFA6A (also known as PSD), an exchange factor for the small G protein Arf6, is involved in early stage of ciliogenesis by promoting the fusion of distal appendage vesicles forming the ciliary vesicle. EFA6A is present in the vicinity of the mother centriole before primary cilium assembly and prior to the arrival of Arl13B-containing vesicles. During ciliogenesis, EFA6A initially accumulates at the mother centriole and later colocalizes with Arl13B along the ciliary membrane. EFA6A depletion leads to the inhibition of ciliogenesis, the absence of centrosomal Rab8-positive structures and the accumulation of Arl13B-positive vesicles around the distal appendages. Our results uncover a novel fusion machinery, comprising EFA6A, Arf6 and Arl13B, that controls the coordinated fusion of ciliary vesicles docked at the distal appendages of the mother centriole.
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Affiliation(s)
- Mariagrazia Partisani
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
| | - Carole L Baron
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
| | - Rania Ghossoub
- Centre de Recherche en Cancérologie de Marseille (CRCM), Inserm, U1068-CNRS UMR7258, Aix-Marseille Université, Institut Paoli-Calmettes, 13009 Marseille, France
| | - Racha Fayad
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
| | - Sophie Pagnotta
- Centre Commun de Microscopie Appliquée (CCMA), Université Côte d'Azur Parc Valrose, 06103 Nice cedex 2, France
| | - Sophie Abélanet
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
| | - Eric Macia
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
| | - Frédéric Brau
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
| | - Sandra Lacas-Gervais
- Centre Commun de Microscopie Appliquée (CCMA), Université Côte d'Azur Parc Valrose, 06103 Nice cedex 2, France
| | - Alexandre Benmerah
- Université de Paris, Imagine Institute, Laboratory of Inherited Kidney Diseases, INSERM UMR 1163, F-75015, Paris, France
| | - Frédéric Luton
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
| | - Michel Franco
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275 CNRS-Université Côte d'Azur, 660, route des lucioles, 06560 Valbonne, France
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Rozés-Salvador V, González-Billault C, Conde C. The Recycling Endosome in Nerve Cell Development: One Rab to Rule Them All? Front Cell Dev Biol 2020; 8:603794. [PMID: 33425908 PMCID: PMC7793921 DOI: 10.3389/fcell.2020.603794] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 09/07/2020] [Accepted: 11/11/2020] [Indexed: 12/13/2022] Open
Abstract
Endocytic recycling is an intracellular process that returns internalized molecules back to the plasma membrane and plays crucial roles not only in the reuse of receptor molecules but also in the remodeling of the different components of this membrane. This process is required for a diversity of cellular events, including neuronal morphology acquisition and functional regulation, among others. The recycling endosome (RE) is a key vesicular component involved in endocytic recycling. Recycling back to the cell surface may occur with the participation of several different Rab proteins, which are master regulators of membrane/protein trafficking in nerve cells. The RE consists of a network of interconnected and functionally distinct tubular subdomains that originate from sorting endosomes and transport their cargoes along microtubule tracks, by fast or slow recycling pathways. Different populations of REs, particularly those formed by Rab11, Rab35, and Arf6, are associated with a myriad of signaling proteins. In this review, we discuss the cumulative evidence suggesting the existence of heterogeneous domains of REs, controlling different aspects of neurogenesis, with a particular focus on the commonalities and singularities of these REs and their contribution to nerve development and differentiation in several animal models.
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Affiliation(s)
- Victoria Rozés-Salvador
- Instituto de Investigación Médica Mercedes y Martín Ferreyra INIMEC-CONICET-UNC, Córdoba, Argentina.,Instituto de Ciencias Básicas, Universidad Nacional de Villa María, Córdoba, Argentina
| | - Christian González-Billault
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile.,Department of Neurosciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism, Santiago, Chile.,The Buck Institute for Research on Aging, Novato, CA, United States
| | - Cecilia Conde
- Instituto de Investigación Médica Mercedes y Martín Ferreyra INIMEC-CONICET-UNC, Córdoba, Argentina
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