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Goudreault M, Gagné V, Jo CH, Singh S, Killoran RC, Gingras AC, Smith MJ. Afadin couples RAS GTPases to the polarity rheostat Scribble. Nat Commun 2022; 13:4562. [PMID: 35931706 PMCID: PMC9355967 DOI: 10.1038/s41467-022-32335-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 07/26/2022] [Indexed: 11/10/2022] Open
Abstract
AFDN/Afadin is required for establishment and maintenance of cell-cell contacts and is a unique effector of RAS GTPases. The biological consequences of RAS complex with AFDN are unknown. We used proximity-based proteomics to generate an interaction map for two isoforms of AFDN, identifying the polarity protein SCRIB/Scribble as the top hit. We reveal that the first PDZ domain of SCRIB and the AFDN FHA domain mediate a direct but non-canonical interaction between these important adhesion and polarity proteins. Further, the dual RA domains of AFDN have broad specificity for RAS and RAP GTPases, and KRAS co-localizes with AFDN and promotes AFDN-SCRIB complex formation. Knockout of AFDN or SCRIB in epithelial cells disrupts MAPK and PI3K activation kinetics and inhibits motility in a growth factor-dependent manner. These data have important implications for understanding why cells with activated RAS have reduced cell contacts and polarity defects and implicate AFDN as a genuine RAS effector. Goudreault et al. investigate the role of Afadin downstream of RAS GTPases, substantiating this cell adhesion protein as a true RAS effector that couples its activation to cell polarity through the Scribble protein.
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Affiliation(s)
- Marilyn Goudreault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Valérie Gagné
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Chang Hwa Jo
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Swati Singh
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Ryan C Killoran
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G 1X5, Canada
| | - Matthew J Smith
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada. .,Department of Pathology and Cell Biology, Faculty of Medicine, Université de Montréal, Montréal, QC, H3T 1J4, Canada.
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2
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Nectins and Nectin-like molecules in synapse formation and involvement in neurological diseases. Mol Cell Neurosci 2021; 115:103653. [PMID: 34242750 DOI: 10.1016/j.mcn.2021.103653] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 05/11/2021] [Accepted: 06/25/2021] [Indexed: 12/12/2022] Open
Abstract
Synapses are interneuronal junctions which form neuronal networks and play roles in a variety of functions, including learning and memory. Two types of junctions, synaptic junctions (SJs) and puncta adherentia junctions (PAJs), have been identified. SJs are found at all excitatory and inhibitory synapses whereas PAJs are found at excitatory synapses, but not inhibitory synapses, and particularly well developed at hippocampal mossy fiber giant excitatory synapses. Both SJs and PAJs are mediated by cell adhesion molecules (CAMs). Major CAMs at SJs are neuroligins-neurexins and Nectin-like molecules (Necls)/CADMs/SynCAMs whereas those at PAJs are nectins and cadherins. In addition to synaptic PAJs, extrasynaptic PAJs have been identified at contact sites between neighboring dendrites near synapses and regulate synapse formation. In addition to SJs and PAJs, a new type of cell adhesion apparatus different from these junctional apparatuses has been identified and named nectin/Necl spots. One nectin spot at contact sites between neighboring dendrites at extrasynaptic regions near synapses regulates synapse formation. Several members of nectins and Necls had been identified as viral receptors before finding their physiological functions as CAMs and evidence is accumulating that many nectins and Necls are related to onset and progression of neurological diseases. We review here nectin and Necls in synapse formation and involvement in neurological diseases.
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Huxham J, Tabariès S, Siegel PM. Afadin (AF6) in cancer progression: A multidomain scaffold protein with complex and contradictory roles. Bioessays 2020; 43:e2000221. [PMID: 33165933 DOI: 10.1002/bies.202000221] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/17/2020] [Accepted: 09/24/2020] [Indexed: 11/09/2022]
Abstract
Adherens (AJ) and tight junctions (TJ) maintain cell-cell adhesions and cellular polarity in normal tissues. Afadin, a multi-domain scaffold protein, is commonly found in both adherens and tight junctions, where it plays both structural and signal-modulating roles. Afadin is a complex modulator of cellular processes implicated in cancer progression, including signal transduction, migration, invasion, and apoptosis. In keeping with the complexities associated with the roles of adherens and tight junctions in cancer, afadin exhibits both tumor suppressive and pro-metastatic functions. In this review, we will explore the dichotomous roles that afadin plays during cancer progression.
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Affiliation(s)
- Jennifer Huxham
- Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada.,Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Sébastien Tabariès
- Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada.,Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Peter M Siegel
- Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada.,Department of Medicine, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, McGill University, Montréal, Québec, Canada.,Department of Anatomy & Cell Biology, McGill University, Montréal, Québec, Canada.,Department of Oncology, McGill University, Montréal, Québec, Canada
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Matsuda T, Namura A, Oinuma I. Dynamic spatiotemporal patterns of alternative splicing of an F-actin scaffold protein, afadin, during murine development. Gene 2019; 689:56-68. [PMID: 30572094 DOI: 10.1016/j.gene.2018.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/23/2018] [Accepted: 12/12/2018] [Indexed: 12/17/2022]
Abstract
An F-actin scaffold protein, afadin, comprises two splice variants called l-afadin (a long isoform) and s-afadin (a short isoform). It is known that in adult tissues, l-afadin is ubiquitously expressed while s-afadin is restrictedly expressed in brain. In cultured cortical neurons, l-afadin potentiates axonal branching whereas s-afadin blocks axonal branching by functioning as a naturally occurring dominant-negative isoform that forms a heterodimer with l-afadin. However, the temporal and spatial expression pattern of s-afadin during development or across multiple tissues and organs has not been fully understood. In this study, using Western blotting and RT-qPCR techniques and the fluorescent splicing reporters, we examined the detailed expression patterns of l- and s-afadin isoforms across various tissues and cell types, including rat organs at developmental stages, primary cultured neuronal and non-neuronal cells prepared from the developing rat brain, and in neurons in vitro generated from P19 embryonal carcinoma (EC) cells. Both mRNA and protein of s-afadin were abundantly expressed in various regions of rat neuronal tissues, and their expression dynamically changed during development in vivo. The expression of s-afadin was also detected in primary rat cortical neurons, but not in astrocytes or fibroblasts, and the neuronal expression increased during neuronal maturation in vitro. The dynamic alternative splicing event of afadin during development was successfully visualized with the newly developed fluorescent splicing reporter plasmids at a single cell level. Moreover, s-afadin was undetectable in undifferentiated EC cells, and the expression was induced upon differentiation of the cells into neurons. These data suggest that spatiotemporal and dynamic alternative splicing produces differential expression patterns of afadin isoforms and that alternative splicing of afadin is controlled by the neuron-specific regulator(s) whose activity is triggered and dynamically altered during neuronal differentiation and maturation.
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Affiliation(s)
- Takahiko Matsuda
- Laboratory of Cell and Molecular Biology, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Arisa Namura
- Laboratory of Cell and Molecular Biology, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Izumi Oinuma
- Laboratory of Cell and Molecular Biology, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan; Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
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Differential regional and subcellular localization patterns of afadin splice variants in the mouse central nervous system. Brain Res 2018; 1692:74-86. [PMID: 29733813 DOI: 10.1016/j.brainres.2018.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 04/29/2018] [Accepted: 05/03/2018] [Indexed: 12/15/2022]
Abstract
AF6/afadin is an F-actin scaffold protein that plays essential roles in the organization of cell-cell junctions of polarized epithelia. Afadin comprises two major isoforms produced by alternative splicing - a longer isoform l-afadin, having the F-actin-binding domain, and a shorter isoform s-afadin, harboring the amino acid sequences unique to the isoform but lacking the F-actin-binding domain. We recently identified functional differences between l- and s-afadin isoforms in the regulation of axon branching in primary cultured cortical neurons; the former potentiates and the latter blocks axon branching. Previous biochemical reports indicate differences in tissue and cell-type distributions of isoforms, and it was shown that l-afadin is ubiquitously expressed in various tissues and cell-types, while s-afadin is predominantly expressed in neuronal tissues and cultured neurons. However, the spatial expression pattern of s-afadin across neuronal tissues or within neurons has not been revealed because no antibody specific for s-afadin is yet available. In this study, we report the generation and characterization of an antibody that specifically distinguishes s-afadin from l-afadin, and its application to investigate the expression profile of s-afadin in primary cultured neurons and tissue cryosections of adult mouse brain and retina. We describe differential regional and subcellular localization patterns of l- and s-afadin isoforms in the mouse central nervous system.
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Poon CE, Madawala RJ, Dowland SN, Murphy CR. Nectin-3 Is Increased in the Cell Junctions of the Uterine Epithelium at Implantation. Reprod Sci 2016; 23:1580-1592. [DOI: 10.1177/1933719116648216] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Connie E. Poon
- Cell and Reproductive Biology Laboratory, School of Medical Sciences (Discipline of Anatomy and Histology), The University of Sydney, Sydney, New South Wales, Australia
- The Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Romanthi J. Madawala
- Cell and Reproductive Biology Laboratory, School of Medical Sciences (Discipline of Anatomy and Histology), The University of Sydney, Sydney, New South Wales, Australia
- The Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Samson N. Dowland
- Cell and Reproductive Biology Laboratory, School of Medical Sciences (Discipline of Anatomy and Histology), The University of Sydney, Sydney, New South Wales, Australia
- The Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Christopher R. Murphy
- Cell and Reproductive Biology Laboratory, School of Medical Sciences (Discipline of Anatomy and Histology), The University of Sydney, Sydney, New South Wales, Australia
- The Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia
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Miyata M, Mandai K, Maruo T, Sato J, Shiotani H, Kaito A, Itoh Y, Wang S, Fujiwara T, Mizoguchi A, Takai Y, Rikitake Y. Localization of nectin-2δ at perivascular astrocytic endfoot processes and degeneration of astrocytes and neurons in nectin-2 knockout mouse brain. Brain Res 2016; 1649:90-101. [PMID: 27545667 DOI: 10.1016/j.brainres.2016.08.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 08/09/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
Abstract
Nectins are Ca2+-independent immunoglobulin-like cell-cell adhesion molecules. In the nervous system, among four members (nectin-1, -2, -3, and -4), nectin-1 and -3 are asymmetrically localized at puncta adherentia junctions formed between the mossy fiber terminals and the dendrites of CA3 pyramidal neurons in the mouse hippocampus and heterophilic trans-interactions between nectin-1 and nectin-3 are involved in the selective interaction of axons and dendrites of cultured neurons. By contrast, nectin-2, which has two splicing variants, nectin-2α and -2δ, has not been well characterized in the brain. We showed here that nectin-2α was expressed in both cultured mouse neurons and astrocytes whereas nectin-2δ was selectively expressed in the astrocytes. Nectin-2δ was localized at the adhesion sites between adjacent cultured astrocytes, but in the brain it was localized on the plasma membranes of astrocytic perivascular endfoot processes facing the basement membrane of blood vessels. Genetic ablation of nectin-2 caused degeneration of astrocytic perivascular endfoot processes and neurons in the cerebral cortex. These results uncovered for the first time the localization and critical functions of nectin-2 in the brain.
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Affiliation(s)
- Muneaki Miyata
- Division of Signal Transduction, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
| | - Kenji Mandai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan
| | - Tomohiko Maruo
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan
| | - Junya Sato
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Hajime Shiotani
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; Department of Neurology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Aika Kaito
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Yu Itoh
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Shujie Wang
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Takeshi Fujiwara
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Akira Mizoguchi
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan.
| | - Yoshiyuki Rikitake
- Division of Signal Transduction, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe 658-8558, Japan.
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Carminati M, Gallini S, Pirovano L, Alfieri A, Bisi S, Mapelli M. Concomitant binding of Afadin to LGN and F-actin directs planar spindle orientation. Nat Struct Mol Biol 2016; 23:155-63. [DOI: 10.1038/nsmb.3152] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 11/26/2015] [Indexed: 12/19/2022]
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Umeda K, Iwasawa N, Negishi M, Oinuma I. A short splicing isoform of afadin suppresses the cortical axon branching in a dominant-negative manner. Mol Biol Cell 2015; 26:1957-70. [PMID: 25808489 PMCID: PMC4436838 DOI: 10.1091/mbc.e15-01-0039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/18/2015] [Indexed: 01/11/2023] Open
Abstract
Suppression of surplus axon branching is crucial for formation of proper neuronal networks; however, the molecular mechanisms have been poorly understood. In a novel mechanism, s-afadin, a short splicing isoform of afadin lacking the F-actin–binding domain, acts as a dominant-negative suppressor of cortical axon branching. Precise wiring patterns of axons are among the remarkable features of neuronal circuit formation, and establishment of the proper neuronal network requires control of outgrowth, branching, and guidance of axons. R-Ras is a Ras-family small GTPase that has essential roles in multiple phases of axonal development. We recently identified afadin, an F-actin–binding protein, as an effector of R-Ras mediating axon branching through F-actin reorganization. Afadin comprises two isoforms—l-afadin, having the F-actin–binding domain, and s-afadin, lacking the F-actin–binding domain. Compared with l-afadin, s-afadin, the short splicing variant of l-afadin, contains RA domains but lacks the F-actin–binding domain. Neurons express both isoforms; however, the function of s-afadin in brain remains unknown. Here we identify s-afadin as an endogenous inhibitor of cortical axon branching. In contrast to the abundant and constant expression of l-afadin throughout neuronal development, the expression of s-afadin is relatively low when cortical axons branch actively. Ectopic expression and knockdown of s-afadin suppress and promote branching, respectively. s-Afadin blocks the R-Ras–mediated membrane translocation of l-afadin and axon branching by inhibiting the binding of l-afadin to R-Ras. Thus s-afadin acts as a dominant-negative isoform in R-Ras-afadin–regulated axon branching.
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Affiliation(s)
- Kentaro Umeda
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Nariaki Iwasawa
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Manabu Negishi
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Izumi Oinuma
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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