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Mallik B, Pippadpally S, Bisht A, Bhat S, Mukherjee S, Kumar V. Distinct Bin/Amphiphysin/Rvs (BAR) family proteins may assemble on the same tubule to regulate membrane organization in vivo. Heliyon 2024; 10:e33672. [PMID: 39040266 PMCID: PMC11261073 DOI: 10.1016/j.heliyon.2024.e33672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 06/22/2024] [Accepted: 06/25/2024] [Indexed: 07/24/2024] Open
Abstract
Intracellular membrane tubules play a crucial role in diverse cellular processes, and their regulation is facilitated by Bin-Amphiphysin-Rvs (BAR) domain-containing proteins. This study investigates the roles of Drosophila ICA69 (dICA69) (an N-BAR protein) and Drosophila CIP4 (dCIP4) (an F-BAR protein), focusing on their impact on in vivo membrane tubule organization. In contrast to the prevailing models of BAR-domain protein function, we observed colocalization of endogenous dICA69 with dCIP4-induced tubules, indicating their potential recruitment for tubule formation and maintenance. Moreover, actin-regulatory proteins such as Wasp, SCAR, and Arp2/3 were recruited at the site of CIP4-induced tubule formation. An earlier study indicated that F-BAR proteins spontaneously segregate from the N-BAR domain proteins during membrane tubule formation. In contrast, our observation supports a model in which different BAR-domain family members can associate with the same tubule and cooperate to fine-tune the tubule width, possibly by recruiting actin modulators during the generation of tubules. Our data suggests that cooperative activities of distinct BAR-domain family proteins may determine the length and width of the membrane tubule in vivo.
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Affiliation(s)
| | | | | | - Sajad Bhat
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Indore bypass Road, Bhopal 462 066, Madhya Pradesh, India
| | - Surabhi Mukherjee
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Indore bypass Road, Bhopal 462 066, Madhya Pradesh, India
| | - Vimlesh Kumar
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Indore bypass Road, Bhopal 462 066, Madhya Pradesh, India
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2
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Kushwaha S, Mallik B, Bisht A, Mushtaq Z, Pippadpally S, Chandra N, Das S, Ratnaparkhi G, Kumar V. dAsap regulates cellular protrusions via an Arf6-dependent actin regulatory pathway in S2R+ cells. FEBS Lett 2024; 598:1491-1505. [PMID: 38862211 DOI: 10.1002/1873-3468.14954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/05/2024] [Accepted: 05/10/2024] [Indexed: 06/13/2024]
Abstract
Membrane protrusions are fundamental to cellular functions like migration, adhesion, and communication and depend upon dynamic reorganization of the cytoskeleton. GAP-dependent GTP hydrolysis of Arf proteins regulates actin-dependent membrane remodeling. Here, we show that dAsap regulates membrane protrusions in S2R+ cells by a mechanism that critically relies on its ArfGAP domain and relocalization of actin regulators, SCAR, and Ena. While our data reinforce the preference of dAsap for Arf1 GTP hydrolysis in vitro, we demonstrate that induction of membrane protrusions in S2R+ cells depends on Arf6 inactivation. This study furthers our understanding of how dAsap-dependent GTP hydrolysis maintains a balance between active and inactive states of Arf6 to regulate cell shape.
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Affiliation(s)
- Shikha Kushwaha
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
| | - Bhagaban Mallik
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
| | - Anjali Bisht
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
| | - Zeeshan Mushtaq
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
| | - Srikanth Pippadpally
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
| | - Nitika Chandra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
| | - Subhradip Das
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Pune, India
| | - Girish Ratnaparkhi
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Pune, India
| | - Vimlesh Kumar
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India
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3
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Fukaya M, Ibuchi K, Sugawara T, Itakura M, Ito A, Shiroshima T, Hara Y, Okamoto H, Luton F, Sakagami H. EFA6A, an Exchange Factor for Arf6, Regulates NGF-Dependent TrkA Recycling From Early Endosomes and Neurite Outgrowth in PC12 Cells. Traffic 2024; 25:e12936. [PMID: 38725127 DOI: 10.1111/tra.12936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 12/18/2023] [Accepted: 12/26/2023] [Indexed: 06/03/2024]
Abstract
Endosomal trafficking of TrkA is a critical process for nerve growth factor (NGF)-dependent neuronal cell survival and differentiation. The small GTPase ADP-ribosylation factor 6 (Arf6) is implicated in NGF-dependent processes in PC12 cells through endosomal trafficking and actin cytoskeleton reorganization. However, the regulatory mechanism for Arf6 in NGF signaling is largely unknown. In this study, we demonstrated that EFA6A, an Arf6-specific guanine nucleotide exchange factor, was abundantly expressed in PC12 cells and that knockdown of EFA6A significantly inhibited NGF-dependent Arf6 activation, TrkA recycling from early endosomes to the cell surface, prolonged ERK1/2 phosphorylation, and neurite outgrowth. We also demonstrated that EFA6A forms a protein complex with TrkA through its N-terminal region, thereby enhancing its catalytic activity for Arf6. Similarly, we demonstrated that EFA6A forms a protein complex with TrkA in cultured dorsal root ganglion (DRG) neurons. Furthermore, cultured DRG neurons from EFA6A knockout mice exhibited disturbed NGF-dependent TrkA trafficking compared with wild-type neurons. These findings provide the first evidence for EFA6A as a key regulator of NGF-dependent TrkA trafficking and signaling.
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Affiliation(s)
- Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - Kanta Ibuchi
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - Takeyuki Sugawara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Japan
| | - Akiko Ito
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Japan
| | - Tomoko Shiroshima
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - Yoshinobu Hara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - Hirotsugu Okamoto
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Japan
| | - Frédéric Luton
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Université Côte d'Azur, Valbonne, France
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
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4
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Sandhu A, Lyu X, Wan X, Meng X, Tang NH, Gonzalez G, Syed IN, Chen L, Jin Y, Chisholm AD. The microtubule regulator EFA-6 forms spatially restricted cortical foci dependent on its intrinsically disordered region and interactions with tubulins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.14.588158. [PMID: 38645057 PMCID: PMC11030407 DOI: 10.1101/2024.04.14.588158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Microtubules (MTs) are dynamic components of the cytoskeleton and play essential roles in morphogenesis and maintenance of tissue and cell integrity. Despite recent advances in understanding MT ultrastructure, organization, and growth control, how cells regulate MT organization at the cell cortex remains poorly understood. The EFA-6/EFA6 proteins are recently identified membrane-associated proteins that inhibit cortical MT dynamics. Here, combining visualization of endogenously tagged C. elegans EFA-6 with genetic screening, we uncovered tubulin-dependent regulation of EFA-6 patterning. In the mature epidermal epithelium, EFA-6 forms punctate foci in specific regions of the apical cortex, dependent on its intrinsically disordered region (IDR). We further show the EFA-6 IDR is sufficient to form biomolecular condensates in vitro. In screens for mutants with altered GFP::EFA-6 localization, we identified a novel gain-of-function (gf) mutation in an α-tubulin tba-1 that induces ectopic EFA-6 foci in multiple cell types. tba-1(gf) animals exhibit temperature-sensitive embryonic lethality, which is partially suppressed by efa-6(lf), indicating the interaction between tubulins and EFA-6 is important for normal development. TBA-1(gf) shows reduced incorporation into filamentous MTs but has otherwise mild effects on cellular MT organization. The ability of TBA-1(gf) to trigger ectopic EFA-6 foci formation requires β-tubulin TBB-2 and the chaperon EVL-20/Arl2. The tba-1(gf)-induced EFA-6 foci display slower turnover, contain the MT-associated protein TAC-1/TACC, and require the EFA-6 MTED. Our results reveal a novel crosstalk between cellular tubulins and cortical MT regulators in vivo.
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Affiliation(s)
- Anjali Sandhu
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, CA 92093 USA
| | - Xiaohui Lyu
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, CA 92093 USA
| | - Xinghaoyun Wan
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, CA 92093 USA
| | - Xuefeng Meng
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, CA 92093 USA
| | - Ngang Heok Tang
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, CA 92093 USA
| | - Gilberto Gonzalez
- Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Ishana N. Syed
- Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Lizhen Chen
- Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Yishi Jin
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, CA 92093 USA
| | - Andrew D. Chisholm
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, CA 92093 USA
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, CA 92093 USA
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5
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Yang LQ, Huang AF, Xu WD. Biology of endophilin and it's role in disease. Front Immunol 2023; 14:1297506. [PMID: 38116012 PMCID: PMC10728279 DOI: 10.3389/fimmu.2023.1297506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Endophilin is an evolutionarily conserved family of protein that involves in a range of intracellular membrane dynamics. This family consists of five isoforms, which are distributed in various tissues. Recent studies have shown that Endophilin regulates diseases pathogenesis, including neurodegenerative diseases, tumors, cardiovascular diseases, and autoimmune diseases. In vivo, it regulates different biological functions such as vesicle endocytosis, mitochondrial morphological changes, apoptosis and autophagosome formation. Functional studies confirmed the role of Endophilin in development and progression of these diseases. In this study, we have comprehensively discussed the complex function of Endophilin and how the family contributes to diseases development. It is hoped that this study will provide new ideas for targeting Endophilin in diseases.
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Affiliation(s)
- Lu-Qi Yang
- Department of Evidence-Based Medicine, Southwest Medical University, Luzhou, Sichuan, China
| | - An-Fang Huang
- Department of Rheumatology and Immunology, Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan, China
| | - Wang-Dong Xu
- Department of Evidence-Based Medicine, Southwest Medical University, Luzhou, Sichuan, China
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6
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Song DY, Yuan L, Cui N, Feng C, Meng L, Wang XH, Xiang M, Liu D, Wang C, Zhang Z, Li JY, Li W. α-Synuclein induces deficiency in clathrin-mediated endocytosis through inhibiting synaptojanin1 expression. J Neurochem 2023; 167:461-484. [PMID: 37788328 DOI: 10.1111/jnc.15974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/13/2023] [Accepted: 09/13/2023] [Indexed: 10/05/2023]
Abstract
Parkinson's disease (PD) is an age-related chronic neurological disorder, mainly characterized by the pathological feature of α-synuclein (α-syn) aggregation, with the exact disease pathogenesis unclear. During the onset and progression of PD, synaptic dysfunction, including dysregulation of axonal transport, impaired exocytosis, and endocytosis are identified as crucial events of PD pathogenesis. It has been reported that over-expression of α-syn impairs clathrin-mediated endocytosis (CME) in the synapses. However, the underlying mechanisms still needs to be explored. In this study, we investigated the molecular events underlying the synaptic dysfunction caused by over-expression of wild-type human α-syn and its mutant form, involving series of proteins participating in CME. We found that excessive human α-syn causes impaired fission and uncoating of clathrin-coated vesicles during synaptic vesicle recycling, leading to reduced clustering of synaptic vesicles near the active zone and increased size of plasma membrane and number of endocytic intermediates. Furthermore, over-expressed human α-syn induced changes of CME-associated proteins, among which synaptojanin1 (SYNJ1) showed significant reduction in various brain regions. Over-expression of SYNJ1 in primary hippocampal neurons from α-syn transgenic mice recovered the synaptic vesicle density, clustering and endocytosis. Using fluorescence-conjugated transferrin, we demonstrated that SYNJ1 re-boosted the CME activity by restoring the phosphatidylinositol-4,5-bisphosphate homeostasis. Our data suggested that over-expression of α-syn disrupts synaptic function through interfering with vesicle recycling, which could be alleviated by re-availing of SYNJ1. Our study unrevealed a molecular mechanism of the synaptic dysfunction in PD pathogenesis and provided a potential therapeutic target for treating PD.
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Affiliation(s)
- Dong-Yan Song
- Institute of Neuroscience, College of Life and Health Sciences, Northeastern University, Shenyang, China
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Lin Yuan
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Na Cui
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Cong Feng
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xin-He Wang
- Institute of Neuroscience, College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Man Xiang
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Di Liu
- Institute of Neuroscience, College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Chun Wang
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jia-Yi Li
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
- Neural Plasticity and Repair Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | - Wen Li
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
- Neural Plasticity and Repair Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
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7
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Sun D, Guo Y, Tang P, Li H, Chen L. Arf6 as a therapeutic target: Structure, mechanism, and inhibitors. Acta Pharm Sin B 2023; 13:4089-4104. [PMID: 37799386 PMCID: PMC10547916 DOI: 10.1016/j.apsb.2023.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/28/2023] [Accepted: 06/02/2023] [Indexed: 10/07/2023] Open
Abstract
ADP-ribosylation factor 6 (Arf6), a small G-protein of the Ras superfamily, plays pivotal roles in multiple cellular events, including exocytosis, endocytosis, actin remodeling, plasma membrane reorganization and vesicular transport. Arf6 regulates the progression of cancer through the activation of cell motility and invasion. Aberrant Arf6 activation is a potential therapeutic target. This review aims to understand the comprehensive function of Arf6 for future cancer therapy. The Arf6 GEFs, protein structure, and roles in cancer have been summarized. Comprehending the mechanism underlying Arf6-mediated cancer cell growth and survival is essential. The structural features of Arf6 and its efforts are discussed and may be contributed to the discovery of future novel protein-protein interaction inhibitors. In addition, Arf6 inhibitors and mechanism of action are listed in the table. This review further emphasizes the crucial roles in drug resistance and attempts to offer an outlook of Arf6 in cancer therapy.
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Affiliation(s)
- Dejuan Sun
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Yuanyuan Guo
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Piyu Tang
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Hua Li
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
| | - Lixia Chen
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
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8
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Hammood M, Craig AW, Leyton JV. Impact of Endocytosis Mechanisms for the Receptors Targeted by the Currently Approved Antibody-Drug Conjugates (ADCs)-A Necessity for Future ADC Research and Development. Pharmaceuticals (Basel) 2021; 14:ph14070674. [PMID: 34358100 PMCID: PMC8308841 DOI: 10.3390/ph14070674] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/10/2021] [Accepted: 07/13/2021] [Indexed: 12/17/2022] Open
Abstract
Biologically-based therapies increasingly rely on the endocytic cycle of internalization and exocytosis of target receptors for cancer therapies. However, receptor trafficking pathways (endosomal sorting (recycling, lysosome localization) and lateral membrane movement) are often dysfunctional in cancer. Antibody-drug conjugates (ADCs) have revitalized the concept of targeted chemotherapy by coupling inhibitory antibodies to cytotoxic payloads. Significant advances in ADC technology and format, and target biology have hastened the FDA approval of nine ADCs (four since 2019). Although the links between aberrant endocytic machinery and cancer are emerging, the impact of dysregulated internalization processes of ADC targets and response rates or resistance have not been well studied. This is despite the reliance on ADC uptake and trafficking to lysosomes for linker cleavage and payload release. In this review, we describe what is known about all the target antigens for the currently approved ADCs. Specifically, internalization efficiency and relevant intracellular sorting activities are described for each receptor under normal processes, and when complexed to an ADC. In addition, we discuss aberrant endocytic processes that have been directly linked to preclinical ADC resistance mechanisms. The implications of endocytosis in regard to therapeutic effectiveness in the clinic are also described. Unexpectedly, information on endocytosis is scarce (absent for two receptors). Moreover, much of what is known about endocytosis is not in the context of receptor-ADC/antibody complexes. This review provides a deeper understanding of the pertinent principles of receptor endocytosis for the currently approved ADCs.
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Affiliation(s)
- Manar Hammood
- Departément de Medécine Nucléaire et Radiobiologie, Faculté de Medécine et des Sciences de la Santé, Centre Hospitalier Universitaire de Sherbrooke (CHUS), Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada;
| | - Andrew W. Craig
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON K7L 3N6, Canada;
| | - Jeffrey V. Leyton
- Departément de Medécine Nucléaire et Radiobiologie, Faculté de Medécine et des Sciences de la Santé, Centre Hospitalier Universitaire de Sherbrooke (CHUS), Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada;
- Centre d’Imagerie Moleculaire, Centre de Recherche, CHUS, Sherbrooke, QC J1H 5N4, Canada
- Correspondence: ; Tel.: +1-819-346-1110
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9
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Mishra R, Sengül GF, Candiello E, Schu P. Synaptic AP2 CCV life cycle regulation by the Eps15, ITSN1, Sgip1/AP2, synaptojanin1 interactome. Sci Rep 2021; 11:8007. [PMID: 33850201 PMCID: PMC8044098 DOI: 10.1038/s41598-021-87591-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/30/2021] [Indexed: 11/18/2022] Open
Abstract
The AP1/σ1B knockout causes impaired synaptic vesicle recycling and enhanced protein sorting into endosomes, leading to severe intellectual disability. These disturbances in synaptic protein sorting induce as a secondary phenotype the upregulation of AP2 CCV mediated endocytosis. Synapses contain canonical AP2 CCV and AP2 CCV with a more stable coat and thus extended life time. In AP1/σ1B knockout synapses, pool sizes of both CCV classes are doubled. Additionally, stable CCV of the knockout are more stabilised than stable wt CCV. One mechanism responsible for enhanced CCV stabilisation is the reduction of synaptojanin1 CCV levels, the PI-4,5-P2 phosphatase essential for AP2 membrane dissociation. To identify mechanisms regulating synaptojanin1 recruitment, we compared synaptojanin1 CCV protein interactome levels and CCV protein interactions between both CCV classes from wt and knockout mice. We show that ITSN1 determines synaptojanin1 CCV levels. Sgip1/AP2 excess hinders synaptojanin1 binding to ITSN1, further lowering its levels. ITSN1 levels are determined by Eps15, not Eps15L1. In addition, the data reveal that reduced amounts of pacsin1 can be counter balanced by its enhanced activation. These data exemplify the complexity of CCV life cycle regulation and indicate how cargo proteins determine the life cycle of their CCV.
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Affiliation(s)
- R Mishra
- Department of Cellular Biochemistry, University Medical Center, Georg-August University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Cambridge, England, UK
| | - G F Sengül
- Department of Cellular Biochemistry, University Medical Center, Georg-August University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - E Candiello
- Department of Cellular Biochemistry, University Medical Center, Georg-August University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
- Institute for Cancer Research and Treatment (IRCC), Turin, Italy
| | - P Schu
- Department of Cellular Biochemistry, University Medical Center, Georg-August University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.
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10
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Chlortetracycline, a Novel Arf Inhibitor That Decreases the Arf6-Dependent Invasive Properties of Breast Cancer Cells. Molecules 2021; 26:molecules26040969. [PMID: 33673086 PMCID: PMC7917842 DOI: 10.3390/molecules26040969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/11/2022] Open
Abstract
Breast cancer is a major disease for women worldwide, where mortality is associated with tumour cell dissemination to distant organs. While the number of efficient anticancer therapies increased in the past 20 years, treatments targeting the invasive properties of metastatic tumour cells are still awaited. Various studies analysing invasive breast cancer cell lines have demonstrated that Arf6 is an important player of the migratory and invasive processes. These observations make Arf6 and its regulators potential therapeutic targets. As of today, no drug effective against Arf6 has been identified, with one explanation being that the activation of Arf6 is dependent on the presence of lipid membranes that are rarely included in drug screening. To overcome this issue we have set up a fluorescence-based high throughput screening that follows overtime the activation of Arf6 at the surface of lipid membranes. Using this unique screening assay, we isolated several compounds that affect Arf6 activation, among which the antibiotic chlortetracycline (CTC) appeared to be the most promising. In this report, we describe CTC in vitro biochemical characterization and show that it blocks both the Arf6-stimulated collective migration and cell invasion in a 3D collagen I gel of the invasive breast cancer cell line MDA-MB-231. Thus, CTC appears as a promising hit to target deadly metastatic dissemination and a powerful tool to unravel the molecular mechanisms of Arf6-mediated invasive processes.
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11
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Leite DM, Matias D, Battaglia G. The Role of BAR Proteins and the Glycocalyx in Brain Endothelium Transcytosis. Cells 2020; 9:E2685. [PMID: 33327645 PMCID: PMC7765129 DOI: 10.3390/cells9122685] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 12/27/2022] Open
Abstract
Within the brain, endothelial cells lining the blood vessels meticulously coordinate the transport of nutrients, energy metabolites and other macromolecules essential in maintaining an appropriate activity of the brain. While small molecules are pumped across specialised molecular transporters, large macromolecular cargos are shuttled from one side to the other through membrane-bound carriers formed by endocytosis on one side, trafficked to the other side and released by exocytosis. Such a process is collectively known as transcytosis. The brain endothelium is recognised to possess an intricate vesicular endosomal network that mediates the transcellular transport of cargos from blood-to-brain and brain-to-blood. However, mounting evidence suggests that brain endothelial cells (BECs) employ a more direct route via tubular carriers for a fast and efficient transport from the blood to the brain. Here, we compile the mechanism of transcytosis in BECs, in which we highlight intracellular trafficking mediated by tubulation, and emphasise the possible role in transcytosis of the Bin/Amphiphysin/Rvs (BAR) proteins and glycocalyx (GC)-a layer of sugars covering BECs, in transcytosis. Both BAR proteins and the GC are intrinsically associated with cell membranes and involved in the modulation and shaping of these membranes. Hence, we aim to summarise the machinery involved in transcytosis in BECs and highlight an uncovered role of BAR proteins and the GC at the brain endothelium.
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Affiliation(s)
- Diana M. Leite
- Department of Chemistry, University College London, London WC1H 0AJ, UK; (D.M.L.); (D.M.)
- Institute of the Physics and Living Systems, University College London, London WC1H 0AJ, UK
| | - Diana Matias
- Department of Chemistry, University College London, London WC1H 0AJ, UK; (D.M.L.); (D.M.)
- Institute of the Physics and Living Systems, University College London, London WC1H 0AJ, UK
- Samantha Dickson Brain Cancer Unit, Cancer Institute, University College London, London WC1E 06DD, UK
- Cancer Research UK, City of London Centre, London WC1E 06DD, UK
| | - Giuseppe Battaglia
- Department of Chemistry, University College London, London WC1H 0AJ, UK; (D.M.L.); (D.M.)
- Institute of the Physics and Living Systems, University College London, London WC1H 0AJ, UK
- Cancer Research UK, City of London Centre, London WC1E 06DD, UK
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), 08028 Barcelona, Spain
- Catalan Institute for Research and Advanced Studies, 08010 Barcelona, Spain
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12
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BRAG2a Mediates mGluR-Dependent AMPA Receptor Internalization at Excitatory Postsynapses through the Interaction with PSD-95 and Endophilin 3. J Neurosci 2020; 40:4277-4296. [PMID: 32341099 DOI: 10.1523/jneurosci.1645-19.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/06/2019] [Accepted: 04/17/2020] [Indexed: 11/21/2022] Open
Abstract
Brefeldin A-resistant ArfGEF 2 (BRAG2) [or Iqsec1 (IQ motif and Sec7 domain-containing protein 1)] is a guanine nucleotide exchange factor for ADP ribosylation factor 6 (Arf6), a small GTPase implicated in the membrane trafficking between the plasma membrane and endosomes. BRAG2 regulates Arf6-dependent endocytosis of AMPA receptors (AMPARs) through the direct interaction during the hippocampal long-term depression. However, the molecular mechanism by which the BRAG2-Arf6 pathway links AMPARs to the endocytic machinery remains elusive. Herein, using mouse brains of both sexes, we demonstrated that BRAG2a, an alternative isoform with a long C-terminal insert containing a proline-rich domain and type I PDZ-binding motif, was selectively localized to the excitatory postsynaptic density (PSD). Using yeast two-hybrid screening, we identified PSD-95 and endophilin 1/3 as BRAG2a-binding partners in the brain. The interaction with PSD-95 was required for synaptic targeting of BRAG2a. In cultured hippocampal neurons, stimulation of group I metabotropic glutamate receptors (mGluRs) increased the interaction of BRAG2a with endophilin 3 and concomitant Arf6 activation in a time-dependent manner. Knockdown of BRAG2 in cultured hippocampal neurons blocked the mGluR-dependent decrease in surface AMPAR levels, which was rescued by introducing wild-type BRAG2a, but not wild-type BRAG2b or BRAG2a mutants lacking the ability to activate Arf6 or to interact with endophilin 3 or PSD-95. Further postembedding immunoelectron microscopic analysis revealed the preorganized lateral distribution of BRAG2a, Arf6, and endophilin 3 for efficient endocytosis at the postsynaptic membrane. Together, the present findings unveiled a novel molecular mechanism by which BRAG2a links AMPARs to the clathrin-dependent endocytic pathway through its interaction with PSD-95 and endophilin 3.SIGNIFICANCE STATEMENT BRAG2/Iqsec1 is a GDP/GTP exchange factor for ADP ribosylation factor 6 (Arf6), a small GTPase implicated in the membrane trafficking between the plasma membrane and endosomes, and regulates Arf6-dependent endocytosis of AMPARs through direct interaction during hippocampal long-term depression, one of the mechanisms of synaptic plasticity related to learning and memory. However, the molecular mechanism by which the BRAG2-Arf6 pathway links AMPARs to the endocytic machinery remains elusive. Here, we identified isoform-specific mechanisms of BRAG2-mediated AMPAR internalization. We demonstrated that the interaction of BRAG2a isoform with PSD-95 and endophilin 3 was required for the mGluR-dependent decrease in surface AMPARs in hippocampal neurons. These results unveiled a novel molecular mechanism by which BRAG2 links AMPARs to the clathrin-mediated endocytic machinery at postsynaptic sites.
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13
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The C-terminal domain of EFA6A interacts directly with F-actin and assembles F-actin bundles. Sci Rep 2019; 9:19209. [PMID: 31844082 PMCID: PMC6915736 DOI: 10.1038/s41598-019-55630-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 11/28/2019] [Indexed: 01/08/2023] Open
Abstract
The Arf6-specific exchange factor EFA6 is involved in the endocytic/recycling pathway for different cargos. In addition EFA6 acts as a powerful actin cytoskeleton organizer, a function required for its role in the establishment of the epithelial cell polarity and in neuronal morphogenesis. We previously showed that the C-terminus of EFA6 (EFA6-Ct) is the main domain which contributes to actin reorganization. Here, by in vitro and in vivo experiments, we sought to decipher, at the molecular level, how EFA6 controls the dynamic and structuring of actin filaments. We showed that EFA6-Ct interferes with actin polymerization by interacting with and capping actin filament barbed ends. Further, in the presence of actin mono-filaments, the addition of EFA6-Ct triggered the formation of actin bundles. In cells, when the EFA6-Ct was directed to the plasma membrane, as is the case for the full-length protein, its expression induced the formation of membrane protrusions enriched in actin cables. Collectively our data explain, at least in part, how EFA6 plays an essential role in actin organization by interacting with and bundling F-actin.
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14
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Connor-Robson N, Booth H, Martin JG, Gao B, Li K, Doig N, Vowles J, Browne C, Klinger L, Juhasz P, Klein C, Cowley SA, Bolam P, Hirst W, Wade-Martins R. An integrated transcriptomics and proteomics analysis reveals functional endocytic dysregulation caused by mutations in LRRK2. Neurobiol Dis 2019; 127:512-526. [PMID: 30954703 PMCID: PMC6597903 DOI: 10.1016/j.nbd.2019.04.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/20/2019] [Accepted: 04/03/2019] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Mutations in LRRK2 are the most common cause of autosomal dominant Parkinson's disease, and the relevance of LRRK2 to the sporadic form of the disease is becoming ever more apparent. It is therefore essential that studies are conducted to improve our understanding of the cellular role of this protein. Here we use multiple models and techniques to identify the pathways through which LRRK2 mutations may lead to the development of Parkinson's disease. METHODS A novel integrated transcriptomics and proteomics approach was used to identify pathways that were significantly altered in iPSC-derived dopaminergic neurons carrying the LRRK2-G2019S mutation. Western blotting, immunostaining and functional assays including FM1-43 analysis of synaptic vesicle endocytosis were performed to confirm these findings in iPSC-derived dopaminergic neuronal cultures carrying either the LRRK2-G2019S or the LRRK2-R1441C mutation, and LRRK2 BAC transgenic rats, and post-mortem human brain tissue from LRRK2-G2019S patients. RESULTS Our integrated -omics analysis revealed highly significant dysregulation of the endocytic pathway in iPSC-derived dopaminergic neurons carrying the LRRK2-G2019S mutation. Western blot analysis confirmed that key endocytic proteins including endophilin I-III, dynamin-1, and various RAB proteins were downregulated in these cultures and in cultures carrying the LRRK2-R1441C mutation, compared with controls. We also found changes in expression of 25 RAB proteins. Changes in endocytic protein expression led to a functional impairment in clathrin-mediated synaptic vesicle endocytosis. Further to this, we found that the endocytic pathway was also perturbed in striatal tissue of aged LRRK2 BAC transgenic rats overexpressing either the LRRK2 wildtype, LRRK2-R1441C or LRRK2-G2019S transgenes. Finally, we found that clathrin heavy chain and endophilin I-III levels are increased in human post-mortem tissue from LRRK2-G2019S patients compared with controls. CONCLUSIONS Our study demonstrates extensive alterations across the endocytic pathway associated with LRRK2 mutations in iPSC-derived dopaminergic neurons and BAC transgenic rats, as well as in post-mortem brain tissue from PD patients carrying a LRRK2 mutation. In particular, we find evidence of disrupted clathrin-mediated endocytosis and suggest that LRRK2-mediated PD pathogenesis may arise through dysregulation of this process.
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Affiliation(s)
- Natalie Connor-Robson
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
| | - Heather Booth
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | | | | | - Natalie Doig
- Medical Research Council Brain Network Dynamics Unit, University of Oxford, Oxford, UK.
| | - Jane Vowles
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.; Oxford Parkinson's Disease Centre (OPDC), Oxford, UK.
| | - Cathy Browne
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK..
| | - Laura Klinger
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
| | | | - Christine Klein
- Institute of Neurogenetics, University of Leubeck, Maria-Goeppert-Str. 1, 23562 Luebeck, Germany..
| | - Sally A Cowley
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.; Oxford Parkinson's Disease Centre (OPDC), Oxford, UK.
| | - Paul Bolam
- Medical Research Council Brain Network Dynamics Unit, University of Oxford, Oxford, UK; Oxford Parkinson's Disease Centre (OPDC), Oxford, UK.
| | | | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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15
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Wang H, Liu Y, Zhang L, Kundu JK, Liu W, Wang X. ADP ribosylation factor 1 facilitates spread of wheat dwarf virus in its insect vector. Cell Microbiol 2019; 21:e13047. [DOI: 10.1111/cmi.13047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/01/2019] [Accepted: 05/13/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Hui Wang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing China
| | - Yan Liu
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing China
| | - Lu Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing China
| | - Jiban Kumar Kundu
- Division of Crop Protection and Plant HealthCrop Research Institute Praha 6 Czech Republic
| | - Wenwen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing China
| | - Xifeng Wang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing China
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16
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Sztul E, Chen PW, Casanova JE, Cherfils J, Dacks JB, Lambright DG, Lee FJS, Randazzo PA, Santy LC, Schürmann A, Wilhelmi I, Yohe ME, Kahn RA. ARF GTPases and their GEFs and GAPs: concepts and challenges. Mol Biol Cell 2019; 30:1249-1271. [PMID: 31084567 PMCID: PMC6724607 DOI: 10.1091/mbc.e18-12-0820] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/26/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022] Open
Abstract
Detailed structural, biochemical, cell biological, and genetic studies of any gene/protein are required to develop models of its actions in cells. Studying a protein family in the aggregate yields additional information, as one can include analyses of their coevolution, acquisition or loss of functionalities, structural pliability, and the emergence of shared or variations in molecular mechanisms. An even richer understanding of cell biology can be achieved through evaluating functionally linked protein families. In this review, we summarize current knowledge of three protein families: the ARF GTPases, the guanine nucleotide exchange factors (ARF GEFs) that activate them, and the GTPase-activating proteins (ARF GAPs) that have the ability to both propagate and terminate signaling. However, despite decades of scrutiny, our understanding of how these essential proteins function in cells remains fragmentary. We believe that the inherent complexity of ARF signaling and its regulation by GEFs and GAPs will require the concerted effort of many laboratories working together, ideally within a consortium to optimally pool information and resources. The collaborative study of these three functionally connected families (≥70 mammalian genes) will yield transformative insights into regulation of cell signaling.
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Affiliation(s)
- Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Pei-Wen Chen
- Department of Biology, Williams College, Williamstown, MA 01267
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée, CNRS and Ecole Normale Supérieure Paris-Saclay, 94235 Cachan, France
| | - Joel B. Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - David G. Lambright
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Amherst, MA 01605
| | - Fang-Jen S. Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | | | - Lorraine C. Santy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
| | - Annette Schürmann
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Ilka Wilhelmi
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Marielle E. Yohe
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-3050
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17
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Zhao P, Chen B, Li L, Wu H, Li Y, Shaneen B, Zhan X, Gu N. Missing-in-metastasis protein promotes internalization of magnetic nanoparticles via association with clathrin light chain and Rab7. Biochim Biophys Acta Gen Subj 2019; 1863:502-510. [PMID: 30528490 PMCID: PMC8218922 DOI: 10.1016/j.bbagen.2018.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/05/2018] [Accepted: 12/04/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Magnetic nanoparticles (MNPs) have been widely used in biomedical applications. Proper control of the duration of MNPs in circulation promises to improve further their applications, in particularly drug delivery. It is known that the uptake of tissue-associated MNPs is mainly carried out by macrophages. Yet, the molecular mechanism to control MNPs internalization in macrophages remains to be elusive. Missing-in-metastasis (MIM) is a scaffolding protein that is highly expressed in macrophages and regulates receptor-mediated endocytosis. We hypothesize that uptake of MNPs may also involve the function of MIM. METHODS We investigated the effect of MIM expression on the intracellular trafficking of MNPs by transmission electronic microscopy, flow cytometry, o-phenanthroline photometric analysis, Perl's staining, immunofluorescence microscopy and co-immunoprecipitation. To explore the molecular events in MIM-mediated MNPs uptake, we examined the effect of MNPs on the interaction of MIM with clathrin, Rab5 and Rab7. RESULTS Uptake of MNPs was significantly enhanced in cells overexpressing MIM. Upon exposure to MNPs, MIM was associated with clathrin light chain in endocytic vesicles and Rab7, a protein that regulates late endosomes. However, MNPs caused dissociation of MIM with Rab5, an early endosome-associated protein. CONCLUSIONS MIM regulates internalization of MNPs via promoting their trafficking from plasma membrane to late endosomes. GENERAL SIGNIFICANCE Our data unveiled a novel pathway which MNPs internalization and intracellular trafficking in macrophages. This new pathway may allow us to control the uptake of MNPs within cells by targeting MIM, thereby improving their medical applications.
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Affiliation(s)
- Peng Zhao
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, PR China
| | - Bo Chen
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Materials Science and Devices Institute, Suzhou University of Science and Technology, 1 Kerui Road, Suzhou, Jiangsu 215009, PR China
| | - Lushen Li
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hao Wu
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 210029, PR China
| | - Yan Li
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, PR China
| | - Baxter Shaneen
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Xi Zhan
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Ning Gu
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, PR China.
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18
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Poudel KR, Roh-Johnson M, Su A, Ho T, Mathsyaraja H, Anderson S, Grady WM, Moens CB, Conacci-Sorrell M, Eisenman RN, Bai J. Competition between TIAM1 and Membranes Balances Endophilin A3 Activity in Cancer Metastasis. Dev Cell 2018; 45:738-752.e6. [PMID: 29920278 DOI: 10.1016/j.devcel.2018.05.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 04/10/2018] [Accepted: 05/17/2018] [Indexed: 11/19/2022]
Abstract
Normal cells acquire aggressive behavior by modifying signaling pathways. For instance, alteration of endocytosis profoundly impacts both proliferation and migration during tumorigenesis. Here we investigate the mechanisms that enable the endocytic machinery to coordinate these processes. We show that a membrane curvature-sensing protein, endophilin A3, promotes growth and migration of colon cancer cells through two competing mechanisms: an endocytosis pathway that is required for proliferation and a GTPase regulatory pathway that controls cell motility. EndoA3 stimulates cell migration by binding the Rac GEF TIAM1 leading to activation of small GTPases. Competing interactions of EndoA3 with membrane versus TIAM1 modulate hyperproliferative and metastatic phenotypes. Disruption of EndoA3-membrane interactions stimulates TIAM1 and small GTPases in vitro, and further promotes pro-metastatic phenotypes in vivo. Together, these results uncover a coupling mechanism, by which EndoA3 promotes growth and migration of colon cancers, by linking membrane dynamics to GTPase regulation.
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Affiliation(s)
- Kumud R Poudel
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Minna Roh-Johnson
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Allen Su
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Thuong Ho
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Haritha Mathsyaraja
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Sarah Anderson
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - William M Grady
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Cecilia B Moens
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | | | - Robert N Eisenman
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA.
| | - Jihong Bai
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA.
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19
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Gadahi JA, Ehsan M, Wang S, Zhang Z, Yan R, Song X, Xu L, Li X. Recombinant protein of Haemonchus contortus small GTPase ADP-ribosylation factor 1 (HcARF1) modulate the cell mediated immune response in vitro. Oncotarget 2017; 8:112211-112221. [PMID: 29348819 PMCID: PMC5762504 DOI: 10.18632/oncotarget.22662] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 11/03/2017] [Indexed: 01/08/2023] Open
Abstract
ADP-ribosylation factors (ARFs) are members of the Ras-related small GTPase family involved in the vesicular trafficking regulation. Immunomodulatory effects of these proteinson host cell arenot being addressed yet. H. contortus small GTPase ADP-ribosylation 1 gene (HcARF1) was cloned and recombinant protein of HcARF1 (rHcARF1) was successfully expressed in Escherichia coli. Binding activity of rHcARF1 to goat PBMCs was confirmed by immunofluorescence assay (IFA) and its immunomudulatory effects on cytokine secretion, cell proliferation, cell migration and nitric oxide production (NO) were observed by co-incubation of rHcARF1. IFA results revealed that rHcARF1 could bind to the PBMCs. The interaction of rHcARF1 modulated the cytokine production, the production of IL-4, IL-10 and IL-17 was increased in a dose dependent manner, however, the IFN-γ production was significantly decreased. Cell migration and NO production were significantly increased by rHcARF1, whereas, rHcARF1 treatment significantly suppressed the proliferation of the PBMC in a dose dependent manner. Our findings showed that the rHcARF1 play important roles on the goat PBMCs.
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Affiliation(s)
- Javaid Ali Gadahi
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China.,Department of Veterinary Parasitology, Sindh Agriculture University, Tando Jam, Pakistan
| | - Muhammad Ehsan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Shuai Wang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Zhenchao Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Ruofeng Yan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Xiaokai Song
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Lixin Xu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Xiangrui Li
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
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20
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Baldassarre T, Truesdell P, Craig AW. Endophilin A2 promotes HER2 internalization and sensitivity to trastuzumab-based therapy in HER2-positive breast cancers. Breast Cancer Res 2017; 19:110. [PMID: 28974266 PMCID: PMC5627411 DOI: 10.1186/s13058-017-0900-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 08/30/2017] [Indexed: 12/13/2022] Open
Abstract
Background Human epidermal growth factor receptor-2 (HER2) is amplified and a clinical target in a subset of human breast cancers with high rates of metastasis. Targeted therapies involving the antibody trastuzumab and trastuzumab-emtansine (T-DM1) have greatly improved outcomes for HER2-positive (HER2+) breast cancer patients. However, resistance to these targeted therapies can develop and limit their efficacy. Here, we test the involvement of the endocytic adaptor protein endophilin A2 (Endo II) in HER2+ breast cancer models, and their responses to treatments with trastuzumab and T-DM1. Methods Endo II expression in human breast tumors and lymph node metastases were analyzed by immunohistochemistry. Stable silencing of Endo II was achieved in HER2+ cancer cell lines (SK-BR-3 and HCC1954) to test Endo II effects on HER2 levels, localization and signaling, cell motility and tumor metastasis. The effects of Endo II silencing on the responses of HER2+ cancer cells to trastuzumab or T-DM1 treatments were tested using real-time cell motility and cytotoxicity assays. Results High Endo II protein expression was detected in HER2-positive tumors, and was linked to worse overall survival in node-positive HER2+ breast cancers at the mRNA level. Stable silencing of Endo II in HER2+ cell lines led to elevated levels of HER2 on the cell surface, impaired epidermal growth factor-induced HER2 internalization, and reduced signaling to downstream effector kinases Akt and Erk. Endo II silencing also led to decreased migration and invasion of HER2+ cancer cells in vitro, and impaired lung seeding following tail vein injection in mice. In addition, Endo II silencing also impaired HER2 internalization in response to Trastuzumab, and led to reduced cytotoxicity response in HER2+ cancer cells treated with T-DM1. Conclusions Our study provides novel evidence of Endo II function in HER2+ cancer cell motility and trafficking of HER2 that relates to effective treatments with trastuzumab or T-DM1. Thus, differential expression of Endo II may relate to sensitivity or resistance to trastuzumab-based therapies for HER2+ cancers. Electronic supplementary material The online version of this article (doi:10.1186/s13058-017-0900-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tomas Baldassarre
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.,Cancer Biology & Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada
| | - Peter Truesdell
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.,Cancer Biology & Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada
| | - Andrew W Craig
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada. .,Cancer Biology & Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada.
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21
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Salzer U, Kostan J, Djinović-Carugo K. Deciphering the BAR code of membrane modulators. Cell Mol Life Sci 2017; 74:2413-2438. [PMID: 28243699 PMCID: PMC5487894 DOI: 10.1007/s00018-017-2478-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 01/06/2023]
Abstract
The BAR domain is the eponymous domain of the “BAR-domain protein superfamily”, a large and diverse set of mostly multi-domain proteins that play eminent roles at the membrane cytoskeleton interface. BAR domain homodimers are the functional units that peripherally associate with lipid membranes and are involved in membrane sculpting activities. Differences in their intrinsic curvatures and lipid-binding properties account for a large variety in membrane modulating properties. Membrane activities of BAR domains are further modified and regulated by intramolecular or inter-subunit domains, by intermolecular protein interactions, and by posttranslational modifications. Rather than providing detailed cell biological information on single members of this superfamily, this review focuses on biochemical, biophysical, and structural aspects and on recent findings that paradigmatically promote our understanding of processes driven and modulated by BAR domains.
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Affiliation(s)
- Ulrich Salzer
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Julius Kostan
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Kristina Djinović-Carugo
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 119, 1000, Ljubljana, Slovenia.
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Lima S, Milstien S, Spiegel S. Sphingosine and Sphingosine Kinase 1 Involvement in Endocytic Membrane Trafficking. J Biol Chem 2017; 292:3074-3088. [PMID: 28049734 DOI: 10.1074/jbc.m116.762377] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/22/2016] [Indexed: 12/22/2022] Open
Abstract
The balance between cholesterol and sphingolipids within the plasma membrane has long been implicated in endocytic membrane trafficking. However, in contrast to cholesterol functions, little is still known about the roles of sphingolipids and their metabolites. Perturbing the cholesterol/sphingomyelin balance was shown to induce narrow tubular plasma membrane invaginations enriched with sphingosine kinase 1 (SphK1), the enzyme that converts the bioactive sphingolipid metabolite sphingosine to sphingosine-1-phosphate, and suggested a role for sphingosine phosphorylation in endocytic membrane trafficking. Here we show that sphingosine and sphingosine-like SphK1 inhibitors induced rapid and massive formation of vesicles in diverse cell types that accumulated as dilated late endosomes. However, much smaller vesicles were formed in SphK1-deficient cells. Moreover, inhibition or deletion of SphK1 prolonged the lifetime of sphingosine-induced vesicles. Perturbing the plasma membrane cholesterol/sphingomyelin balance abrogated vesicle formation. This massive endosomal influx was accompanied by dramatic recruitment of the intracellular SphK1 and Bin/Amphiphysin/Rvs domain-containing proteins endophilin-A2 and endophilin-B1 to enlarged endosomes and formation of highly dynamic filamentous networks containing endophilin-B1 and SphK1. Together, our results highlight the importance of sphingosine and its conversion to sphingosine-1-phosphate by SphK1 in endocytic membrane trafficking.
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Affiliation(s)
- Santiago Lima
- Department of Biochemistry and Molecular Biology and Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298.
| | - Sheldon Milstien
- Department of Biochemistry and Molecular Biology and Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology and Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298.
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ACAP3 regulates neurite outgrowth through its GAP activity specific to Arf6 in mouse hippocampal neurons. Biochem J 2016; 473:2591-602. [PMID: 27330119 DOI: 10.1042/bcj20160183] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/21/2016] [Indexed: 01/30/2023]
Abstract
ACAP3 (ArfGAP with coiled-coil, ankyrin repeat and pleckstrin homology domains 3) belongs to the ACAP family of GAPs (GTPase-activating proteins) for the small GTPase Arf (ADP-ribosylation factor). However, its specificity to Arf isoforms and physiological functions remain unclear. In the present study, we demonstrate that ACAP3 plays an important role in neurite outgrowth of mouse hippocampal neurons through its GAP activity specific to Arf6. In primary cultured mouse hippocampal neurons, knockdown of ACAP3 abrogated neurite outgrowth, which was rescued by ectopically expressed wild-type ACAP3, but not by its GAP activity-deficient mutant. Ectopically expressed ACAP3 in HEK (human embryonic kidney)-293T cells showed the GAP activity specific to Arf6. In support of this observation, the level of GTP-bound Arf6 was significantly increased by knockdown of ACAP3 in hippocampal neurons. In addition, knockdown and knockout of Arf6 in mouse hippocampal neurons suppressed neurite outgrowth. These results demonstrate that ACAP3 positively regulates neurite outgrowth through its GAP activity specific to Arf6. Furthermore, neurite outgrowth suppressed by ACAP3 knockdown was rescued by expression of a fast cycle mutant of Arf6 that spontaneously exchanges guanine nucleotides on Arf6, but not by that of wild-type, GTP- or GDP-locked mutant Arf6. Thus cycling between active and inactive forms of Arf6, which is precisely regulated by ACAP3 in concert with a guanine-nucleotide-exchange factor(s), seems to be required for neurite outgrowth of hippocampal neurons.
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Roy NS, Yohe ME, Randazzo PA, Gruschus JM. Allosteric properties of PH domains in Arf regulatory proteins. CELLULAR LOGISTICS 2016; 6:e1181700. [PMID: 27294009 DOI: 10.1080/21592799.2016.1181700] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/13/2016] [Accepted: 04/14/2016] [Indexed: 10/21/2022]
Abstract
Pleckstrin Homology (PH) domains bind phospholipids and proteins. They are critical regulatory elements of a number enzymes including guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) for Ras-superfamily guanine nucleotide binding proteins such as ADP-ribosylation factors (Arfs). Recent studies have indicated that many PH domains may bind more than one ligand cooperatively. Here we discuss the molecular basis of PH domain-dependent allosteric behavior of 2 ADP-ribosylation factor exchange factors, Grp1 and Brag2, cooperative binding of ligands to the PH domains of Grp1 and the Arf GTPase-activating protein, ASAP1, and the consequences for activity of the associated catalytic domains.
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Affiliation(s)
- Neeladri Sekhar Roy
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Marielle E Yohe
- Genetics Branch, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - James M Gruschus
- Laboratory of Structural Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health , Bethesda, MD, USA
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25
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Regulators and Effectors of Arf GTPases in Neutrophils. J Immunol Res 2015; 2015:235170. [PMID: 26609537 PMCID: PMC4644846 DOI: 10.1155/2015/235170] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/30/2015] [Indexed: 12/22/2022] Open
Abstract
Polymorphonuclear neutrophils (PMNs) are key innate immune cells that represent the first line of defence against infection. They are the first leukocytes to migrate from the blood to injured or infected sites. This process involves molecular mechanisms that coordinate cell polarization, delivery of receptors, and activation of integrins at the leading edge of migrating PMNs. These phagocytes actively engulf microorganisms or form neutrophil extracellular traps (NETs) to trap and kill pathogens with bactericidal compounds. Association of the NADPH oxidase complex at the phagosomal membrane for production of reactive oxygen species (ROS) and delivery of proteolytic enzymes into the phagosome initiate pathogen killing and removal. G protein-dependent signalling pathways tightly control PMN functions. In this review, we will focus on the small monomeric GTPases of the Arf family and their guanine exchange factors (GEFs) and GTPase activating proteins (GAPs) as components of signalling cascades regulating PMN responses. GEFs and GAPs are multidomain proteins that control cellular events in time and space through interaction with other proteins and lipids inside the cells. The number of Arf GAPs identified in PMNs is expanding, and dissecting their functions will provide important insights into the role of these proteins in PMN physiology.
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26
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Baldassarre T, Watt K, Truesdell P, Meens J, Schneider MM, Sengupta SK, Craig AW. Endophilin A2 Promotes TNBC Cell Invasion and Tumor Metastasis. Mol Cancer Res 2015; 13:1044-55. [PMID: 25784716 DOI: 10.1158/1541-7786.mcr-14-0573] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/08/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED Triple-negative breast cancers (TNBCs) are highly aggressive cancers that lack targeted therapies. However, EGFR is frequently activated in a subset of TNBCs and represents a viable clinical target. Because the endocytic adaptor protein Endophilin A2 (SH3GL1/Endo II) has been implicated in EGFR internalization, we investigated Endo II expression and function in human TNBCs. Endo II expression was high in several TNBC cells compared with normal breast epithelial cells. Stable knockdown (KD) of Endo II was achieved in two TNBC cell lines, and although cell viability was unaffected, defects in receptor-mediated endocytosis were observed. EGFR signaling to Erk and Akt kinases was impaired in Endo II KD cells, and this correlated with reduced rates of EGFR internalization and cell motility. Endo II KD cells also displayed defects in three dimensional (3D) cell invasion, and this correlated with impaired extracellular matrix degradation and internalization of MT1-MMP. Endo II silencing also caused a significant reduction in TNBC tumor growth and lung metastasis in mammary orthotopic tumor xenograft assays. In human breast tumor specimens, Endo II expression was highest in TNBC tumors compared with other subtypes, and at the level of gene expression, high Endo II was associated with reduced relapse-free survival in patients with basal-like breast cancers. Together, these results identify a positive role for Endo II in TNBC tumor metastasis and a potential link with poor prognosis. IMPLICATIONS Endophilin A2 and related adaptor proteins represent important signaling hubs to target in metastatic cancers.
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Affiliation(s)
- Tomas Baldassarre
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada. Cancer Biology and Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada
| | - Kathleen Watt
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada. Cancer Biology and Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada
| | - Peter Truesdell
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada. Cancer Biology and Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada
| | - Jalna Meens
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada. Cancer Biology and Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada
| | - Mark M Schneider
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, Canada
| | - Sandip K Sengupta
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, Canada
| | - Andrew W Craig
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada. Cancer Biology and Genetics Division, Queen's Cancer Research Institute, Kingston, Ontario, Canada.
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