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Budhiraja S, McManus G, Baisiwala S, Perrault EN, Cho S, Saathoff M, Chen L, Park CH, Kazi HA, Dmello C, Lin P, James CD, Sonabend AM, Heiland DH, Ahmed AU. ARF4-mediated retrograde trafficking as a driver of chemoresistance in glioblastoma. Neuro Oncol 2024; 26:1421-1437. [PMID: 38506351 PMCID: PMC11300013 DOI: 10.1093/neuonc/noae059] [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: 10/17/2023] [Indexed: 03/21/2024] Open
Abstract
BACKGROUND Cellular functions hinge on the meticulous orchestration of protein transport, both spatially and temporally. Central to this process is retrograde trafficking, responsible for targeting proteins to the nucleus. Despite its link to many diseases, the implications of retrograde trafficking in glioblastoma (GBM) are still unclear. METHODS To identify genetic drivers of TMZ resistance, we conducted comprehensive CRISPR-knockout screening, revealing ADP-ribosylation factor 4 (ARF4), a regulator of retrograde trafficking, as a major contributor. RESULTS Suppressing ARF4 significantly enhanced TMZ sensitivity in GBM patient-derived xenograft (PDX) models, leading to improved survival rates (P < .01) in both primary and recurrent lines. We also observed that TMZ exposure stimulates ARF4-mediated retrograde trafficking. Proteomics analysis of GBM cells with varying levels of ARF4 unveiled the influence of this pathway on EGFR signaling, with increased nuclear trafficking of EGFR observed in cells with ARF4 overexpression and TMZ treatment. Additionally, spatially resolved RNA-sequencing of GBM patient tissues revealed substantial correlations between ARF4 and crucial nuclear EGFR (nEGFR) downstream targets, such as MYC, STAT1, and DNA-PK. Decreased activity of DNA-PK, a DNA repair protein downstream of nEGFR signaling that contributes to TMZ resistance, was observed in cells with suppressed ARF4 levels. Notably, treatment with DNA-PK inhibitor, KU-57788, in mice with a recurrent PDX line resulted in prolonged survival (P < .01), highlighting the promising therapeutic implications of targeting proteins reliant on ARF4-mediated retrograde trafficking. CONCLUSIONS Our findings demonstrate that ARF4-mediated retrograde trafficking contributes to the development of TMZ resistance, cementing this pathway as a viable strategy to overcome chemoresistance in GBM.
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Affiliation(s)
- Shreya Budhiraja
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Northwestern Medicine Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Graysen McManus
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | | | - Ella N Perrault
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Sia Cho
- Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
| | - Miranda Saathoff
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Li Chen
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Cheol H Park
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Hasaan A Kazi
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Crismita Dmello
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Peiyu Lin
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - C David James
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Northwestern Medicine Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Adam M Sonabend
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Northwestern Medicine Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Dieter H Heiland
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Microenvironment and Immunology Research Laboratory, Medical Center - University of Freiburg, Freiburg, Germany
- Department of Neurosurgery, Medical Center - University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- German Cancer Consortium (DKTK), Freiburg, Germany
| | - Atique U Ahmed
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Northwestern Medicine Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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Gallop MR, Vieira RFL, Matsuzaki ET, Mower PD, Liou W, Smart FE, Roberts S, Evason KJ, Holland WL, Chaix A. Long-term ketogenic diet causes hyperlipidemia, liver dysfunction, and glucose intolerance from impaired insulin trafficking and secretion in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.599117. [PMID: 38948738 PMCID: PMC11212871 DOI: 10.1101/2024.06.14.599117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
A ketogenic diet (KD) is a very low-carbohydrate, very high-fat diet proposed to treat obesity and type 2 diabetes. While KD grows in popularity, its effects on metabolic health are understudied. Here we show that, in male and female mice, while KD protects against weight gain and induces weight loss, over long-term, mice develop hyperlipidemia, hepatic steatosis, and severe glucose intolerance. Unlike high fat diet-fed mice, KD mice are not insulin resistant and have low levels of insulin. Hyperglycemic clamp and ex vivo GSIS revealed cell-autonomous and whole-body impairments in insulin secretion. Major ER/Golgi stress and disrupted ER-Golgi protein trafficking was indicated by transcriptomic profiling of KD islets and confirmed by electron micrographs showing a dilated Golgi network likely responsible for impaired insulin granule trafficking and secretion. Overall, our results suggest long-term KD leads to multiple aberrations of metabolic parameters that caution its systematic use as a health promoting dietary intervention.
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Smith DM, Liu BY, Wolfgang MJ. Rab30 facilitates lipid homeostasis during fasting. Nat Commun 2024; 15:4469. [PMID: 38796472 PMCID: PMC11127972 DOI: 10.1038/s41467-024-48959-x] [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: 08/15/2023] [Accepted: 05/17/2024] [Indexed: 05/28/2024] Open
Abstract
To facilitate inter-tissue communication and the exchange of proteins, lipoproteins, and metabolites with the circulation, hepatocytes have an intricate and efficient intracellular trafficking system regulated by small Rab GTPases. Here, we show that Rab30 is induced in the mouse liver by fasting, which is amplified in liver-specific carnitine palmitoyltransferase 2 knockout mice (Cpt2L-/-) lacking the ability to oxidize fatty acids, in a Pparα-dependent manner. Live-cell super-resolution imaging and in vivo proximity labeling demonstrates that Rab30-marked vesicles are highly dynamic and interact with proteins throughout the secretory pathway. Rab30 whole-body, liver-specific, and Rab30; Cpt2 liver-specific double knockout (DKO) mice are viable with intact Golgi ultrastructure, although Rab30 deficiency in DKO mice suppresses the serum dyslipidemia observed in Cpt2L-/- mice. Corresponding with decreased serum triglyceride and cholesterol levels, DKO mice exhibit decreased circulating but not hepatic ApoA4 protein, indicative of a trafficking defect. Together, these data suggest a role for Rab30 in the selective sorting of lipoproteins to influence hepatocyte and circulating triglyceride levels, particularly during times of excessive lipid burden.
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Affiliation(s)
- Danielle M Smith
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Brian Y Liu
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Michael J Wolfgang
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Erol ÖD, Şenocak Ş, Aerts-Kaya F. The Role of Rab GTPases in the development of genetic and malignant diseases. Mol Cell Biochem 2024; 479:255-281. [PMID: 37060515 DOI: 10.1007/s11010-023-04727-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/01/2023] [Indexed: 04/16/2023]
Abstract
Small GTPases have been shown to play an important role in several cellular functions, including cytoskeletal remodeling, cell polarity, intracellular trafficking, cell-cycle, progression and lipid transformation. The Ras-associated binding (Rab) family of GTPases constitutes the largest family of GTPases and consists of almost 70 known members of small GTPases in humans, which are known to play an important role in the regulation of intracellular membrane trafficking, membrane identity, vesicle budding, uncoating, motility and fusion of membranes. Mutations in Rab genes can cause a wide range of inherited genetic diseases, ranging from neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD) to immune dysregulation/deficiency syndromes, like Griscelli Syndrome Type II (GS-II) and hemophagocytic lymphohistiocytosis (HLH), as well as a variety of cancers. Here, we provide an extended overview of human Rabs, discussing their function and diseases related to Rabs and Rab effectors, as well as focusing on effects of (aberrant) Rab expression. We aim to underline their importance in health and the development of genetic and malignant diseases by assessing their role in cellular structure, regulation, function and biology and discuss the possible use of stem cell gene therapy, as well as targeting of Rabs in order to treat malignancies, but also to monitor recurrence of cancer and metastasis through the use of Rabs as biomarkers. Future research should shed further light on the roles of Rabs in the development of multifactorial diseases, such as diabetes and assess Rabs as a possible treatment target.
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Affiliation(s)
- Özgür Doğuş Erol
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Şimal Şenocak
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Fatima Aerts-Kaya
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey.
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey.
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Kompotis K, Mang GM, Hubbard J, Jimenez S, Emmenegger Y, Polysopoulos C, Hor CN, Wigger L, Hébert SS, Mongrain V, Franken P. Cortical miR-709 links glutamatergic signaling to NREM sleep EEG slow waves in an activity-dependent manner. Proc Natl Acad Sci U S A 2024; 121:e2220532121. [PMID: 38207077 PMCID: PMC10801902 DOI: 10.1073/pnas.2220532121] [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: 12/09/2022] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression that have been implicated in a plethora of neuronal processes. Nevertheless, their role in regulating brain activity in the context of sleep has so far received little attention. To test their involvement, we deleted mature miRNAs in post-mitotic neurons at two developmental ages, i.e., in early adulthood using conditional Dicer knockout (cKO) mice and in adult mice using an inducible conditional Dicer cKO (icKO) line. In both models, electroencephalographic (EEG) activity was affected and the response to sleep deprivation (SD) altered; while the rapid-eye-movement sleep (REMS) rebound was compromised in both, the increase in EEG delta (1 to 4 Hz) power during non-REMS (NREMS) was smaller in cKO mice and larger in icKO mice compared to controls. We subsequently investigated the effects of SD on the forebrain miRNA transcriptome and found that the expression of 48 miRNAs was affected, and in particular that of the activity-dependent miR-709. In vivo inhibition of miR-709 in the brain increased EEG power during NREMS in the slow-delta (0.75 to 1.75 Hz) range, particularly after periods of prolonged wakefulness. Transcriptome analysis of primary cortical neurons in vitro revealed that miR-709 regulates genes involved in glutamatergic neurotransmission. A subset of these genes was also affected in the cortices of sleep-deprived, miR-709-inhibited mice. Our data implicate miRNAs in the regulation of EEG activity and indicate that miR-709 links neuronal activity during wakefulness to brain synchrony during sleep through the regulation of glutamatergic signaling.
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Affiliation(s)
- Konstantinos Kompotis
- Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, ZurichCH-8057, Switzerland
| | - Géraldine M. Mang
- Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
| | - Jeffrey Hubbard
- Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
| | - Sonia Jimenez
- Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
| | - Yann Emmenegger
- Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
| | - Christos Polysopoulos
- Department of Biostatistics, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, ZurichCH-8057, Switzerland
| | - Charlotte N. Hor
- Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
| | - Leonore Wigger
- Genomic Technologies Facility, Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
| | - Sébastien S. Hébert
- Centre de recherche du Centre hospitalier universitaire de Québec-Université Laval, Axe Neurosciences, Québec, QCG1V 4G2, Canada
- Département de psychiatrie et de neurosciences, Faculté de médecine, Université Laval, Québec, QCG1V 0A6, Canada
| | - Valérie Mongrain
- Department of Neuroscience, Université de Montréal, Montréal, QCH3T 1J4, Canada
- Centre de recherche, Centre hospitalier de l’Université de Montréal, Montréal, QCH2X 0A9, Canada
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, Montréal, QCH4J 1C5, Canada
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, LausanneCH-1015, Switzerland
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Vti1a/b support distinct aspects of TGN and cis-/medial Golgi organization. Sci Rep 2022; 12:20870. [PMID: 36460703 PMCID: PMC9718741 DOI: 10.1038/s41598-022-25331-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
Retrograde trafficking towards the trans-Golgi network (TGN) is important for dense core vesicle (DCV) biogenesis. Here, we used Vti1a/b deficient neurons to study the impact of disturbed retrograde trafficking on Golgi organization and cargo sorting. In Vti1a/b deficient neurons, staining intensity of cis-/medial Golgi proteins (e.g., GM130 and giantin) was increased, while the intensity of two recycling TGN proteins, TGN38 and TMEM87A, was decreased and the TGN-resident protein Golgin97 was normal. Levels and localization of DCV cargo markers, LAMP1 and KDEL were also altered. This phenotype was not caused by reduced Golgi size or absence of a TGN compartment. The phenotype was partially phenocopied by disturbing sphingolipid homeostasis, but was not rescued by overexpression of sphingomyelin synthases or the sphingolipid synthesis inhibitor myriocin. We conclude that Vti1a/b are important for distinct aspects of TGN and cis-/medial Golgi organization. Our data underline the importance of retrograde trafficking for Golgi organization, DCV cargo sorting and the distribution of proteins of the regulated secretory pathway.
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7
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Gundu C, Arruri VK, Yadav P, Navik U, Kumar A, Amalkar VS, Vikram A, Gaddam RR. Dynamin-Independent Mechanisms of Endocytosis and Receptor Trafficking. Cells 2022; 11:cells11162557. [PMID: 36010634 PMCID: PMC9406725 DOI: 10.3390/cells11162557] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/03/2022] [Accepted: 08/13/2022] [Indexed: 11/16/2022] Open
Abstract
Endocytosis is a fundamental mechanism by which cells perform housekeeping functions. It occurs via a variety of mechanisms and involves many regulatory proteins. The GTPase dynamin acts as a “molecular scissor” to form endocytic vesicles and is a critical regulator among the proteins involved in endocytosis. Some GTPases (e.g., Cdc42, arf6, RhoA), membrane proteins (e.g., flotillins, tetraspanins), and secondary messengers (e.g., calcium) mediate dynamin-independent endocytosis. These pathways may be convergent, as multiple pathways exist in a single cell. However, what determines the specific path of endocytosis is complex and challenging to comprehend. This review summarizes the mechanisms of dynamin-independent endocytosis, the involvement of microRNAs, and factors that contribute to the cellular decision about the specific route of endocytosis.
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Affiliation(s)
- Chayanika Gundu
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad 500037, Telangana, India
| | - Vijay Kumar Arruri
- Department of Neurological Surgery, University of Wisconsin, Madison, WI 53792, USA
| | - Poonam Yadav
- Department of Pharmacology, Central University of Punjab, Bathinda 151001, Punjab, India
| | - Umashanker Navik
- Department of Pharmacology, Central University of Punjab, Bathinda 151001, Punjab, India
| | - Ashutosh Kumar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Kolkata 700054, West Bengal, India
| | - Veda Sudhir Amalkar
- Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Ajit Vikram
- Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Ravinder Reddy Gaddam
- Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
- Correspondence:
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Pavišić V, Mahmutefendić Lučin H, Blagojević Zagorac G, Lučin P. Arf GTPases Are Required for the Establishment of the Pre-Assembly Compartment in the Early Phase of Cytomegalovirus Infection. Life (Basel) 2021; 11:867. [PMID: 34440611 PMCID: PMC8399710 DOI: 10.3390/life11080867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/31/2022] Open
Abstract
Shortly after entering the cells, cytomegaloviruses (CMVs) initiate massive reorganization of cellular endocytic and secretory pathways, which results in the forming of the cytoplasmic virion assembly compartment (AC). We have previously shown that the formation of AC in murine CMV- (MCMV) infected cells begins in the early phase of infection (at 4-6 hpi) with the pre-AC establishment. Pre-AC comprises membranes derived from the endosomal recycling compartment, early endosomes, and the trans-Golgi network, which is surrounded by fragmented Golgi cisterns. To explore the importance of Arf GTPases in the biogenesis of the pre-AC, we infected Balb 3T3 cells with MCMV and analyzed the expression and intracellular localization of Arf proteins in the early phases (up to 16 hpi) of infection and the development of pre-AC in cells with a knockdown of Arf protein expression by small interfering RNAs (siRNAs). Herein, we show that even in the early phase, MCMVs cause massive reorganization of the Arf system of the host cells and induce the over-recruitment of Arf proteins onto the membranes of pre-AC. Knockdown of Arf1, Arf3, Arf4, or Arf6 impaired the establishment of pre-AC. However, the knockdown of Arf1 and Arf6 also abolished the establishment of infection. Our study demonstrates that Arf GTPases are required for different steps of early cytomegalovirus infection, including the establishment of the pre-AC.
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Affiliation(s)
- Valentino Pavišić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
| | - Hana Mahmutefendić Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Gordana Blagojević Zagorac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Pero Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
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Adarska P, Wong-Dilworth L, Bottanelli F. ARF GTPases and Their Ubiquitous Role in Intracellular Trafficking Beyond the Golgi. Front Cell Dev Biol 2021; 9:679046. [PMID: 34368129 PMCID: PMC8339471 DOI: 10.3389/fcell.2021.679046] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/30/2021] [Indexed: 11/13/2022] Open
Abstract
Molecular switches of the ADP-ribosylation factor (ARF) GTPase family coordinate intracellular trafficking at all sorting stations along the secretory pathway, from the ER-Golgi-intermediate compartment (ERGIC) to the plasma membrane (PM). Their GDP-GTP switch is essential to trigger numerous processes, including membrane deformation, cargo sorting and recruitment of downstream coat proteins and effectors, such as lipid modifying enzymes. While ARFs (in particular ARF1) had mainly been studied in the context of coat protein recruitment at the Golgi, COPI/clathrin-independent roles have emerged in the last decade. Here we review the roles of human ARF1-5 GTPases in cellular trafficking with a particular emphasis on their roles in post-Golgi secretory trafficking and in sorting in the endo-lysosomal system.
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Affiliation(s)
- Petia Adarska
- Institut für Biochemie, Freie Universität Berlin, Berlin, Germany
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