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Fukatsu S, Okawa M, Okabe M, Cho M, Isogai M, Yokoi T, Shirai R, Oizumi H, Yamamoto M, Ohbuchi K, Miyamoto Y, Yamauchi J. Modulating Golgi Stress Signaling Ameliorates Cell Morphological Phenotypes Induced by CHMP2B with Frontotemporal Dementia-Associated p.Asp148Tyr. Curr Issues Mol Biol 2024; 46:1398-1412. [PMID: 38392208 PMCID: PMC10888485 DOI: 10.3390/cimb46020090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/24/2024] Open
Abstract
Some charged multivesicular body protein 2B (CHMP2B) mutations are associated with autosomal-dominant neurodegenerative frontotemporal dementia and/or amyotrophic lateral sclerosis type 7 (FTDALS7). The main aim of this study is to clarify the relationship between the expression of mutated CHMP2B protein displaying FTD symptoms and defective neuronal differentiation. First, we illustrate that the expression of CHMP2B with the Asp148Tyr (D148Y) mutation, which preferentially displays FTD phenotypes, blunts neurite process elongation in rat primary cortical neurons. Similar results were observed in the N1E-115 cell line, a model that undergoes neurite elongation. Second, these effects were also accompanied by changes in neuronal differentiation marker protein expression. Third, wild-type CHMP2B protein was indeed localized in the endosomal sorting complexes required to transport (ESCRT)-like structures throughout the cytoplasm. In contrast, CHMP2B with the D148Y mutation exhibited aggregation-like structures and accumulated in the Golgi body. Fourth, among currently known Golgi stress regulators, the expression levels of Hsp47, which has protective effects on the Golgi body, were decreased in cells expressing CHMP2B with the D148Y mutation. Fifth, Arf4, another Golgi stress-signaling molecule, was increased in mutant-expressing cells. Finally, when transfecting Hsp47 or knocking down Arf4 with small interfering (si)RNA, cellular phenotypes in mutant-expressing cells were recovered. These results suggest that CHMP2B with the D148Y mutation, acting through Golgi stress signaling, is negatively involved in the regulation of neuronal cell morphological differentiation, providing evidence that a molecule controlling Golgi stress may be one of the potential FTD therapeutic targets at the molecular and cellular levels.
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Affiliation(s)
- Shoya Fukatsu
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Maho Okawa
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Miyu Okabe
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Mizuka Cho
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Mikinori Isogai
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Takanori Yokoi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Remina Shirai
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan
| | - Masahiro Yamamoto
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
- Laboratory of Molecular Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
- Laboratory of Molecular Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8506, Japan
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2
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Matsuki T, Hamada N, Ito H, Sugawara R, Iwamoto I, Nakayama A, Nagata KI. Expression analysis of type I ARF small GTPases ARF1-3 during mouse brain development. Mol Biol Rep 2024; 51:106. [PMID: 38227057 DOI: 10.1007/s11033-023-09142-5] [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: 07/12/2023] [Accepted: 12/11/2023] [Indexed: 01/17/2024]
Abstract
BACKGROUND ARF (ADP-ribosylation factor) GTPases are major regulators of intracellular trafficking, and classified into 3 groups (Type I - III), among which the type I group members, ARF1 and 3, are responsible genes for neurodevelopmental disorders. METHODS In this study, we analysed the expression of Type I ARFs ARF1-3 during mouse brain development using biochemical and morphological methods. RESULTS Western blotting analyses revealed that ARF1-3 are weakly expressed in the mouse brain at embryonic day 13 and gradually increase until postnatal day 30. ARF1-3 appear to be abundantly expressed in various telencephalon regions. Biochemical fractionation studies detected ARF1-3 in the synaptosome fraction of cortical neurons containing both pre- and post-synapses, however ARF1-3 were not observed in post-synaptic compartments. In immunohistochemical analyses, ARF1-3 appeared to be distributed in the cytoplasm and dendrites of cortical and hippocampal neurons as well as in the cerebellar molecular layer including dendrites of Purkinje cells and granule cell axons. Immunofluorescence in primary cultured hippocampal neurons revealed that ARF1-3 are diffusely distributed in the cytoplasm and dendrites with partial colocalization with a pre-synaptic marker, synaptophysin. CONCLUSIONS Overall, our results support the notion that ARF1-3 could participate in vesicle trafficking both in the dendritic shaft (excluding spines) and axon terminals (pre-synaptic compartments).
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Affiliation(s)
- Tohru Matsuki
- Department of Cellular Pathology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai, 480-0392, Japan
| | - Nanako Hamada
- Department of Molecular Neurobiology Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai, 480-0392, Japan
| | - Hidenori Ito
- Department of Molecular Neurobiology Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai, 480-0392, Japan
| | - Ryota Sugawara
- Department of Molecular Neurobiology Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai, 480-0392, Japan
| | - Ikuko Iwamoto
- Department of Molecular Neurobiology Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai, 480-0392, Japan
| | - Atsuo Nakayama
- Department of Cellular Pathology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai, 480-0392, Japan
- Department of Neurochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Nagoya, 466-8550, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai, 480-0392, Japan.
- Department of Neurochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Nagoya, 466-8550, Japan.
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Patil RS, Sharma S, Bhaskarwar AV, Nambiar S, Bhat NA, Koppolu MK, Bhukya H. TetR and OmpR family regulators in natural product biosynthesis and resistance. Proteins 2023. [PMID: 37874037 DOI: 10.1002/prot.26621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 08/30/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
This article provides a comprehensive review and sequence-structure analysis of transcription regulator (TR) families, TetR and OmpR/PhoB, involved in specialized secondary metabolite (SSM) biosynthesis and resistance. Transcription regulation is a fundamental process, playing a crucial role in orchestrating gene expression to confer a survival advantage in response to frequent environmental stress conditions. This process, coupled with signal sensing, enables bacteria to respond to a diverse range of intra and extracellular signals. Thus, major bacterial signaling systems use a receptor domain to sense chemical stimuli along with an output domain responsible for transcription regulation through DNA-binding. Sensory and output domains on a single polypeptide chain (one component system, OCS) allow response to stimuli by allostery, that is, DNA-binding affinity modulation upon signal presence/absence. On the other hand, two component systems (TCSs) allow cross-talk between the sensory and output domains as they are disjoint and transmit information by phosphorelay to mount a response. In both cases, however, TRs play a central role. Biosynthesis of SSMs, which includes antibiotics, is heavily regulated by TRs as it diverts the cell's resources towards the production of these expendable compounds, which also have clinical applications. These TRs have evolved to relay information across specific signals and target genes, thus providing a rich source of unique mechanisms to explore towards addressing the rapid escalation in antimicrobial resistance (AMR). Here, we focus on the TetR and OmpR family TRs, which belong to OCS and TCS, respectively. These TR families are well-known examples of regulators in secondary metabolism and are ubiquitous across different bacteria, as they also participate in a myriad of cellular processes apart from SSM biosynthesis and resistance. As a result, these families exhibit higher sequence divergence, which is also evident from our bioinformatic analysis of 158 389 and 77 437 sequences from TetR and OmpR family TRs, respectively. The analysis of both sequence and structure allowed us to identify novel motifs in addition to the known motifs responsible for TR function and its structural integrity. Understanding the diverse mechanisms employed by these TRs is essential for unraveling the biosynthesis of SSMs. This can also help exploit their regulatory role in biosynthesis for significant pharmaceutical, agricultural, and industrial applications.
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Affiliation(s)
- Rachit S Patil
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Siddhant Sharma
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Aditya V Bhaskarwar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Souparnika Nambiar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Niharika A Bhat
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Mani Kanta Koppolu
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Hussain Bhukya
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
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4
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Gujar MR, Gao Y, Teng X, Deng Q, Lin KY, Tan YS, Toyama Y, Wang H. Golgi-dependent reactivation and regeneration of Drosophila quiescent neural stem cells. Dev Cell 2023; 58:1933-1949.e5. [PMID: 37567172 DOI: 10.1016/j.devcel.2023.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 04/26/2023] [Accepted: 07/17/2023] [Indexed: 08/13/2023]
Abstract
The ability of stem cells to switch between quiescent and proliferative states is crucial for maintaining tissue homeostasis and regeneration. In Drosophila, quiescent neural stem cells (qNSCs) extend a primary protrusion, a hallmark of qNSCs. Here, we have found that qNSC protrusions can be regenerated upon injury. This regeneration process relies on the Golgi apparatus that acts as the major acentrosomal microtubule-organizing center in qNSCs. A Golgi-resident GTPase Arf1 and its guanine nucleotide exchange factor Sec71 promote NSC reactivation and regeneration via the regulation of microtubule growth. Arf1 physically associates with its new effector mini spindles (Msps)/XMAP215, a microtubule polymerase. Finally, Arf1 functions upstream of Msps to target the cell adhesion molecule E-cadherin to NSC-neuropil contact sites during NSC reactivation. Our findings have established Drosophila qNSCs as a regeneration model and identified Arf1/Sec71-Msps pathway in the regulation of microtubule growth and NSC reactivation.
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Affiliation(s)
- Mahekta R Gujar
- Neuroscience & Behavioral Disorders Programme, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Yang Gao
- Neuroscience & Behavioral Disorders Programme, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Xiang Teng
- Mechanobiology Institute, Level 5, T-lab Building, 5A Engineering Drive 1, Singapore 117411, Singapore
| | - Qiannan Deng
- Neuroscience & Behavioral Disorders Programme, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Kun-Yang Lin
- Neuroscience & Behavioral Disorders Programme, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Ye Sing Tan
- Neuroscience & Behavioral Disorders Programme, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Yusuke Toyama
- Mechanobiology Institute, Level 5, T-lab Building, 5A Engineering Drive 1, Singapore 117411, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Hongyan Wang
- Neuroscience & Behavioral Disorders Programme, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Integrative Sciences and Engineering Programme, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
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5
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Walton K, Nawara TJ, Angermeier AR, Rosengrant H, Lee E, Wynn B, Victorova E, Belov G, Sztul E. Site-specific phosphorylations of the Arf activator GBF1 differentially regulate GBF1 function in Golgi homeostasis and secretion versus cytokinesis. Sci Rep 2023; 13:13609. [PMID: 37604968 PMCID: PMC10442430 DOI: 10.1038/s41598-023-40705-5] [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: 10/13/2022] [Accepted: 08/16/2023] [Indexed: 08/23/2023] Open
Abstract
Diverse cellular processes, including membrane traffic, lipid homeostasis, cytokinesis, mitochondrial positioning, and cell motility are critically dependent on the Sec7 domain guanine nucleotide exchange factor GBF1. Yet, how the participation of GBF1 in a particular cellular function is regulated is unknown. Here, we show that the phosphorylation of specific highly conserved serine and tyrosine residues within the N-terminal domain of GBF1 differentially regulates its function in maintaining Golgi homeostasis and facilitating secretion versus its role in cytokinesis. Specifically, GBF1 mutants containing single amino acid substitutions that mimic a stably phosphorylated S233, S371, Y377, and Y515 or the S233A mutant that can't be phosphorylated are fully able to maintain Golgi architecture and support cargo traffic through the secretory pathway when assessed in multiple functional assays. However, the same mutants cause multi-nucleation when expressed in cells, and appear to inhibit the progression through mitosis and the resolution of cytokinetic bridges. Thus, GBF1 participates in distinct interactive networks when mediating Golgi homeostasis and secretion versus facilitating cytokinesis, and GBF1 integration into such networks is differentially regulated by the phosphorylation of specific GBF1 residues.
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Affiliation(s)
- Kendall Walton
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, AL, 35233-2008, USA.
| | - Tomasz J Nawara
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, AL, 35233-2008, USA
| | - Allyson R Angermeier
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, AL, 35233-2008, USA
| | - Hadley Rosengrant
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, AL, 35233-2008, USA
| | - Eunjoo Lee
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, AL, 35233-2008, USA
| | - Bridge Wynn
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, AL, 35233-2008, USA
| | - Ekaterina Victorova
- Department of Veterinary Medicine, Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD, 20742, USA
| | - George Belov
- Department of Veterinary Medicine, Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD, 20742, USA
| | - Elizabeth Sztul
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Boulevard, MCLM 668, Birmingham, AL, 35233-2008, USA
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6
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Zhu Y, Wang X, He Z, Zhao P, Ren H, Qi Z. Enterovirus 71 enters human brain microvascular endothelial cells through an ARF6-mediated endocytic pathway. J Med Virol 2023; 95:e28915. [PMID: 37417384 DOI: 10.1002/jmv.28915] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/08/2023] [Accepted: 06/02/2023] [Indexed: 07/08/2023]
Abstract
Infection of the central nervous system caused by enterovirus 71 (EV71) remains the main cause of death in hand-foot-and-mouth disease. However, the mechanism responsible for how EV71 breaks through the blood-brain barrier to infect brain cells has yet to be elucidated. By performing a high-throughput small interfering RNA (siRNA) screening and validation, we found that the infection of human brain microvascular endothelial cells (HBMECs) by EV71 was independent of the endocytosis pathways mediated by caveolin, clathrin, and macropinocytosis but dependent on ADP-ribosylation factor 6 (ARF6), a small guanosinetriphosphate (GTP)-binding protein of the Ras superfamily. The specific siRNA targeting ARF6 markedly inhibited HBMECs susceptibility to EV71. EV71 infectivity was inhibited by NAV-2729, a specific inhibitor of ARF6, in a dose-dependent manner. The subcellular analysis demonstrated the co-localization of the endocytosed EV71 and ARF6, while knockdown of ARF6 with siRNA remarkably influenced EV71 endocytosis. By immunoprecipitation assays, we found a direct interaction of ARF6 with EV71 viral protein. Furthermore, ARF1, another small GTP-binding protein, was also found to participate in ARF6-mediated EV71 endocytosis. Murine experiments demonstrated that NAV-2729 significantly alleviated mortality caused by EV71 infection. Our study revealed a new pathway by which EV71 enters the HBMECs and provides new targets for drug development.
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Affiliation(s)
- Yongzhe Zhu
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai, China
| | - Xiaohang Wang
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai, China
| | - Zhiwei He
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai, China
| | - Ping Zhao
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai, China
| | - Hao Ren
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai, China
| | - Zhongtian Qi
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai, China
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7
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Li FL, Guan KL. The Arf family GTPases: Regulation of vesicle biogenesis and beyond. Bioessays 2023; 45:e2200214. [PMID: 36998106 PMCID: PMC10282109 DOI: 10.1002/bies.202200214] [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: 11/05/2022] [Revised: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 04/01/2023]
Abstract
The Arf family proteins are best known for their roles in the vesicle biogenesis. However, they also play fundamental roles in a wide range of cellular regulation besides vesicular trafficking, such as modulation of lipid metabolic enzymes, cytoskeleton remodeling, ciliogenesis, lysosomal, and mitochondrial morphology and functions. Growing studies continue to expand the downstream effector landscape of Arf proteins, especially for the less-studied members, revealing new biological functions, such as amino acid sensing. Experiments with cutting-edge technologies and in vivo functional studies in the last decade help to provide a more comprehensive view of Arf family functions. In this review, we summarize the cellular functions that are regulated by at least two different Arf members with an emphasis on those beyond vesicle biogenesis.
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Affiliation(s)
- Fu-Long Li
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kun-Liang Guan
- Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
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8
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Yin G, Huang J, Petela J, Jiang H, Zhang Y, Gong S, Wu J, Liu B, Shi J, Gao Y. Targeting small GTPases: emerging grasps on previously untamable targets, pioneered by KRAS. Signal Transduct Target Ther 2023; 8:212. [PMID: 37221195 DOI: 10.1038/s41392-023-01441-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/28/2023] [Accepted: 04/14/2023] [Indexed: 05/25/2023] Open
Abstract
Small GTPases including Ras, Rho, Rab, Arf, and Ran are omnipresent molecular switches in regulating key cellular functions. Their dysregulation is a therapeutic target for tumors, neurodegeneration, cardiomyopathies, and infection. However, small GTPases have been historically recognized as "undruggable". Targeting KRAS, one of the most frequently mutated oncogenes, has only come into reality in the last decade due to the development of breakthrough strategies such as fragment-based screening, covalent ligands, macromolecule inhibitors, and PROTACs. Two KRASG12C covalent inhibitors have obtained accelerated approval for treating KRASG12C mutant lung cancer, and allele-specific hotspot mutations on G12D/S/R have been demonstrated as viable targets. New methods of targeting KRAS are quickly evolving, including transcription, immunogenic neoepitopes, and combinatory targeting with immunotherapy. Nevertheless, the vast majority of small GTPases and hotspot mutations remain elusive, and clinical resistance to G12C inhibitors poses new challenges. In this article, we summarize diversified biological functions, shared structural properties, and complex regulatory mechanisms of small GTPases and their relationships with human diseases. Furthermore, we review the status of drug discovery for targeting small GTPases and the most recent strategic progress focused on targeting KRAS. The discovery of new regulatory mechanisms and development of targeting approaches will together promote drug discovery for small GTPases.
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Affiliation(s)
- Guowei Yin
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China.
| | - Jing Huang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Johnny Petela
- Wake Forest University School of Medicine, Winston-Salem, NC, 27101, USA
| | - Hongmei Jiang
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China
| | - Yuetong Zhang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Siqi Gong
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, China
- School of Medicine, Sun Yat-Sen University, Shenzhen, 518107, China
| | - Jiaxin Wu
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Bei Liu
- National Biomedical Imaging Center, School of Future Technology, Peking University, Beijing, 100871, China
| | - Jianyou Shi
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology, Chengdu, 610072, China.
| | - Yijun Gao
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
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9
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Gulen B, Casey A, Orth K. AMPylation of small GTPases by Fic enzymes. FEBS Lett 2023; 597:883-891. [PMID: 36239538 PMCID: PMC10050140 DOI: 10.1002/1873-3468.14516] [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: 07/06/2022] [Revised: 09/17/2022] [Accepted: 10/06/2022] [Indexed: 12/14/2022]
Abstract
Small GTPases orchestrate numerous cellular pathways, acting as molecular switches and regulatory hubs to transmit molecular signals and because of this, they are often the target of pathogens. During infection, pathogens manipulate host cellular networks using post-translational modifications (PTMs). AMPylation, the modification of proteins with AMP, has been identified as a common PTM utilized by pathogens to hijack GTPase signalling during infection. AMPylation is primarily carried out by enzymes with a filamentation induced by cyclic-AMP (Fic) domain. Modification of small GTPases by AMP renders GTPases impervious to upstream regulatory inputs, resulting in unregulated downstream effector outputs for host cellular processes. Here, we overview Fic-mediated AMPylation of small GTPases by pathogens and other related PTMs catalysed by Fic enzymes on GTPases.
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Affiliation(s)
- Burak Gulen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Amanda Casey
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX and Howard Hughes Medical Institute, Dallas, TX, USA
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10
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Nawrotek A, Dubois P, Zeghouf M, Cherfils J. Molecular principles of bidirectional signalling between membranes and small GTPases. FEBS Lett 2023; 597:778-793. [PMID: 36700390 DOI: 10.1002/1873-3468.14585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/23/2022] [Accepted: 12/30/2022] [Indexed: 01/27/2023]
Abstract
Most small GTPases actuate their functions on subcellular membranes, which are increasingly seen as integral components of small GTPase signalling. In this review, we used the highly studied regulation of Arf GTPases by their GEFs to categorize the molecular principles of membrane contributions to small GTPase signalling, which have been highlighted by integrated structural biology combining in vitro reconstitutions in artificial membranes and high-resolution structures. As an illustration of how this framework can be harnessed to better understand the cooperation between small GTPases, their regulators and membranes, we applied it to the activation of the small GTPase Rac1 by DOCK-ELMO, identifying novel contributions of membranes to Rac1 activation. We propose that these structure-based principles should be considered when interrogating the mechanisms whereby small GTPase systems ensure spatial and temporal control of cellular signalling on membranes.
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Affiliation(s)
- Agata Nawrotek
- CNRS, Ecole Normale Supérieure Paris-Saclay and Université Paris-Saclay, Gif-sur-Yvette, France
| | - Pavlina Dubois
- CNRS, Ecole Normale Supérieure Paris-Saclay and Université Paris-Saclay, Gif-sur-Yvette, France
| | - Mahel Zeghouf
- CNRS, Ecole Normale Supérieure Paris-Saclay and Université Paris-Saclay, Gif-sur-Yvette, France
| | - Jacqueline Cherfils
- CNRS, Ecole Normale Supérieure Paris-Saclay and Université Paris-Saclay, Gif-sur-Yvette, France
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Chidipi B, Chang M, Abou-Assali O, Reiser M, Tian Z, Allen-Gipson D, Noujaim SF. The Arf6/PIP5K pathway activates IKACh in cigarette smoke mediated atrial fibrillation. Cell Signal 2022; 100:110475. [PMID: 36150420 DOI: 10.1016/j.cellsig.2022.110475] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 08/29/2022] [Accepted: 09/16/2022] [Indexed: 11/29/2022]
Abstract
Cigarette smoking (CS) is a major cause of cardiovascular diseases. Smokers are at a significantly higher risk for developing atrial fibrillation (AF), a dangerous and abnormal heart rhythm. In the US, 15.5% of adults are current smokers, and it is becoming clear that CS is an independent risk factor for AF, but a detailed mechanistic understanding of how CS contributes to the molecular patho-electrophysiology of AF remains elusive. We investigated if CS related AF is in part mediated through a mechanism that depends on the cardiac acetylcholine activated inward rectifier potassium current (IKACh). We tested the hypothesis that CS increases IKACh via phosphatidylinositol 4-phosphate 5-kinase alpha (PIP5K) and ADP ribosylation factor 6 (Arf6) signaling, leading to AF perpetuation. In vivo inducibility of AF was assessed in mice exposed to CS for 8 weeks. AF duration was increased in CS exposed mice, and TertiapinQ, an IKACh blocker prevented AF development in CS exposed mice. In HEK293 cells stably transfected with Kir3.1 and Kir3.4, the molecular correlates of IKACh, CS exposure increased the expression of the Kir3.1 and Kir3.4 proteins at the cell surface, activated Arf6 and increased the IKACh current. Inhibition of PIP5K, or of Kir3.1/Kir3.4 trafficking via Arf6 abrogated the CS effects on IKACh. Cigarette smoke modifies the atrial electrophysiological substrate, leading to arrhythmogenesis, in part, through IKACh activation via an Arf6/PIP5K dependent pathway.
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Affiliation(s)
- Bojjibabu Chidipi
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States of America..
| | - Mengmeng Chang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States of America
| | - Obada Abou-Assali
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States of America
| | - Michelle Reiser
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States of America
| | - Zhi Tian
- Department of Pharmaceutical Science, USF Health Taneja College of Pharmacy, University of South Florida, Tampa, FL, United States of America
| | - Diane Allen-Gipson
- Department of Pharmaceutical Science, USF Health Taneja College of Pharmacy, University of South Florida, Tampa, FL, United States of America
| | - Sami F Noujaim
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States of America
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12
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Muccini AJ, Gustafson MA, Fromme JC. Structural basis for activation of Arf1 at the Golgi complex. Cell Rep 2022; 40:111282. [PMID: 36044848 PMCID: PMC9469209 DOI: 10.1016/j.celrep.2022.111282] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/11/2022] [Accepted: 08/05/2022] [Indexed: 11/29/2022] Open
Abstract
The Golgi complex is the central sorting station of the eukaryotic secretory pathway. Traffic through the Golgi requires activation of Arf guanosine triphosphatases that orchestrate cargo sorting and vesicle formation by recruiting an array of effector proteins. Arf activation and Golgi membrane association is controlled by large guanine nucleotide exchange factors (GEFs) possessing multiple conserved regulatory domains. Here we present cryoelectron microscopy (cryoEM) structures of full-length Gea2, the yeast paralog of the human Arf-GEF GBF1, that reveal the organization of these regulatory domains and explain how Gea2 binds to the Golgi membrane surface. We find that the GEF domain adopts two different conformations compatible with different stages of the Arf activation reaction. The structure of a Gea2-Arf1 activation intermediate suggests that the movement of the GEF domain primes Arf1 for membrane insertion upon guanosine triphosphate binding. We propose that conformational switching of Gea2 during the nucleotide exchange reaction promotes membrane insertion of Arf1. Arf1 is a GTPase that regulates Golgi trafficking by recruiting many effector proteins. Muccini et al. report cryoEM structures of the Arf1 activator Gea2, capturing Gea2 in multiple conformational states including a Gea2-Arf1 activation intermediate. The structures help explain how Gea2 activates Arf1 on the Golgi membrane surface.
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Affiliation(s)
- Arnold J Muccini
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Margaret A Gustafson
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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13
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Wang Q, Muhammad TA, Muhammad WH, Muhammad AM, Muhammad H, Yan R, Xu L, Song X, Li X. Hepatocellular carcinoma-associated antigen 59 and ADP-ribosylation factor 1 with poly (lactic-co-glycolic acid): A promising candidate as nanovaccine against haemonchosis. Microb Pathog 2022; 168:105614. [PMID: 35662672 DOI: 10.1016/j.micpath.2022.105614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/04/2022] [Accepted: 05/31/2022] [Indexed: 10/18/2022]
Abstract
Haemonchus contortus (H. contortus) ADP-ribosylation factor 1 (Hc-ARF1) and Hepatocellular carcinoma-associated antigen 59 (Hc-HCA59) are recognized to largely regulate the immune responses of host cells. However, studies about the protective efficacy of the two molecules are poorly unknown. In this research, combinations of recombinant Hc-HCA59 (rHc-HCA59) and Hc-ARF1 (rHc-ARF1) proteins were amalgamated with poly (lactic-co-glycolic acid) (PLGA) nanoparticles adjuvant in order to investigate their protection potential against H. contortus in goats. The results demonstrated that the levels of IgG, IgA, IgE, and IL-4 were noticeably enhanced in the rHc-HCA59 and rHc-ARF1 (rHc-HCA59+rHc-ARF1) group before H. contortus third-stage larvae (L3) challenge. After the L3 challenge, the levels of IL-17, IL-9, and TGF-β were considerably upregulated in the rHc-HCA59+rHc-ARF1 group. In the meantime, the abomasal worm burdens and the fecal eggs were reduced by 63.2% and 69.4% respectively in the rHc-HCA59+rHc-ARF1 group. According to the studies, PLGA nanoparticles immobilized with rHc-HCA59 and rHc-ARF1 proteins conferred partial protection and were expected to be a potential candidate for developing nano vaccines to combat goat haemonchosis.
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Affiliation(s)
- QiangQiang Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - Tahir Aleem Muhammad
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - Waqqas Hasan Muhammad
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - Ali Memon Muhammad
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - Haseeb Muhammad
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - RuoFeng Yan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - LiXin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - XiaoKai Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China
| | - XiangRui Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, PR China.
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14
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Hespen CW, Zhao X, Hang HC. Membrane targeting enhances muramyl dipeptide binding to NOD2 and Arf6-GTPase in mammalian cells. Chem Commun (Camb) 2022; 58:6598-6601. [PMID: 35584401 DOI: 10.1039/d2cc01903e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
To further understand the mechanisms of muramyl dipeptide (MDP) sensing by NOD2, we evaluated key properties involved in the formation of the Arf6-MDP-NOD2 complex in mammalian cells. We found that the conserved Arf aromatic triad is crucial for binding to MDP-NOD2. Mutation of Arf6 N-myristoylation and NOD2 S-palmitoylation also abrogated the formation of the Arf6-MDP-NOD2 complex. Notably, lipid-modified MDP (L18-MDP) increased Arf6-NOD2 assembly. Our results indicate recruitment of Arf6 may explain enhanced activity of lipidated MDP analogues and membrane targeting may be important in developing next-generation NOD2 agonists.
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Affiliation(s)
- Charles W Hespen
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA.
| | - Xiaohui Zhao
- Department of Immunology and Microbiology and Department of Chemistry, Scripps Research, 10550 N Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Howard C Hang
- Department of Immunology and Microbiology and Department of Chemistry, Scripps Research, 10550 N Torrey Pines Rd, La Jolla, CA 92037, USA
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15
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Opalko HE, Miller KE, Kim HS, Vargas-Garcia CA, Singh A, Keogh MC, Moseley JB. Arf6 anchors Cdr2 nodes at the cell cortex to control cell size at division. J Cell Biol 2022; 221:e202109152. [PMID: 34958661 PMCID: PMC8931934 DOI: 10.1083/jcb.202109152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/12/2021] [Accepted: 12/02/2021] [Indexed: 12/25/2022] Open
Abstract
Fission yeast cells prevent mitotic entry until a threshold cell surface area is reached. The protein kinase Cdr2 contributes to this size control system by forming multiprotein nodes that inhibit Wee1 at the medial cell cortex. Cdr2 node anchoring at the cell cortex is not fully understood. Through a genomic screen, we identified the conserved GTPase Arf6 as a component of Cdr2 signaling. Cells lacking Arf6 failed to divide at a threshold surface area and instead shifted to volume-based divisions at increased overall size. Arf6 stably localized to Cdr2 nodes in its GTP-bound but not GDP-bound state, and its guanine nucleotide exchange factor (GEF), Syt22, was required for both Arf6 node localization and proper size at division. In arf6Δ mutants, Cdr2 nodes detached from the membrane and exhibited increased dynamics. These defects were enhanced when arf6Δ was combined with other node mutants. Our work identifies a regulated anchor for Cdr2 nodes that is required for cells to sense surface area.
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Affiliation(s)
- Hannah E. Opalko
- Department of Biochemistry and Cell Biology, the Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Kristi E. Miller
- Department of Biochemistry and Cell Biology, the Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Hyun-Soo Kim
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY
| | - Cesar Augusto Vargas-Garcia
- Grupo de Investigación en Sistemas Agropecuarios Sostenibles, Corporación Colombiana de Investigación Agropecuaria – AGROSAVIA, Bogotá, Colombia
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE
| | | | - James B. Moseley
- Department of Biochemistry and Cell Biology, the Geisel School of Medicine at Dartmouth, Hanover, NH
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16
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Turn RE, Hu Y, Dewees SI, Devi N, East MP, Hardin KR, Khatib T, Linnert J, Wolfrum U, Lim MJ, Casanova JE, Caspary T, Kahn RA. The ARF GAPs ELMOD1 and ELMOD3 act at the Golgi and cilia to regulate ciliogenesis and ciliary protein traffic. Mol Biol Cell 2022; 33:ar13. [PMID: 34818063 PMCID: PMC9236152 DOI: 10.1091/mbc.e21-09-0443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/11/2022] Open
Abstract
ELMODs are a family of three mammalian paralogues that display GTPase-activating protein (GAP) activity toward a uniquely broad array of ADP-ribosylation factor (ARF) family GTPases that includes ARF-like (ARL) proteins. ELMODs are ubiquitously expressed in mammalian tissues, highly conserved across eukaryotes, and ancient in origin, being present in the last eukaryotic common ancestor. We described functions of ELMOD2 in immortalized mouse embryonic fibroblasts (MEFs) in the regulation of cell division, microtubules, ciliogenesis, and mitochondrial fusion. Here, using similar strategies with the paralogues ELMOD1 and ELMOD3, we identify novel functions and locations of these cell regulators and compare them to those of ELMOD2, allowing the determination of functional redundancy among the family members. We found strong similarities in phenotypes resulting from deletion of either Elmod1 or Elmod3 and marked differences from those arising in Elmod2 deletion lines. Deletion of either Elmod1 or Elmod3 results in the decreased ability of cells to form primary cilia, loss of a subset of proteins from cilia, and accumulation of some ciliary proteins at the Golgi, predicted to result from compromised traffic from the Golgi to cilia. These phenotypes are reversed upon activating mutant expression of either ARL3 or ARL16, linking their roles to ELMOD1/3 actions.
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Affiliation(s)
- Rachel E. Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
- Department of Microbiology and Immunology, Stanford University, Palo Alto, CA 94305
| | - Yihan Hu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan, China
| | - Skylar I. Dewees
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Narra Devi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Michael P. East
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Katherine R. Hardin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Tala Khatib
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Joshua Linnert
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Michael J. Lim
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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17
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Miyamoto Y, Torii T, Homma K, Oizumi H, Ohbuchi K, Mizoguchi K, Takashima S, Yamauchi J. The adaptor SH2B1 and the phosphatase PTP4A1 regulate the phosphorylation of cytohesin-2 in myelinating Schwann cells in mice. Sci Signal 2022; 15:eabi5276. [PMID: 35077201 DOI: 10.1126/scisignal.abi5276] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mature myelin sheaths insulate axons to increase nerve conduction velocity and protect nerve fibers from stress and physical injury. In the peripheral nervous system, the myelin sheath is produced by Schwann cells. The guanine-nucleotide exchange factor cytohesin-2 activates the protein Arf6 to promote Schwann cell myelination. Here, we investigated the regulation of cytohesin-2 and found that the phosphorylation status of Tyr381 in cytohesin-2 is central to Schwann cell myelination. Knockin mice with a nonphosphorylatable Y381F mutation in cytohesin-2 exhibited reduced myelin thickness and decreased Arf6 activity in sciatic nerve tissue. In HEK293T cells, cytohesin-2 was dephosphorylated at Tyr381 by the protein tyrosine phosphatase PTP4A1, whereas phosphorylation at this site was maintained by interaction with the adaptor protein SH2B1. Schwann cell-specific knockdown of PTP4A1 in mice increased cytohesin-2 phosphorylation and myelin thickness. Conversely, Schwann cell-specific loss of SH2B1 resulted in reduced myelin thickness and decreased cytohesin-2 phosphorylation. Thus, a signaling unit centered on cytohesin-2-with SH2B1 as a positive regulator and PTP4A1 as a negative regulator-controls Schwann cell myelination in the peripheral nervous system.
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Affiliation(s)
- Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.,Laboratory of Molecular Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Tomohiro Torii
- Laboratory of Ion Channel Pathophysiology, Doshisha University Graduate School of Brain Science, Kyotanabe, Kyoto 610-0394, Japan
| | - Keiichi Homma
- Department of Life Science and Informatics, Maebashi Institute of Technology, Maebashi, Gunma 371-0816, Japan
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki 200-1192, Japan
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki 200-1192, Japan
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki 200-1192, Japan
| | - Shou Takashima
- Laboratory of Glycobiology, The Noguchi Institute, Itabashi, Tokyo 173-0003, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.,Laboratory of Molecular Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
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18
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Chia J, Wang SC, Wee S, Gill DJ, Tay F, Kannan S, Verma CS, Gunaratne J, Bard FA. Src activates retrograde membrane traffic through phosphorylation of GBF1. eLife 2021; 10:68678. [PMID: 34870592 PMCID: PMC8727025 DOI: 10.7554/elife.68678] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 12/05/2021] [Indexed: 12/14/2022] Open
Abstract
The Src tyrosine kinase controls cancer-critical protein glycosylation through Golgi to ER relocation of GALNTs enzymes. How Src induces this trafficking event is unknown. Golgi to ER transport depends on the GTP exchange factor (GEF) GBF1 and small GTPase Arf1. Here, we show that Src induces the formation of tubular transport carriers containing GALNTs. The kinase phosphorylates GBF1 on 10 tyrosine residues; two of them, Y876 and Y898, are located near the C-terminus of the Sec7 GEF domain. Their phosphorylation promotes GBF1 binding to the GTPase; molecular modeling suggests partial melting of the Sec7 domain and intramolecular rearrangement. GBF1 mutants defective for these rearrangements prevent binding, carrier formation, and GALNTs relocation, while phosphomimetic GBF1 mutants induce tubules. In sum, Src promotes GALNTs relocation by promoting GBF1 binding to Arf1. Based on residue conservation, similar regulation of GEF-Arf complexes by tyrosine phosphorylation could be a conserved and widespread mechanism.
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Affiliation(s)
- Joanne Chia
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Shyi-Chyi Wang
- Institute of Molecular and Cell Biology, Singapore, Singapore.,Institute of Bioengineering and Bioimaging, Singapore, Singapore
| | - Sheena Wee
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | | | - Felicia Tay
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | | | - Chandra S Verma
- Bioinformatics Institute, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | | | - Frederic A Bard
- Institute of Molecular and Cell Biology, Singapore, Singapore
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19
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Su MY, Fromm SA, Remis J, Toso DB, Hurley JH. Structural basis for the ARF GAP activity and specificity of the C9orf72 complex. Nat Commun 2021; 12:3786. [PMID: 34145292 PMCID: PMC8213707 DOI: 10.1038/s41467-021-24081-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 05/27/2021] [Indexed: 02/05/2023] Open
Abstract
Mutation of C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontal temporal degeneration (FTD), which is attributed to both a gain and loss of function. C9orf72 forms a complex with SMCR8 and WDR41, which was reported to have GTPase activating protein activity toward ARF proteins, RAB8A, and RAB11A. We determined the cryo-EM structure of ARF1-GDP-BeF3- bound to C9orf72:SMCR8:WDR41. The SMCR8longin and C9orf72longin domains form the binding pocket for ARF1. One face of the C9orf72longin domain holds ARF1 in place, while the SMCR8longin positions the catalytic finger Arg147 in the ARF1 active site. Mutations in interfacial residues of ARF1 and C9orf72 reduced or eliminated GAP activity. RAB8A GAP required ~10-fold higher concentrations of the C9orf72 complex than for ARF1. These data support a specific function for the C9orf72 complex as an ARF GAP. The structure also provides a model for the active forms of the longin domain GAPs of FLCN and NPRL2 that regulate the Rag GTPases of the mTORC1 pathway.
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Affiliation(s)
- Ming-Yuan Su
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Simon A Fromm
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Imaging Centre, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jonathan Remis
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Daniel B Toso
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA.
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20
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Kato Y, Ochiai A, Seki Y, Morimoto T, Oizumi H, Ohbuchi K, Mizoguchi K, Yamamoto M, Sakagami H, Miyamoto Y, Yamauchi J. Phospholipase D and phosphatidylinositol-4-phosphate 5-kinase 1 are involved in the regulation of oligodendrocyte morphological differentiation. Exp Cell Res 2021; 405:112654. [PMID: 34044015 DOI: 10.1016/j.yexcr.2021.112654] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/08/2021] [Accepted: 05/12/2021] [Indexed: 12/30/2022]
Abstract
Oligodendroglial cells (oligodendrocytes) differentiate to form the myelin that wraps neuronal axons in the central nervous system (CNS). This myelin sheath supports the propagation of saltatory conduction and protects axons from physical stresses. When oligodendrocytes do not normally differentiate to myelinate axons, their key functions as oligodendrocytes in the CNS are severely impaired. The molecular mechanics that control differentiation still remain to be clarified. Arf6 belongs to the small GTPase family and is known to be a positive regulator of oligodendrocyte differentiation. Here, we show that the phospholipase D (PLD) and phosphatidylinositol-4-phosphate 5-kinase 1 (PIP5K1) molecules, the major effectors of Arf6, are involved in the regulation of oligodendrocyte differentiation. Knockdown of PLD1 or PIP5K type 1γ (PIP5K1C) by their respective specific siRNAs in mouse oligodendroglial FBD-102b cells inhibited morphological differentiation into structures bearing myelin-like processes; this finding is consistent with the concurrent changes in expression of differentiation and myelin marker proteins. Treatment with VU0155069 or UNC3230, specific inhibitors of PLD and PIP5K1, respectively, blunted morphological differentiation and decreased expression of myelin and differentiation marker proteins. Similar results have been obtained in studies using primary oligodendrocytes. These results suggest that the major Arf6 effector molecules PLD and PIP5K1 are among the molecules involved in the regulation of morphological differentiation in oligodendrocytes prior to myelination.
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Affiliation(s)
- Yukino Kato
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Arisa Ochiai
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Yoichi Seki
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Takako Morimoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki, 200-1192, Japan
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki, 200-1192, Japan
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki, 200-1192, Japan
| | - Masahiro Yamamoto
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki, 200-1192, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, 252-0374, Japan
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan; Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo, 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan; Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo, 157-8535, Japan.
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21
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Small GTPases of the Rab and Arf Families: Key Regulators of Intracellular Trafficking in Neurodegeneration. Int J Mol Sci 2021; 22:ijms22094425. [PMID: 33922618 PMCID: PMC8122874 DOI: 10.3390/ijms22094425] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/14/2021] [Accepted: 04/20/2021] [Indexed: 12/11/2022] Open
Abstract
Small guanosine triphosphatases (GTPases) of the Rab and Arf families are key regulators of vesicle formation and membrane trafficking. Membrane transport plays an important role in the central nervous system. In this regard, neurons require a constant flow of membranes for the correct distribution of receptors, for the precise composition of proteins and organelles in dendrites and axons, for the continuous exocytosis/endocytosis of synaptic vesicles and for the elimination of dysfunctional proteins. Thus, it is not surprising that Rab and Arf GTPases have been associated with neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Both pathologies share characteristics such as the presence of protein aggregates and/or the fragmentation of the Golgi apparatus, hallmarks that have been related to both Rab and Arf GTPases functions. Despite their relationship with neurodegenerative disorders, very few studies have focused on the role of these GTPases in the pathogenesis of neurodegeneration. In this review, we summarize their importance in the onset and progression of Alzheimer’s and Parkinson’s diseases, as well as their emergence as potential therapeutical targets for neurodegeneration.
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22
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Thomas LL, Highland CM, Fromme JC. Arf1 orchestrates Rab GTPase conversion at the trans-Golgi network. Mol Biol Cell 2021; 32:1104-1120. [PMID: 33788577 PMCID: PMC8351538 DOI: 10.1091/mbc.e20-10-0664] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Rab family GTPases are key organizers of membrane trafficking and function as markers of organelle identity. Accordingly, Rab GTPases often occupy specific membrane domains, and mechanisms exist to prevent the inappropriate mixing of distinct Rab domains. The yeast Golgi complex can be divided into two broad Rab domains: Ypt1 (Rab1) and Ypt6 (Rab6) are present at the early/medial Golgi and sharply transition to Ypt31/32 (Rab11) at the late Golgi/trans-Golgi network (TGN). This Rab conversion has been attributed to GTPase-activating protein (GAP) cascades in which Ypt31/32 recruits the Rab-GAPs Gyp1 and Gyp6 to inactivate Ypt1 and Ypt6, respectively. Here we report that Rab transition at the TGN involves additional layers of regulation. We provide new evidence confirming the TRAPPII complex as an important regulator of Ypt6 inactivation and uncover an unexpected role of the Arf1 GTPase in recruiting Gyp1 to drive Ypt1 inactivation at the TGN. Given its established role in directly recruiting TRAPPII to the TGN, Arf1 is therefore a master regulator of Rab conversion on maturing Golgi compartments.
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Affiliation(s)
- Laura L Thomas
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Carolyn M Highland
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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23
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The immunogenic maturation of goat monocyte-derived dendritic cells and upregulation of toll-like receptors by five antigens of Haemonchus contortus in-vitro. Res Vet Sci 2021; 136:247-258. [PMID: 33721712 DOI: 10.1016/j.rvsc.2021.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 12/25/2022]
Abstract
Previously, it was found that several proteins of Haemonchus contortus were involved in the stimulation of the host immune system. However, the information about the selection of superlative antigens with immunogenic efficacies on host DCs is lacking. In the current study, the stimulatory effects of five recombinant proteins (elongation factor-1α, arginine kinase, ES-15, ES-24, and ADP-ribosylation factor 1) of H. contortus on the maturation of goat monocyte-derived dendritic cells (md-DCs) were reported. Recombinant proteins were purified separately in E. coli expression and incubated with isolated goat peripheral blood mononuclear cells (PBMC). Immunofluorescence assay (IFA) results confirmed the binding of these molecules to the md-DC's surface as compared to control groups. In the flow cytometry analysis, recombinant proteins induced md-DC stimulation via the up-regulation of the expression of the costimulatory molecule (CD80) and MHC-II. Quantitative RT-PCR data showed a significant increase in the expression of specific genes of the WNT and toll-like receptor (TLR) signaling pathways. The result of ELISA indicated the higher levels of cytokine (IL-10, IL-12, IFN-γ, and TNF-α) secretion in the md-DC compared to the negative (pET-32a His-Tag) and blank (PBS) control groups. The data gives valuable support in the selection of potential antigens for future studies on the immunomodulation of the host against the infection of H. contortus.
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24
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Tan X, Banerjee P, Pham EA, Rutaganira FUN, Basu K, Bota-Rabassedas N, Guo HF, Grzeskowiak CL, Liu X, Yu J, Shi L, Peng DH, Rodriguez BL, Zhang J, Zheng V, Duose DY, Solis LM, Mino B, Raso MG, Behrens C, Wistuba II, Scott KL, Smith M, Nguyen K, Lam G, Choong I, Mazumdar A, Hill JL, Gibbons DL, Brown PH, Russell WK, Shokat K, Creighton CJ, Glenn JS, Kurie JM. PI4KIIIβ is a therapeutic target in chromosome 1q-amplified lung adenocarcinoma. Sci Transl Med 2021; 12:12/527/eaax3772. [PMID: 31969487 DOI: 10.1126/scitranslmed.aax3772] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 08/14/2019] [Accepted: 10/24/2019] [Indexed: 12/25/2022]
Abstract
Heightened secretion of protumorigenic effector proteins is a feature of malignant cells. Yet, the molecular underpinnings and therapeutic implications of this feature remain unclear. Here, we identify a chromosome 1q region that is frequently amplified in diverse cancer types and encodes multiple regulators of secretory vesicle biogenesis and trafficking, including the Golgi-dedicated enzyme phosphatidylinositol (PI)-4-kinase IIIβ (PI4KIIIβ). Molecular, biochemical, and cell biological studies show that PI4KIIIβ-derived PI-4-phosphate (PI4P) synthesis enhances secretion and accelerates lung adenocarcinoma progression by activating Golgi phosphoprotein 3 (GOLPH3)-dependent vesicular release from the Golgi. PI4KIIIβ-dependent secreted factors maintain 1q-amplified cancer cell survival and influence prometastatic processes in the tumor microenvironment. Disruption of this functional circuitry in 1q-amplified cancer cells with selective PI4KIIIβ antagonists induces apoptosis and suppresses tumor growth and metastasis. These results support a model in which chromosome 1q amplifications create a dependency on PI4KIIIβ-dependent secretion for cancer cell survival and tumor progression.
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Affiliation(s)
- Xiaochao Tan
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Priyam Banerjee
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Edward A Pham
- Departments of Medicine and Microbiology & Immunology, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Florentine U N Rutaganira
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Kaustabh Basu
- Departments of Medicine and Microbiology & Immunology, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Neus Bota-Rabassedas
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Hou-Fu Guo
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Caitlin L Grzeskowiak
- Department of Molecular and Human Genetics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Medicine, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xin Liu
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jiang Yu
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Lei Shi
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - David H Peng
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - B Leticia Rodriguez
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jiaqi Zhang
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Veronica Zheng
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Dzifa Y Duose
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Luisa M Solis
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Barbara Mino
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Maria Gabriela Raso
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Carmen Behrens
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ignacio I Wistuba
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kenneth L Scott
- Department of Molecular and Human Genetics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Medicine, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mark Smith
- Departments of Medicine and Microbiology & Immunology, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Stanford ChEM-H Medicinal Chemistry Knowledge Center, Stanford University, CA 94305, USA
| | - Khanh Nguyen
- Departments of Medicine and Microbiology & Immunology, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Grace Lam
- Departments of Medicine and Microbiology & Immunology, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ingrid Choong
- Departments of Medicine and Microbiology & Immunology, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Abhijit Mazumdar
- Department of Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jamal L Hill
- Department of Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Don L Gibbons
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Powel H Brown
- Department of Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Kevan Shokat
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Chad J Creighton
- Department of Medicine, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA. .,Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jeffrey S Glenn
- Departments of Medicine and Microbiology & Immunology, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA. .,Veterans Administration Medical Center, Palo Alto, CA 94304, USA
| | - Jonathan M Kurie
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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25
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Xie B, Jung C, Chandra M, Engel A, Kendall AK, Jackson LP. The Glo3 GAP crystal structure supports the molecular niche model for ArfGAPs in COPI coats. Adv Biol Regul 2021; 79:100781. [PMID: 33436318 PMCID: PMC7920988 DOI: 10.1016/j.jbior.2020.100781] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/16/2020] [Accepted: 12/21/2020] [Indexed: 11/27/2022]
Abstract
Arf GTPase activating (ArfGAP) proteins are critical regulatory and effector proteins in membrane trafficking pathways. Budding yeast contain two ArfGAP proteins (Gcs1 and Glo3) implicated in COPI coat function at the Golgi, and yeast require Glo3 catalytic function for viability. A new X-ray crystal structure of the Glo3 GAP domain was determined at 2.1 Å resolution using molecular replacement methods. The structure reveals a Cys4-family zinc finger motif with an invariant residue (R59) positioned to act as an "arginine finger" during catalysis. Comparisons among eukaryotic GAP domains show a key difference between ArfGAP1 and ArfGAP2/3 family members in the final helix located within the domain. Conservation at both the sequence and structural levels suggest the Glo3 GAP domain interacts with yeast Arf1 switch I and II regions to promote catalysis. Together, the structural data presented here provide additional evidence for placing Glo3 near Arf1 triads within membrane-assembled COPI coats and further support the molecular niche model for COPI coat regulation by ArfGAPs.
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Affiliation(s)
- Boyang Xie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Christian Jung
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Andrew Engel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Amy K Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.
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26
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Enterovirus Infection Induces Massive Recruitment of All Isoforms of Small Cellular Arf GTPases to the Replication Organelles. J Virol 2020; 95:JVI.01629-20. [PMID: 33087467 DOI: 10.1128/jvi.01629-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/18/2020] [Indexed: 12/12/2022] Open
Abstract
Enterovirus replication requires the cellular protein GBF1, a guanine nucleotide exchange factor for small Arf GTPases. When activated, Arfs associate with membranes, where they regulate numerous steps of membrane homeostasis. The requirement for GBF1 implies that Arfs are important for replication, but which of the different Arfs function(s) during replication remains poorly understood. Here, we established cell lines expressing each of the human Arfs fused to a fluorescent tag and investigated their behavior during enterovirus infection. Arf1 was the first to be recruited to the replication organelles, where it strongly colocalized with the viral antigen 2B and mature virions but not double-stranded RNA. By the end of the infectious cycle, Arf3, Arf4, Arf5, and Arf6 were also concentrated on the replication organelles. Once on the replication membranes, all Arfs except Arf3 were no longer sensitive to inhibition of GBF1, suggesting that in infected cells they do not actively cycle between GTP- and GDP-bound states. Only the depletion of Arf1, but not other class 1 and 2 Arfs, significantly increased the sensitivity of replication to GBF1 inhibition. Surprisingly, depletion of Arf6, a class 3 Arf, normally implicated in plasma membrane events, also increased the sensitivity to GBF1 inhibition. Together, our results suggest that GBF1-dependent Arf1 activation directly supports the development and/or functioning of the replication complexes and that Arf6 plays a previously unappreciated role in viral replication. Our data reveal a complex pattern of Arf activation in enterovirus-infected cells that may contribute to the resilience of viral replication in different cellular environments.IMPORTANCE Enteroviruses include many known and emerging pathogens, such as poliovirus, enteroviruses 71 and D68, and others. However, licensed vaccines are available only against poliovirus and enterovirus 71, and specific anti-enterovirus therapeutics are lacking. Enterovirus infection induces the massive remodeling of intracellular membranes and the development of specialized domains harboring viral replication complexes, replication organelles. Here, we investigated the roles of small Arf GTPases during enterovirus infection. Arfs control distinct steps in intracellular membrane traffic, and one of the Arf-activating proteins, GBF1, is a cellular factor required for enterovirus replication. We found that all Arfs expressed in human cells, including Arf6, normally associated with the plasma membrane, are recruited to the replication organelles and that Arf1 appears to be the most important Arf for enterovirus replication. These results document the rewiring of the cellular membrane pathways in infected cells and may provide new ways of controlling enterovirus infections.
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27
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Protein-membrane interactions in small GTPase signalling and pharmacology: perspectives from Arf GTPases studies. Biochem Soc Trans 2020; 48:2721-2728. [PMID: 33336699 DOI: 10.1042/bst20200482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 11/17/2022]
Abstract
Small GTPases, in association with their GEFs, GAPs and effectors, control major intracellular processes such as signal transduction, cytoskeletal dynamics and membrane trafficking. Accordingly, dysfunctions in their biochemical properties are associated with many diseases, including cancers, diabetes, infections, mental disorders and cardiac diseases, which makes them attractive targets for therapies. However, small GTPases signalling modules are not well-suited for classical inhibition strategies due to their mode of action that combines protein-protein and protein-membrane interactions. As a consequence, there is still no validated drug available on the market that target small GTPases, whether directly or through their regulators. Alternative inhibitory strategies are thus highly needed. Here we review recent studies that highlight the unique modalities of the interaction of small GTPases and their GEFs at the periphery of membranes, and discuss how they can be harnessed in drug discovery.
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28
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Zhang Q, Wang Q, Wu S, Zhang J. Clinical implication and immunological characterisation of the ARF-GEF family member CYTH4 in ovarian cancer. Autoimmunity 2020; 53:434-442. [PMID: 33078956 DOI: 10.1080/08916934.2020.1836487] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND The GTP exchange factors on ADP-ribosylation factor (ARF) mediate the GDP/GTP exchange on ARF, serve as regulators in protein trafficking and membrane dynamics, and play critical roles in various cell processes. However, the relationship between the expression of ARF-GEF family genes and clinical implications in ovarian cancer remains unclear. METHODS We performed a systematic investigation on the role of ARF-GEF family genes in ovarian cancer by using Gene Expression Omnibus (GEO), Kaplan-Meier plotter, Gene set enrichment analysis (GSEA), TIMER and TISIDB database. RESULTS We found that the ARF-GEF family gene CYTH4 exhibited significant expressional upregulation in ovarian cancer compared to normal ovary tissues. The expression of CYTH4 was also higher in metastases from the omentum than in matched primary ovarian tumours. Kaplan-Meier plotter showed that high expression of CYTH4 predicted worse overall survival, progression free survival and post-progression survival of ovarian cancer patients. Notably, from our correlation analysis, CYTH4 expression showed closely association with tumour-infiltrating immune cells. Intriguingly, the expression of CYTH4 was also significantly correlated with a variety of immunomodulators, chemokines and major histocompatibility complex molecules. CONCLUSION Overall, our findings provide a valuable source of data about the clinical significance of CYTH4 in ovarian cancer.
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Affiliation(s)
- Qinyi Zhang
- Department of Obstetrics and Gynecology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qingying Wang
- Department of Obstetrics and Gynecology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Sufang Wu
- Department of Obstetrics and Gynecology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiawen Zhang
- Department of Obstetrics and Gynecology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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29
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Soubias O, Pant S, Heinrich F, Zhang Y, Roy NS, Li J, Jian X, Yohe ME, Randazzo PA, Lösche M, Tajkhorshid E, Byrd RA. Membrane surface recognition by the ASAP1 PH domain and consequences for interactions with the small GTPase Arf1. SCIENCE ADVANCES 2020; 6:6/40/eabd1882. [PMID: 32998886 PMCID: PMC7527224 DOI: 10.1126/sciadv.abd1882] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/04/2020] [Indexed: 05/05/2023]
Abstract
Adenosine diphosphate-ribosylation factor (Arf) guanosine triphosphatase-activating proteins (GAPs) are enzymes that need to bind to membranes to catalyze the hydrolysis of guanosine triphosphate (GTP) bound to the small GTP-binding protein Arf. Binding of the pleckstrin homology (PH) domain of the ArfGAP With SH3 domain, ankyrin repeat and PH domain 1 (ASAP1) to membranes containing phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is key for maximum GTP hydrolysis but not fully understood. By combining nuclear magnetic resonance, neutron reflectometry, and molecular dynamics simulation, we show that binding of multiple PI(4,5)P2 molecules to the ASAP1 PH domain (i) triggers a functionally relevant allosteric conformational switch and (ii) maintains the PH domain in a well-defined orientation, allowing critical contacts with an Arf1 mimic to occur. Our model provides a framework to understand how binding of the ASAP1 PH domain to PI(4,5)P2 at the membrane may play a role in the regulation of ASAP1.
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Affiliation(s)
- Olivier Soubias
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Frank Heinrich
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- NIST Center for Neutron Research, Gaithersburg, MD 20878, USA
| | - Yue Zhang
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Neeladri Sekhar Roy
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jess Li
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marielle E Yohe
- Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mathias Lösche
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
- NIST Center for Neutron Research, Gaithersburg, MD 20878, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - R Andrew Byrd
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA.
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30
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Yang S, Bahl K, Chou HT, Woodsmith J, Stelzl U, Walz T, Nachury MV. Near-atomic structures of the BBSome reveal the basis for BBSome activation and binding to GPCR cargoes. eLife 2020; 9:55954. [PMID: 32510327 PMCID: PMC7311171 DOI: 10.7554/elife.55954] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/08/2020] [Indexed: 02/07/2023] Open
Abstract
Dynamic trafficking of G protein-coupled receptors (GPCRs) out of cilia is mediated by the BBSome. In concert with its membrane recruitment factor, the small GTPase ARL6/BBS3, the BBSome ferries GPCRs across the transition zone, a diffusion barrier at the base of cilia. Here, we present the near-atomic structures of the BBSome by itself and in complex with ARL6GTP, and we describe the changes in BBSome conformation induced by ARL6GTP binding. Modeling the interactions of the BBSome with membranes and the GPCR Smoothened (SMO) reveals that SMO, and likely also other GPCR cargoes, must release their amphipathic helix 8 from the membrane to be recognized by the BBSome.
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Affiliation(s)
- Shuang Yang
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, United States
| | - Kriti Bahl
- Department of Ophthalmology, University of California San Francisco, San Francisco, United States
| | - Hui-Ting Chou
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, United States
| | - Jonathan Woodsmith
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz and BioTechMed-Graz, Graz, Austria
| | - Ulrich Stelzl
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz and BioTechMed-Graz, Graz, Austria
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, United States
| | - Maxence V Nachury
- Department of Ophthalmology, University of California San Francisco, San Francisco, United States
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31
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The NAE Pathway: Autobahn to the Nucleus for Cell Surface Receptors. Cells 2019; 8:cells8080915. [PMID: 31426451 PMCID: PMC6721735 DOI: 10.3390/cells8080915] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/13/2019] [Indexed: 12/19/2022] Open
Abstract
Various growth factors and full-length cell surface receptors such as EGFR are translocated from the cell surface to the nucleoplasm, baffling cell biologists to the mechanisms and functions of this process. Elevated levels of nuclear EGFR correlate with poor prognosis in various cancers. In recent years, nuclear EGFR has been implicated in regulating gene transcription, cell proliferation and DNA damage repair. Different models have been proposed to explain how the receptors are transported into the nucleus. However, a clear consensus has yet to be reached. Recently, we described the nuclear envelope associated endosomes (NAE) pathway, which delivers EGFR from the cell surface to the nucleus. This pathway involves transport, docking and fusion of NAEs with the outer membrane of the nuclear envelope. EGFR is then presumed to be transported through the nuclear pore complex, extracted from membranes and solubilised. The SUN1/2 nuclear envelope proteins, Importin-beta, nuclear pore complex proteins and the Sec61 translocon have been implicated in the process. While this framework can explain the cell surface to nucleus traffic of EGFR and other cell surface receptors, it raises several questions that we consider in this review, together with implications for health and disease.
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The Molecular Architecture of Native BBSome Obtained by an Integrated Structural Approach. Structure 2019; 27:1384-1394.e4. [PMID: 31303482 DOI: 10.1016/j.str.2019.06.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/21/2019] [Accepted: 06/17/2019] [Indexed: 01/09/2023]
Abstract
The unique membrane composition of cilia is maintained by a diffusion barrier at the transition zone that is breached when the BBSome escorts signaling receptors out of cilia. Understanding how the BBSome removes proteins from cilia has been hampered by a lack of structural information. Here, we present a nearly complete Cα model of BBSome purified from cow retina. The model is based on a single-particle cryo-electron microscopy density map at 4.9-Å resolution that was interpreted with the help of comprehensive Rosetta-based structural modeling constrained by crosslinking mass spectrometry data. We find that BBSome subunits have a very high degree of interconnectivity, explaining the obligate nature of the complex. Furthermore, like other coat adaptors, the BBSome exists in an autoinhibited state in solution and must thus undergo a conformational change upon recruitment to membranes by the small GTPase ARL6/BBS3. Our model provides the first detailed view of the machinery enabling ciliary exit.
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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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34
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Wang YC, Westcott NP, Griffin ME, Hang HC. Peptidoglycan Metabolite Photoaffinity Reporters Reveal Direct Binding to Intracellular Pattern Recognition Receptors and Arf GTPases. ACS Chem Biol 2019; 14:405-414. [PMID: 30735346 DOI: 10.1021/acschembio.8b01038] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The peptidoglycan fragments γ-d-glutamyl- meso-diaminopimelic acid (iE-DAP) and muramyl-dipeptide (MDP) are microbial-specific metabolites that activate intracellular pattern recognition receptors and stimulate immune signaling pathways. While extensive structure-activity studies have demonstrated that these bacterial cell wall metabolites trigger NOD1- and NOD2-dependent signaling, their direct binding to these innate immune receptors or other proteins in mammalian cells has not been established. To characterize these fundamental microbial metabolite-host interactions, we synthesized a series of peptidoglycan metabolite photoaffinity reporters and evaluated their cross-linking to NOD1 and NOD2 in mammalian cells. We show that active iE-DAP and MDP photoaffinity reporters selectively cross-linked NOD1 and NOD2, respectively, and not their inactive mutants. We also discovered MDP reporter cross-linking to Arf GTPases, which interacted most prominently with GTP-bound Arf6 and coimmunoprecipitated with NOD2 upon MDP stimulation. Notably, MDP binding to NOD2 and Arf6 was abrogated with loss-of-function NOD2 mutants associated with Crohn's disease. Our studies demonstrate peptidoglycan metabolite photoaffinity reporters can capture their cognate immune receptors in cells and reveal unpredicted ligand-induced interactions with other cellular cofactors. These photoaffinity reporters should afford useful tools to discover and characterize other peptidoglycan metabolite-interacting proteins.
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Affiliation(s)
- Yen-Chih Wang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
| | - Nathan P. Westcott
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
| | - Matthew E. Griffin
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
| | - Howard C. Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
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35
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Small GTPase peripheral binding to membranes: molecular determinants and supramolecular organization. Biochem Soc Trans 2018; 47:13-22. [PMID: 30559268 DOI: 10.1042/bst20170525] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/23/2018] [Accepted: 11/27/2018] [Indexed: 01/26/2023]
Abstract
Small GTPases regulate many aspects of cell logistics by alternating between an inactive, GDP-bound form and an active, GTP-bound form. This nucleotide switch is coupled to a cytosol/membrane cycle, such that GTP-bound small GTPases carry out their functions at the periphery of endomembranes. A global understanding of the molecular determinants of the interaction of small GTPases with membranes and of the resulting supramolecular organization is beginning to emerge from studies of model systems. Recent studies highlighted that small GTPases establish multiple interactions with membranes involving their lipid anchor, their lipididated hypervariable region and elements in their GTPase domain, which combine to determine the strength, specificity and orientation of their association with lipids. Thereby, membrane association potentiates small GTPase interactions with GEFs, GAPs and effectors through colocalization and positional matching. Furthermore, it leads to small GTPase nanoclustering and to lipid demixing, which drives the assembly of molecular platforms in which proteins and lipids co-operate in producing high-fidelity signals through feedback and feedforward loops. Although still fragmentary, these observations point to an integrated model of signaling by membrane-attached small GTPases that involves a diversity of direct and indirect interactions, which can inspire new therapeutic strategies to block their activities in diseases.
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36
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Chen D, Yang C, Liu S, Hang W, Wang X, Chen J, Shi A. SAC-1 ensures epithelial endocytic recycling by restricting ARF-6 activity. J Cell Biol 2018; 217:2121-2139. [PMID: 29563216 PMCID: PMC5987724 DOI: 10.1083/jcb.201711065] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/06/2018] [Accepted: 02/28/2018] [Indexed: 11/22/2022] Open
Abstract
Arf6/ARF-6 is a crucial regulator of the endosomal phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) pool in endocytic recycling. To further characterize ARF-6 regulation, we performed an ARF-6 interactor screen in Caenorhabditis elegans and identified SAC-1, the homologue of the phosphoinositide phosphatase Sac1p in yeast, as a novel ARF-6 partner. In the absence of ARF-6, basolateral endosomes show a loss of SAC-1 staining in epithelial cells. Steady-state cargo distribution assays revealed that loss of SAC-1 specifically affected apical secretory delivery and basolateral recycling. PI(4,5)P2 levels and the endosomal labeling of the ARF-6 effector UNC-16 were significantly elevated in sac-1 mutants, suggesting that SAC-1 functions as a negative regulator of ARF-6. Further analyses revealed an interaction between SAC-1 and the ARF-6-GEF BRIS-1. This interaction outcompeted ARF-6(guanosine diphosphate [GDP]) for binding to BRIS-1 in a concentration-dependent manner. Consequently, loss of SAC-1 promotes the intracellular overlap between ARF-6 and BRIS-1. BRIS-1 knockdown resulted in a significant reduction in PI(4,5)P2 levels in SAC-1-depleted cells. Interestingly, the action of SAC-1 in sequestering BRIS-1 is independent of SAC-1's catalytic activity. Our results suggest that the interaction of SAC-1 with ARF-6 curbs ARF-6 activity by limiting the access of ARF-6(GDP) to its guanine nucleotide exchange factor, BRIS-1.
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Affiliation(s)
- Dan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chao Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Sha Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Weijian Hang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xianghong Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Juan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China .,Institute for Brain Research, Huazhong University of Science and Technology, Wuhan, Hubei, China.,Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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37
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Steiner B, Weber S, Hilbi H. Formation of the Legionella-containing vacuole: phosphoinositide conversion, GTPase modulation and ER dynamics. Int J Med Microbiol 2018; 308:49-57. [DOI: 10.1016/j.ijmm.2017.08.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/06/2017] [Accepted: 08/08/2017] [Indexed: 11/28/2022] Open
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38
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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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39
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Klink BU, Zent E, Juneja P, Kuhlee A, Raunser S, Wittinghofer A. A recombinant BBSome core complex and how it interacts with ciliary cargo. eLife 2017; 6. [PMID: 29168691 PMCID: PMC5700813 DOI: 10.7554/elife.27434] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 11/03/2017] [Indexed: 01/07/2023] Open
Abstract
Cilia are small, antenna-like structures on the surface of eukaryotic cells that harbor a unique set of sensory proteins, including GPCRs and other membrane proteins. The transport of these proteins involves the BBSome, an eight-membered protein complex that is recruited to ciliary membranes by the G-protein Arl6. BBSome malfunction leads to Bardet-Biedl syndrome, a ciliopathy with severe consequences. Short ciliary targeting sequences (CTS) have been identified that trigger the transport of ciliary proteins. However, mechanistic studies that relate ciliary targeting to BBSome binding are missing. Here we used heterologously expressed BBSome subcomplexes to analyze the complex architecture and to investigate the binding of GPCRs and other receptors to the BBSome. A stable heterohexameric complex was identified that binds to GPCRs with interactions that only partially overlap with previously described CTS, indicating a more complex recognition than anticipated. Arl6•GTP does not affect these interactions, suggesting no direct involvement in cargo loading/unloading.
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Affiliation(s)
- Björn Udo Klink
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.,Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Eldar Zent
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Puneet Juneja
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Anne Kuhlee
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Alfred Wittinghofer
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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40
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Sparrer KMJ, Gableske S, Zurenski MA, Parker ZM, Full F, Baumgart GJ, Kato J, Pacheco-Rodriguez G, Liang C, Pornillos O, Moss J, Vaughan M, Gack MU. TRIM23 mediates virus-induced autophagy via activation of TBK1. Nat Microbiol 2017; 2:1543-1557. [PMID: 28871090 PMCID: PMC5658249 DOI: 10.1038/s41564-017-0017-2] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/31/2017] [Indexed: 12/13/2022]
Abstract
Autophagy and interferon (IFN)-mediated innate immunity are critical antiviral defence mechanisms, and recent evidence indicated that tripartite motif (TRIM) proteins are important regulators of both processes. Although the role of TRIM proteins in modulating antiviral cytokine responses has been well established, much less is known about their involvement in autophagy in response to different viral pathogens. Through a targeted RNAi screen examining the relevance of selected TRIM proteins in autophagy induced by herpes simplex virus 1 (HSV-1), encephalomyocarditis virus (EMCV) and influenza A virus (IAV), we identified several TRIM proteins that regulate autophagy in a virus-species-specific manner, as well as a few TRIM proteins that were essential for autophagy triggered by all three viruses and rapamycin, among them TRIM23. TRIM23 was critical for autophagy-mediated restriction of multiple viruses, and this activity was dependent on both its RING E3 ligase and ADP-ribosylation factor (ARF) GTPase activity. Mechanistic studies revealed that unconventional K27-linked auto-ubiquitination of the ARF domain is essential for the GTP hydrolysis activity of TRIM23 and activation of TANK-binding kinase 1 (TBK1) by facilitating its dimerization and ability to phosphorylate the selective autophagy receptor p62. Our work identifies the TRIM23-TBK1-p62 axis as a key component of selective autophagy and further reveals a role for K27-linked ubiquitination in GTPase-dependent TBK1 activation.
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Affiliation(s)
| | - Sebastian Gableske
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Matthew A Zurenski
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Zachary M Parker
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Florian Full
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Gavin J Baumgart
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Jiro Kato
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Gustavo Pacheco-Rodriguez
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Chengyu Liang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Owen Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Joel Moss
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Martha Vaughan
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michaela U Gack
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA.
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41
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Multiple interactions between an Arf/GEF complex and charged lipids determine activation kinetics on the membrane. Proc Natl Acad Sci U S A 2017; 114:11416-11421. [PMID: 28923919 DOI: 10.1073/pnas.1707970114] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Lipidated small GTPases and their regulators need to bind to membranes to propagate actions in the cell, but an integrated understanding of how the lipid bilayer exerts its effect has remained elusive. Here we focused on ADP ribosylation factor (Arf) GTPases, which orchestrate a variety of regulatory functions in lipid and membrane trafficking, and their activation by the guanine-nucleotide exchange factor (GEF) Brag2, which controls integrin endocytosis and cell adhesion and is impaired in cancer and developmental diseases. Biochemical and structural data are available that showed the exceptional efficiency of Arf activation by Brag2 on membranes. We determined the high-resolution crystal structure of unbound Brag2 containing the GEF (Sec7) and membrane-binding (pleckstrin homology) domains, revealing that it has a constitutively active conformation. We used this structure to analyze the interaction of uncomplexed Brag2 and of the myristoylated Arf1/Brag2 complex with a phosphatidylinositol bisphosphate (PIP2) -containing lipid bilayer, using coarse-grained molecular dynamics. These simulations revealed that the system forms a close-packed, oriented interaction with the membrane, in which multiple PIP2 lipids bind the canonical lipid-binding site and unique peripheral sites of the PH domain, the Arf GTPase and, unexpectedly, the Sec7 domain. We cross-validated these predictions by reconstituting the binding and kinetics of Arf and Brag2 in artificial membranes. Our coarse-grained structural model thus suggests that the high efficiency of Brag2 requires interaction with multiple lipids and a well-defined orientation on the membrane, resulting in a local PIP2 enrichment, which has the potential to signal toward the Arf pathway.
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42
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Ayala I, Colanzi A. Mitotic inheritance of the Golgi complex and its role in cell division. Biol Cell 2017; 109:364-374. [PMID: 28799169 DOI: 10.1111/boc.201700032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/04/2017] [Accepted: 08/04/2017] [Indexed: 12/30/2022]
Abstract
The Golgi apparatus plays essential roles in the processing and sorting of proteins and lipids, but it can also act as a signalling hub and a microtubule-nucleation centre. The Golgi complex (GC) of mammalian cells is composed of stacks connected by tubular bridges to form a continuous membranous system. In spite of this structural complexity, the GC is highly dynamic, and this feature becomes particularly evident during mitosis, when the GC undergoes a multi-step disassembly process that allows its correct partitioning and inheritance by daughter cells. Strikingly, different steps of Golgi disassembly control mitotic entry and progression, indicating that cells actively monitor Golgi integrity during cell division. Here, we summarise the basic mechanisms and the molecular players that are involved in Golgi disassembly, focussing in particular on recent studies that have revealed the fundamental signalling pathways that connect Golgi inheritance to mitotic entry and progression.
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Affiliation(s)
- Inmaculada Ayala
- Institute of Protein Biochemistry, National Research Council, Naples, 80131, Italy
| | - Antonino Colanzi
- Institute of Protein Biochemistry, National Research Council, Naples, 80131, Italy
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43
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Chlamydia Hijacks ARF GTPases To Coordinate Microtubule Posttranslational Modifications and Golgi Complex Positioning. mBio 2017; 8:mBio.02280-16. [PMID: 28465429 PMCID: PMC5414008 DOI: 10.1128/mbio.02280-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The intracellular bacterium Chlamydia trachomatis develops in a parasitic compartment called the inclusion. Posttranslationally modified microtubules encase the inclusion, controlling the positioning of Golgi complex fragments around the inclusion. The molecular mechanisms by which Chlamydia coopts the host cytoskeleton and the Golgi complex to sustain its infectious compartment are unknown. Here, using a genetically modified Chlamydia strain, we discovered that both posttranslationally modified microtubules and Golgi complex positioning around the inclusion are controlled by the chlamydial inclusion protein CT813/CTL0184/InaC and host ARF GTPases. CT813 recruits ARF1 and ARF4 to the inclusion membrane, where they induce posttranslationally modified microtubules. Similarly, both ARF isoforms are required for the repositioning of Golgi complex fragments around the inclusion. We demonstrate that CT813 directly recruits ARF GTPases on the inclusion membrane and plays a pivotal role in their activation. Together, these results reveal that Chlamydia uses CT813 to hijack ARF GTPases to couple posttranslationally modified microtubules and Golgi complex repositioning at the inclusion. Chlamydia trachomatis is an important cause of morbidity and a significant economic burden in the world. However, how Chlamydia develops its intracellular compartment, the so-called inclusion, is poorly understood. Using genetically engineered Chlamydia mutants, we discovered that the effector protein CT813 recruits and activates host ADP-ribosylation factor 1 (ARF1) and ARF4 to regulate microtubules. In this context, CT813 acts as a molecular platform that induces the posttranslational modification of microtubules around the inclusion. These cages are then used to reposition the Golgi complex during infection and promote the development of the inclusion. This study provides the first evidence that ARF1 and ARF4 play critical roles in controlling posttranslationally modified microtubules around the inclusion and that Chlamydia trachomatis hijacks this novel function of ARF to reposition the Golgi complex.
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44
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Altan-Bonnet N. Lipid Tales of Viral Replication and Transmission. Trends Cell Biol 2017; 27:201-213. [PMID: 27838086 PMCID: PMC5318230 DOI: 10.1016/j.tcb.2016.09.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 12/22/2022]
Abstract
Positive-strand RNA viruses are the largest group of RNA viruses on Earth and cellular membranes are critical for all aspects of their life cycle, from entry and replication to exit. In particular, membranes serve as platforms for replication and as carriers to transmit these viruses to other cells, the latter either as an envelope surrounding a single virus or as the vesicle containing a population of viruses. Notably, many animal and human viruses appear to induce and exploit phosphatidylinositol 4-phosphate/cholesterol-enriched membranes for replication, whereas many plant and insect-vectored animal viruses utilize phosphatidylethanolamine/cholesterol-enriched membranes for the same purpose; and phosphatidylserine-enriched membrane carriers are widely used by both single and populations of viruses for transmission. Here I discuss the implications for viral pathogenesis and therapeutic development of this remarkable convergence on specific membrane lipid blueprints for replication and transmission.
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Affiliation(s)
- Nihal Altan-Bonnet
- Laboratory of Host-Pathogen Dynamics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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45
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Wang Y, Zhang H, Shi M, Liou YC, Lu L, Yu F. Sec71 functions as a GEF for the small GTPase Arf1 to govern dendrite pruning of Drosophila sensory neurons. Development 2017; 144:1851-1862. [DOI: 10.1242/dev.146175] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/29/2017] [Indexed: 01/20/2023]
Abstract
Pruning, whereby neurons eliminate their exuberant neurites, is central for the maturation of the nervous system. In Drosophila, sensory neurons, ddaCs, selectively prune their larval dendrites without affecting their axons during metamorphosis. However, it is unknown whether the secretory pathway plays a role in dendrite pruning. Here, we show that the small GTPase Arf1, an important regulator of secretory pathway, is specifically required for dendrite pruning of ddaC/D/E sensory neurons but dispensable for apoptosis of ddaF neurons. Analyses of the GTP and GDP-locked forms of Arf1 indicate that the cycling of Arf1 between GDP-bound and GTP-bound forms is essential for dendrite pruning. We further identified Sec71 as a guanine nucleotide exchange factor for Arf1 that preferentially interacts with its GDP-bound form. Like Arf1, Sec71 is also important for dendrite pruning, but not apoptosis, of sensory neurons. Arf1 and Sec71 are interdependent for their localizations on Golgi. Finally, we show that Sec71/Arf1-mediated trafficking process is a prerequisite for Rab5-dependent endocytosis to facilitate endocytosis and degradation of the cell adhesion molecule Neuroglian (Nrg).
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Affiliation(s)
- Yan Wang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore, 117456
| | - Heng Zhang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
| | - Meng Shi
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551
| | - Yih-Cherng Liou
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore, 117456
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551
| | - Fengwei Yu
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore, 117604
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore, 117456
- Neuroscience and Behavioral Disorder Program, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857
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Fischer B, Lüthy K, Paesmans J, De Koninck C, Maes I, Swerts J, Kuenen S, Uytterhoeven V, Verstreken P, Versées W. Skywalker-TBC1D24 has a lipid-binding pocket mutated in epilepsy and required for synaptic function. Nat Struct Mol Biol 2016; 23:965-973. [DOI: 10.1038/nsmb.3297] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 08/25/2016] [Indexed: 01/08/2023]
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47
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Magdeleine M, Gautier R, Gounon P, Barelli H, Vanni S, Antonny B. A filter at the entrance of the Golgi that selects vesicles according to size and bulk lipid composition. eLife 2016; 5. [PMID: 27458799 PMCID: PMC4961469 DOI: 10.7554/elife.16988] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/12/2016] [Indexed: 12/22/2022] Open
Abstract
When small phosphatidylcholine liposomes are added to perforated cells, they bind preferentially to the Golgi suggesting an exceptional avidity of this organelle for curved membranes without stereospecific interactions. We show that the cis golgin GMAP-210 accounts for this property. First, the liposome tethering properties of the Golgi resembles that of the amphipathic lipid-packing sensor (ALPS) motif of GMAP-210: both preferred small (radius < 40 nm) liposomes made of monounsaturated but not saturated lipids. Second, reducing GMAP-210 levels or redirecting its ALPS motif to mitochondria decreased liposome capture by the Golgi. Extensive mutagenesis analysis suggests that GMAP-210 tethers authentic transport vesicles via the same mechanism whereby the ALPS motif senses lipid-packing defects at the vesicle surface through its regularly spaced hydrophobic residues. We conclude that the Golgi uses GMAP-210 as a filter to select transport vesicles according to their size and bulk lipid composition. DOI:http://dx.doi.org/10.7554/eLife.16988.001
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Affiliation(s)
- Maud Magdeleine
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Valbonne, France
| | - Romain Gautier
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Valbonne, France
| | - Pierre Gounon
- Centre Commun de Microscopie Appliquée, Université Côte d'Azur, Nice, France
| | - Hélène Barelli
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Valbonne, France
| | - Stefano Vanni
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Valbonne, France
| | - Bruno Antonny
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Valbonne, France
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48
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Nawrotek A, Zeghouf M, Cherfils J. Allosteric regulation of Arf GTPases and their GEFs at the membrane interface. Small GTPases 2016; 7:283-296. [PMID: 27449855 DOI: 10.1080/21541248.2016.1215778] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Arf GTPases assemble protein complexes on membranes to carry out major functions in cellular traffic. An essential step is their activation by guanine nucleotide exchange factors (GEFs), whose Sec7 domain stimulates GDP/GTP exchange. ArfGEFs form 2 major families: ArfGEFs with DCB, HUS and HDS domains (GBF1 and BIG1/BIG2 in humans), which act at the Golgi; and ArfGEFs with a C-terminal PH domain (cytohesin, EFA6 and BRAG), which function at the plasma membrane and endosomes. In addition, pathogenic bacteria encode an ArfGEF with a unique membrane-binding domain. Here we review the allosteric regulation of Arf GTPases and their GEFs at the membrane interface. Membranes contribute several regulatory layers: at the GTPase level, where activation by GTP is coupled to membrane recruitment by a built-in structural device; at the Sec7 domain, which manipulates this device to ensure that Arf-GTP is attached to membranes; and at the level of non-catalytic ArfGEF domains, which form direct or GTPase-mediated interactions with membranes that enable a spectacular diversity of regulatory regimes. Notably, we show here that membranes increase the efficiency of a large ArfGEF (human BIG1) by 32-fold by interacting directly with its N-terminal DCB and HUS domains. The diversity of allosteric regulatory regimes suggests that ArfGEFs can function in cascades and circuits to modulate the shape, amplitude and duration of Arf signals in cells. Because Arf-like GTPases feature autoinhibitory elements similar to those of Arf GTPases, we propose that their activation also requires allosteric interactions of these elements with membranes or other proteins.
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Affiliation(s)
- Agata Nawrotek
- a Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure de Cachan and Université Paris-Saclay , Cachan , France
| | - Mahel Zeghouf
- a Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure de Cachan and Université Paris-Saclay , Cachan , France
| | - Jacqueline Cherfils
- a Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure de Cachan and Université Paris-Saclay , Cachan , France
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49
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Galindo A, Soler N, McLaughlin SH, Yu M, Williams RL, Munro S. Structural Insights into Arl1-Mediated Targeting of the Arf-GEF BIG1 to the trans-Golgi. Cell Rep 2016; 16:839-50. [PMID: 27373159 PMCID: PMC4956616 DOI: 10.1016/j.celrep.2016.06.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 05/09/2016] [Accepted: 06/02/2016] [Indexed: 11/28/2022] Open
Abstract
The GTPase Arf1 is the major regulator of vesicle traffic at both the cis- and trans-Golgi. Arf1 is activated at the cis-Golgi by the guanine nucleotide exchange factor (GEF) GBF1 and at the trans-Golgi by the related GEF BIG1 or its paralog, BIG2. The trans-Golgi-specific targeting of BIG1 and BIG2 depends on the Arf-like GTPase Arl1. We find that Arl1 binds to the dimerization and cyclophilin binding (DCB) domain in BIG1 and report a crystal structure of human Arl1 bound to this domain. Residues in the DCB domain that bind Arl1 are required for BIG1 to locate to the Golgi in vivo. DCB domain-binding residues in Arl1 have a distinct conformation from those in known Arl1-effector complexes, and this plasticity allows Arl1 to interact with different effectors of unrelated structure. The findings provide structural insight into how Arf1 GEFs, and hence active Arf1, achieve their correct subcellular distribution.
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Affiliation(s)
- Antonio Galindo
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Nicolas Soler
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Stephen H McLaughlin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Minmin Yu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Roger L Williams
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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50
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Shen QT, Ren X, Zhang R, Lee IH, Hurley JH. HIV-1 Nef hijacks clathrin coats by stabilizing AP-1:Arf1 polygons. Science 2016; 350:aac5137. [PMID: 26494761 DOI: 10.1126/science.aac5137] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The lentiviruses HIV and simian immunodeficiency virus (SIV) subvert intracellular membrane traffic as part of their replication cycle. The lentiviral Nef protein helps viruses evade innate and adaptive immune defenses by hijacking the adaptor protein 1 (AP-1) and AP-2 clathrin adaptors. We found that HIV-1 Nef and the guanosine triphosphatase Arf1 induced trimerization and activation of AP-1. Here we report the cryo-electron microscopy structures of the Nef- and Arf1-bound AP-1 trimer in the active and inactive states. A central nucleus of three Arf1 molecules organizes the trimers. We combined the open trimer with a known dimer structure and thus predicted a hexagonal assembly with inner and outer faces that bind the membranes and clathrin, respectively. Hexagons were directly visualized and the model validated by reconstituting clathrin cage assembly. Arf1 and Nef thus play interconnected roles in allosteric activation, cargo recruitment, and coat assembly, revealing an unexpectedly intricate organization of the inner AP-1 layer of the clathrin coat.
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Affiliation(s)
- Qing-Tao Shen
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xuefeng Ren
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Rui Zhang
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Il-Hyung Lee
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - James H Hurley
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA. Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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