1
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Zhu H, Sydor AM, Boddy KC, Coyaud E, Laurent EMN, Au A, Tan JMJ, Yan BR, Moffat J, Muise AM, Yip CM, Grinstein S, Raught B, Brumell JH. Salmonella exploits membrane reservoirs for invasion of host cells. Nat Commun 2024; 15:3120. [PMID: 38600106 PMCID: PMC11006906 DOI: 10.1038/s41467-024-47183-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 03/22/2024] [Indexed: 04/12/2024] Open
Abstract
Salmonella utilizes a type 3 secretion system to translocate virulence proteins (effectors) into host cells during infection1. The effectors modulate host cell machinery to drive uptake of the bacteria into vacuoles, where they can establish an intracellular replicative niche. A remarkable feature of Salmonella invasion is the formation of actin-rich protuberances (ruffles) on the host cell surface that contribute to bacterial uptake. However, the membrane source for ruffle formation and how these bacteria regulate membrane mobilization within host cells remains unclear. Here, we show that Salmonella exploits membrane reservoirs for the generation of invasion ruffles. The reservoirs are pre-existing tubular compartments associated with the plasma membrane (PM) and are formed through the activity of RAB10 GTPase. Under normal growth conditions, membrane reservoirs contribute to PM homeostasis and are preloaded with the exocyst subunit EXOC2. During Salmonella invasion, the bacterial effectors SipC, SopE2, and SopB recruit exocyst subunits from membrane reservoirs and other cellular compartments, thereby allowing exocyst complex assembly and membrane delivery required for bacterial uptake. Our findings reveal an important role for RAB10 in the establishment of membrane reservoirs and the mechanisms by which Salmonella can exploit these compartments during host cell invasion.
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Affiliation(s)
- Hongxian Zhu
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Andrew M Sydor
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
| | - Kirsten C Boddy
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Etienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Protéomique, Réponse Inflammatoire, Spectrométrie de Masse (PRISM)-U1192, Université de Lille, Inserm, CHU Lille, Lille, France
| | - Estelle M N Laurent
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Protéomique, Réponse Inflammatoire, Spectrométrie de Masse (PRISM)-U1192, Université de Lille, Inserm, CHU Lille, Lille, France
| | - Aaron Au
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Joel M J Tan
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
| | - Bing-Ru Yan
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
| | - Jason Moffat
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, ON, Canada
| | - Aleixo M Muise
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Hospital for Sick Children, Toronto, ON, Canada
- SickKids IBD Centre, Hospital for Sick Children, Toronto, ON, Canada
| | - Christopher M Yip
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - John H Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
- SickKids IBD Centre, Hospital for Sick Children, Toronto, ON, Canada.
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2
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Niedziółka SM, Datta S, Uśpieński T, Baran B, Skarżyńska W, Humke EW, Rohatgi R, Niewiadomski P. The exocyst complex and intracellular vesicles mediate soluble protein trafficking to the primary cilium. Commun Biol 2024; 7:213. [PMID: 38378792 PMCID: PMC10879184 DOI: 10.1038/s42003-024-05817-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
The efficient transport of proteins into the primary cilium is a crucial step for many signaling pathways. Dysfunction of this process can lead to the disruption of signaling cascades or cilium assembly, resulting in developmental disorders and cancer. Previous studies on the protein delivery to the cilium were mostly focused on the membrane-embedded receptors. In contrast, how soluble proteins are delivered into the cilium is poorly understood. In our work, we identify the exocyst complex as a key player in the ciliary trafficking of soluble Gli transcription factors. In line with the known function of the exocyst in intracellular vesicle transport, we demonstrate that soluble proteins, including Gli2/3 and Lkb1, can use the endosome recycling machinery for their delivery to the primary cilium. Finally, we identify GTPases: Rab14, Rab18, Rab23, and Arf4 that are involved in vesicle-mediated Gli protein ciliary trafficking. Our data pave the way for a better understanding of ciliary transport and uncover transport mechanisms inside the cell.
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Affiliation(s)
- S M Niedziółka
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - S Datta
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - T Uśpieński
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - B Baran
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - W Skarżyńska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - E W Humke
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- IGM Biosciences, Inc, Mountain View, CA, USA
| | - R Rohatgi
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - P Niewiadomski
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
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3
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Guleria VS, Quadri N, Prasad K, Das R, Upadhyai P. Early insights into the role of Exoc6B associated with spondyloepimetaphyseal dysplasia with joint laxity type 3 in primary ciliogenesis and chondrogenic differentiation in vitro. Mol Biol Rep 2024; 51:274. [PMID: 38305850 DOI: 10.1007/s11033-023-09114-9] [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: 05/15/2023] [Accepted: 12/06/2023] [Indexed: 02/03/2024]
Abstract
BACKGROUND Spondyloepimetaphyseal dysplasia with joint laxity type 3 (SEMDJL3) is a rare skeletal dysplasia associated with EXOC6B, a component of the exocyst complex, involved in vesicle tethering and exocytosis at the plasma membrane. So far, EXOC6B and the pathomechanisms underlying SEMDJL3 remain obscure. METHODS AND RESULTS Exoc6b was detected largely at the perinuclear regions and the primary cilia base in ATDC5 prechondrocytes. Its shRNA lentiviral knockdown impeded primary ciliogenesis. In Exoc6b silenced prechondrocytes, Hedgehog signaling was attenuated, including when stimulated with Smoothened agonist. Exoc6b knockdown deregulated the mRNA and protein levels of Col2a1, a marker of chondrocyte proliferation at 7- and 14-days following differentiation. It led to the upregulation of Ihh another marker of proliferative chondrocytes. The levels of Col10a1, a marker of chondrocyte hypertrophy was enhanced at 14 days of differentiation. Congruently, Axin2, a canonical Wnt pathway modulator that inhibits chondrocyte hypertrophy was repressed. The expression of Mmp13 and Adamts4 that are terminal chondrocyte hypertrophy markers involved in extracellular matrix (ECM) remodelling were downregulated at 7 and 14 days of chondrogenesis. Bglap that encodes for the most abundant non-collagenous bone matrix constituent and promotes ECM calcification was suppressed at 14 days of chondrocyte differentiation. ECM mineralization was assessed by Alizarin Red staining. Gene expression and ciliogenesis were investigated by reverse transcription quantitative real-time PCR, immunoblotting, and immunocytochemistry. CONCLUSIONS These findings provide initial insights into the potential role of Exoc6b in primary ciliogenesis and chondrogenic differentiation, contributing towards a preliminary understanding of the molecular pathomechanisms underlying SEMDJL3.
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Affiliation(s)
- Vishal Singh Guleria
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Neha Quadri
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Keshava Prasad
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Ranajit Das
- Division of Data Analytics, Bioinformatics and Structural Biology, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Priyanka Upadhyai
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India.
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Hinsch CL, Venkata JK, Hsu T, Dammai V. Controlled Plasma Membrane Delivery of FGFR1 and Modulation of Signaling by a Novel Regulated Anterograde RTK Transport Pathway. Cancers (Basel) 2023; 15:5837. [PMID: 38136383 PMCID: PMC10741464 DOI: 10.3390/cancers15245837] [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: 10/19/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
How human FGFR1 localizes to the PM is unknown. Currently, it is assumed that newly synthesized FGFR1 is continuously delivered to the PM. However, evidence indicates that FGFR1 is mostly sequestered in intracellular post-Golgi vesicles (PGVs) under normal conditions. In this report, live-cell imaging and total internal reflection fluorescence microscopy (TIRFM) were employed to study the dynamics of these FGFR1-positive vesicles. We designed recombinant proteins to target different transport components to and from the FGFR1 vesicles. Mouse embryoid bodies (mEBs) were used as a 3D model system to confirm major findings. Briefly, we found that Rab2a, Rab6a, Rab8a, RalA and caveolins are integral components of FGFR1-positive vesicles, representing a novel compartment. While intracellular sequestration prevented FGFR1 activation, serum starvation and hypoxia stimulated PM localization of FGFR1. Under these conditions, FGFR1 C-terminus acts as a scaffold to assemble proteins to (i) inactivate Rab2a and release sequestration, and (ii) assemble Rab6a for localized activation of Rab8a and RalA-exocyst to deliver the receptor to the PM. This novel pathway is named Regulated Anterograde RTK Transport (RART). This is the first instance of RTK regulated through control of PM delivery.
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Affiliation(s)
- Claire Leist Hinsch
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29401, USA (J.K.V.)
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29401, USA
| | - Jagadish Kummetha Venkata
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29401, USA (J.K.V.)
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29401, USA
| | - Tien Hsu
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40433, Taiwan
| | - Vincent Dammai
- Aldevron LLC (Danaher Corporation), Fargo, ND 58104, USA
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5
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De la Concepcion JC. The exocyst complex is an evolutionary battleground in plant-microbe interactions. CURRENT OPINION IN PLANT BIOLOGY 2023; 76:102482. [PMID: 37924562 DOI: 10.1016/j.pbi.2023.102482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/03/2023] [Accepted: 10/05/2023] [Indexed: 11/06/2023]
Abstract
Exocytosis is a conserved trafficking pathway that transports secretory vesicles to the extracellular space, replenishes the plasma membrane and is essential for establishing cell polarity. Its spatiotemporal regulation is mediated by an evolutionary conserved octameric tethering complex, the exocyst. In plants, certain subunits of this complex have diversified and acquired multiple functions, including a central role in defense against pathogens and pests. Here, I review the latest evidence suggesting the dramatic expansion and functional diversification of the exocyst subunit Exo70 is likely driven by a coevolutionary arms race, in which Exo70 proteins are repeatedly targeted by effectors from multiple pathogens and, in turn, are monitored by plant immune receptors for pathogen perception.
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6
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Liu DA, Tao K, Wu B, Yu Z, Szczepaniak M, Rames M, Yang C, Svitkina T, Zhu Y, Xu F, Nan X, Guo W. A phosphoinositide switch mediates exocyst recruitment to multivesicular endosomes for exosome secretion. Nat Commun 2023; 14:6883. [PMID: 37898620 PMCID: PMC10613218 DOI: 10.1038/s41467-023-42661-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 10/17/2023] [Indexed: 10/30/2023] Open
Abstract
Exosomes are secreted to the extracellular milieu when multivesicular endosomes (MVEs) dock and fuse with the plasma membrane. However, MVEs are also known to fuse with lysosomes for degradation. How MVEs are directed to the plasma membrane for exosome secretion rather than to lysosomes is unclear. Here we report that a conversion of phosphatidylinositol-3-phosphate (PI(3)P) to phosphatidylinositol-4-phosphate (PI(4)P) catalyzed sequentially by Myotubularin 1 (MTM1) and phosphatidylinositol 4-kinase type IIα (PI4KIIα) on the surface of MVEs mediates the recruitment of the exocyst complex. The exocyst then targets the MVEs to the plasma membrane for exosome secretion. We further demonstrate that disrupting PI(4)P generation or exocyst function blocked exosomal secretion of Programmed death-ligand 1 (PD-L1), a key immune checkpoint protein in tumor cells, and led to its accumulation in lysosomes. Together, our study suggests that the PI(3)P to PI(4)P conversion on MVEs and the recruitment of the exocyst direct the exocytic trafficking of MVEs for exosome secretion.
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Affiliation(s)
- Di-Ao Liu
- Department of Biology, School of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Kai Tao
- Program in Quantitative and Systems Biology, Department of Biomedical Engineering, Oregon Health and Science University, 2730 S. Moody Ave, Portland, OR, 97201, USA
| | - Bin Wu
- Department of Biology, School of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ziyan Yu
- Department of Biology, School of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Malwina Szczepaniak
- Program in Quantitative and Systems Biology, Department of Biomedical Engineering, Oregon Health and Science University, 2730 S. Moody Ave, Portland, OR, 97201, USA
| | - Matthew Rames
- Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, 2720 S. Moody Ave., Portland, OR, 97201, USA
| | - Changsong Yang
- Department of Biology, School of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Tatyana Svitkina
- Department of Biology, School of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yueyao Zhu
- Department of Biology, School of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA, 19104, USA
| | - Fengyuan Xu
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Xiaolin Nan
- Program in Quantitative and Systems Biology, Department of Biomedical Engineering, Oregon Health and Science University, 2730 S. Moody Ave, Portland, OR, 97201, USA
- Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, 2720 S. Moody Ave., Portland, OR, 97201, USA
| | - Wei Guo
- Department of Biology, School of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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7
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Cheng Z, Zheng Y, Yang W, Sun H, Zhou F, Huang C, Zhang S, Song Y, Liang Q, Yang N, Li M, Liu B, Feng L, Wang L. Pathogenic bacteria exploit transferrin receptor transcytosis to penetrate the blood-brain barrier. Proc Natl Acad Sci U S A 2023; 120:e2307899120. [PMID: 37733740 PMCID: PMC10523449 DOI: 10.1073/pnas.2307899120] [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: 05/11/2023] [Accepted: 08/23/2023] [Indexed: 09/23/2023] Open
Abstract
The human blood-brain barrier (BBB) comprises a single layer of brain microvascular endothelial cells (HBMECs) protecting the brain from bloodborne pathogens. Meningitis is among the most serious diseases, but the mechanisms by which major meningitis-causing bacterial pathogens cross the BBB to reach the brain remain poorly understood. We found that Streptococcus pneumoniae, group B Streptococcus, and neonatal meningitis Escherichia coli commonly exploit a unique vesicle fusion mechanism to hitchhike on transferrin receptor (TfR) transcytosis to cross the BBB and illustrated the details of this process in human BBB model in vitro and mouse model. Toll-like receptor signals emanating from bacteria-containing vesicles (BCVs) trigger K33-linked polyubiquitination at Lys168 and Lys181 of the innate immune regulator TRAF3 and then activate the formation of a protein complex containing the guanine nucleotide exchange factor RCC2, the small GTPase RalA and exocyst subcomplex I (SC I) on BCVs. The distinct function of SEC6 in SC I, interacting directly with RalA on BCVs and the SNARE protein SNAP23 on TfR vesicles, tethers these two vesicles and initiates the fusion. Our results reveal that innate immunity triggers a unique modification of TRAF3 and the formation of the HBMEC-specific protein complex on BCVs to authenticate the precise recognition and selection of TfR vesicles to fuse with and facilitate bacterial penetration of the BBB.
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Affiliation(s)
- Zhihui Cheng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Yangyang Zheng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Wen Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Hongmin Sun
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Fangyu Zhou
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Chuangjie Huang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Shuwen Zhang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Yingying Song
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Qi’an Liang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Nan Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Meifang Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin300071, China
| | - Bin Liu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Lu Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
| | - Lei Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin300071, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin300457, China
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8
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Reyes A, Hatcher JD, Salazar E, Galan J, Iliuk A, Sanchez EE, Suntravat M. Proteomic Profiling of Extracellular Vesicles Isolated from Plasma and Peritoneal Exudate in Mice Induced by Crotalus scutulatus scutulatus Crude Venom and Its Purified Cysteine-Rich Secretory Protein (Css-CRiSP). Toxins (Basel) 2023; 15:434. [PMID: 37505703 PMCID: PMC10467150 DOI: 10.3390/toxins15070434] [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: 05/27/2023] [Revised: 06/23/2023] [Accepted: 06/29/2023] [Indexed: 07/29/2023] Open
Abstract
Increased vascular permeability is a frequent outcome of viperid snakebite envenomation, leading to local and systemic complications. We reported that snake venom cysteine-rich secretory proteins (svCRiSPs) from North American pit vipers increase vascular permeability both in vitro and in vivo. They also induce acute activation of several adhesion and signaling molecules that may play a critical role in the pathophysiology of snakebites. Extracellular vesicles (EVs) have gained interest for their diverse functions in intercellular communication, regulating cellular processes, blood-endothelium interactions, vascular permeability, and immune modulation. They also hold potential as valuable biomarkers for diagnosing, predicting, and monitoring therapeutic responses in different diseases. This study aimed to identify proteins in peritoneal exudate and plasma EVs isolated from BALB/c mice following a 30 min post-injection of Crotalus scutulatus scutulatus venom and its purified CRiSP (Css-CRiSP). EVs were isolated from these biofluids using the EVtrap method. Proteomic analysis of exudate- and plasma-derived EVs was performed using LC-MS/MS. We observed significant upregulation or downregulation of proteins involved in cell adhesion, cytoskeleton rearrangement, signal transduction, immune responses, and vesicle-mediated transports. These findings suggest that svCRiSPs play a crucial role in the acute effects of venom and contribute to the local and systemic toxicity of snakebites.
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Affiliation(s)
- Armando Reyes
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA; (A.R.); (J.D.H.); (E.S.); (E.E.S.)
| | - Joseph D. Hatcher
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA; (A.R.); (J.D.H.); (E.S.); (E.E.S.)
| | - Emelyn Salazar
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA; (A.R.); (J.D.H.); (E.S.); (E.E.S.)
| | - Jacob Galan
- Department of Human Genetics, The University of Texas Rio Grande Valley School of Medicine, Brownsville, TX 78539, USA;
| | - Anton Iliuk
- Tymora Analytical Operations, West Lafayette, IN 47906, USA;
| | - Elda E. Sanchez
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA; (A.R.); (J.D.H.); (E.S.); (E.E.S.)
- Department of Chemistry, Texas A&M University-Kingsville, MSC 161, Kingsville, TX 78363, USA
| | - Montamas Suntravat
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA; (A.R.); (J.D.H.); (E.S.); (E.E.S.)
- Department of Chemistry, Texas A&M University-Kingsville, MSC 161, Kingsville, TX 78363, USA
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9
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Logue MJE, Farquhar RE, Eckhoff-Björngard Y, Cheung TT, Devor DC, McDonald FJ, Hamilton KL. The exocyst complex is required for the trafficking and delivery of KCa3.1 to the basolateral membrane of polarized epithelia. Am J Physiol Cell Physiol 2023; 324:C1249-C1262. [PMID: 37125772 PMCID: PMC10243536 DOI: 10.1152/ajpcell.00374.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 05/02/2023]
Abstract
Control of the movement of ions and water across epithelia is essential for homeostasis. Changing the number or activity of ion channels at the plasma membrane is a significant regulator of epithelial transport. In polarized epithelia, the intermediate-conductance calcium-activated potassium channel, KCa3.1 is delivered to the basolateral membrane where it generates and maintains the electrochemical gradients required for epithelial transport. The mechanisms that control the delivery of KCa3.1 to the basolateral membrane are still emerging. Herein, we investigated the role of the highly conserved tethering complex exocyst. In epithelia, exocyst is involved in the tethering of post-Golgi secretory vesicles with the basolateral membrane, which is required before membrane fusion. In our Fisher rat thyroid cell line that stably expresses KCa3.1, siRNA knockdown of either of the exocyst subunits Sec3, Sec6, or Sec8 significantly decreased KCa3.1-specific current. In addition, knockdown of exocyst complex subunits significantly reduced the basolateral membrane protein level of KCa3.1. Finally, co-immunoprecipitation experiments suggest associations between Sec6 and KCa3.1, but not between Sec8 and KCa3.1. Collectively, based on these data and our previous studies, we suggest that components of exocyst complex are crucially important in the tethering of KCa3.1 to the basolateral membrane. After which, Soluble N-ethylmaleimide-sensitive factor (SNF) Attachment Receptors (SNARE) proteins aid in the insertion of KCa3.1-containing vesicles into the basolateral membrane of polarized epithelia.NEW & NOTEWORTHY Our Ussing chamber and immunoblot experiments demonstrate that when subunits of the exocyst complex were transiently knocked down, this significantly reduced the basolateral population and functional expression of KCa3.1. These data suggest, combined with our protein association experiments, that the exocyst complex regulates the tethering of KCa3.1-containing vesicles to the basolateral membrane prior to the SNARE-dependent insertion of channels into the basolateral membrane of epithelial cells.
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Affiliation(s)
- Matthew J E Logue
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Rachel E Farquhar
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Yoakim Eckhoff-Björngard
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Tanya T Cheung
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Daniel C Devor
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Kirk L Hamilton
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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10
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Pereira C, Stalder D, Anderson GS, Shun-Shion AS, Houghton J, Antrobus R, Chapman MA, Fazakerley DJ, Gershlick DC. The exocyst complex is an essential component of the mammalian constitutive secretory pathway. J Cell Biol 2023; 222:e202205137. [PMID: 36920342 PMCID: PMC10041652 DOI: 10.1083/jcb.202205137] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/11/2022] [Accepted: 02/01/2023] [Indexed: 03/16/2023] Open
Abstract
Secreted proteins fulfill a vast array of functions, including immunity, signaling, and extracellular matrix remodeling. In the trans-Golgi network, proteins destined for constitutive secretion are sorted into post-Golgi carriers which fuse with the plasma membrane. The molecular machinery involved is poorly understood. Here, we have used kinetic trafficking assays and transient CRISPR-KO to study biosynthetic sorting from the Golgi to the plasma membrane. Depletion of all canonical exocyst subunits causes cargo accumulation in post-Golgi carriers. Exocyst subunits are recruited to and co-localize with carriers. Exocyst abrogation followed by kinetic trafficking assays of soluble cargoes results in intracellular cargo accumulation. Unbiased secretomics reveals impairment of soluble protein secretion after exocyst subunit knockout. Importantly, in specialized cell types, the loss of exocyst prevents constitutive secretion of antibodies in lymphocytes and of leptin in adipocytes. These data identify exocyst as the functional tether of secretory post-Golgi carriers at the plasma membrane and an essential component of the mammalian constitutive secretory pathway.
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Affiliation(s)
- Conceição Pereira
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Danièle Stalder
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Amber S. Shun-Shion
- Metabolic Research Laboratory, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Jack Houghton
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Daniel J. Fazakerley
- Metabolic Research Laboratory, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - David C. Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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11
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Barbosa ICR, De Bellis D, Flückiger I, Bellani E, Grangé-Guerment M, Hématy K, Geldner N. Directed growth and fusion of membrane-wall microdomains requires CASP-mediated inhibition and displacement of secretory foci. Nat Commun 2023; 14:1626. [PMID: 36959183 PMCID: PMC10036488 DOI: 10.1038/s41467-023-37265-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 03/07/2023] [Indexed: 03/25/2023] Open
Abstract
Casparian strips (CS) are aligned bands of lignin-impregnated cell walls, building an extracellular diffusion barrier in roots. Their structure profoundly differs from tight junctions (TJ), analogous structures in animals. Nonetheless, CS membrane domain (CSD) proteins 1-5 (CASP1-5) are homologues of occludins, TJ components. CASP-marked membranes display cell wall (matrix) adhesion and membrane protein exclusion. A full CASP knock-out now reveals CASPs are not needed for localized lignification, since correctly positioned lignin microdomains still form in the mutant. Ultra-structurally, however, these microdomains are disorganized, showing excessive cell wall growth, lack of exclusion zone and matrix adhesion, and impaired exocyst dynamics. Proximity-labelling identifies a Rab-GTPase subfamily, known exocyst activators, as potential CASP-interactors and demonstrate their localization and function at the CSD. We propose that CASP microdomains displace initial secretory foci by excluding vesicle tethering factors, thereby ensuring rapid fusion of microdomains into a membrane-cell wall band that seals the extracellular space.
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Affiliation(s)
- Inês Catarina Ramos Barbosa
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland.
| | - Damien De Bellis
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland
| | - Isabelle Flückiger
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland
| | - Etienne Bellani
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland
| | - Mathieu Grangé-Guerment
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland
| | - Kian Hématy
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland
- Institut Jean-Pierre Bourgin, INRAe, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Niko Geldner
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, 1015, Lausanne, Switzerland.
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12
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Placidi G, Mattu C, Ciardelli G, Campa CC. Small molecules targeting endocytic uptake and recycling pathways. Front Cell Dev Biol 2023; 11:1125801. [PMID: 36968200 PMCID: PMC10036367 DOI: 10.3389/fcell.2023.1125801] [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: 12/16/2022] [Accepted: 02/23/2023] [Indexed: 03/12/2023] Open
Abstract
Over the past years a growing number of studies highlighted the pivotal role of intracellular trafficking in cell physiology. Among the distinct transport itineraries connecting the endocytic system, both internalization (endocytosis) and recycling (endocytic recycling) pathways were found fundamental to ensure cellular sensing, cell-to-cell communication, cellular division, and collective cell migration in tissue specific-contexts. Consistently, the dysregulation of endocytic trafficking pathways is correlated with several human diseases including both cancers and neurodegeneration. Aimed at suppress specific intracellular trafficking routes involved in disease onset and progression, huge efforts have been made to identify small molecule inhibitors with suitable pharmacological properties for in vivo administration. Here, we review most used drugs and recently discovered small molecules able to block endocytosis and endocytic recycling pathways. We characterize such pharmacological inhibitors by emphasizing their target specificity, molecular affinity, biological activity and efficacy in both in vitro and in vivo experimental models.
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Affiliation(s)
- Giampaolo Placidi
- Italian Institute for Genomic Medicine, Candiolo, Italy
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Clara Mattu
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Gianluca Ciardelli
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
- Chemical-Physical Processes, National Research Council (CNR-IPCF), Pisa, Italy
| | - Carlo C. Campa
- Italian Institute for Genomic Medicine, Candiolo, Italy
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Italy
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13
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Ravindran P, Püschel AW. An isoform-specific function of Cdc42 in regulating mammalian Exo70 during axon formation. Life Sci Alliance 2023; 6:6/3/e202201722. [PMID: 36543541 PMCID: PMC9772827 DOI: 10.26508/lsa.202201722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
The highly conserved GTPase Cdc42 is an essential regulator of cell polarity and promotes exocytosis through the exocyst complex in budding yeast and Drosophila In mammals, this function is performed by the closely related GTPase TC10, whereas mammalian Cdc42 does not interact with the exocyst. Axon formation is facilitated by the exocyst complex that tethers vesicles before their fusion to expand the plasma membrane. This function depends on the recruitment of the Exo70 subunit to the plasma membrane. Alternative splicing generates two Cdc42 isoforms that differ in their C-terminal 10 amino acids. Our results identify an isoform-specific function of Cdc42 in neurons. We show that the brain-specific Cdc42b isoform, in contrast to the ubiquitous isoform Cdc42u, can interact with Exo70. Inactivation of Arhgef7 or Cdc42b interferes with the exocytosis of post-Golgi vesicles in the growth cone. Cdc42b regulates exocytosis and axon formation downstream of its activator Arhgef7. Thus, the function of Cdc42 in regulating exocytosis is conserved in mammals but specific to one isoform.
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Affiliation(s)
- Priyadarshini Ravindran
- Institut für Integrative Zellbiologie und Physiologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Andreas W Püschel
- Institut für Integrative Zellbiologie und Physiologie, Westfälische Wilhelms-Universität, Münster, Germany .,Cells-in-Motion Interfaculty Center, University of Münster, Münster, Germany
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14
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Zhao K, Matsunaga K, Mizuno K, Wang H, Okunishi K, Izumi T. Functional hierarchy among different Rab27 effectors involved in secretory granule exocytosis. eLife 2023; 12:82821. [PMID: 36803984 PMCID: PMC9988257 DOI: 10.7554/elife.82821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 02/21/2023] [Indexed: 02/23/2023] Open
Abstract
The Rab27 effectors are known to play versatile roles in regulated exocytosis. In pancreatic beta cells, exophilin-8 anchors granules in the peripheral actin cortex, whereas granuphilin and melanophilin mediate granule fusion with and without stable docking to the plasma membrane, respectively. However, it is unknown whether these coexisting effectors function in parallel or in sequence to support the whole insulin secretory process. Here, we investigate their functional relationships by comparing the exocytic phenotypes in mouse beta cells simultaneously lacking two effectors with those lacking just one of them. Analyses of prefusion profiles by total internal reflection fluorescence microscopy suggest that melanophilin exclusively functions downstream of exophilin-8 to mobilize granules for fusion from the actin network to the plasma membrane after stimulation. The two effectors are physically linked via the exocyst complex. Downregulation of the exocyst component affects granule exocytosis only in the presence of exophilin-8. The exocyst and exophilin-8 also promote fusion of granules residing beneath the plasma membrane prior to stimulation, although they differentially act on freely diffusible granules and those stably docked to the plasma membrane by granuphilin, respectively. This is the first study to diagram the multiple intracellular pathways of granule exocytosis and the functional hierarchy among different Rab27 effectors within the same cell.
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Affiliation(s)
- Kunli Zhao
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma UniversityMaebashiJapan
| | - Kohichi Matsunaga
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma UniversityMaebashiJapan
| | - Kouichi Mizuno
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma UniversityMaebashiJapan
| | - Hao Wang
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma UniversityMaebashiJapan
| | - Katsuhide Okunishi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma UniversityMaebashiJapan
| | - Tetsuro Izumi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma UniversityMaebashiJapan
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15
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GEF-H1 Transduces FcεRI Signaling in Mast Cells to Activate RhoA and Focal Adhesion Formation during Exocytosis. Cells 2023; 12:cells12040537. [PMID: 36831204 PMCID: PMC9954420 DOI: 10.3390/cells12040537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023] Open
Abstract
When antigen-stimulated, mast cells release preformed inflammatory mediators stored in cytoplasmic granules. This occurs via a robust exocytosis mechanism termed degranulation. Our previous studies revealed that RhoA and Rac1 are activated during mast cell antigen stimulation and are required for mediator release. Here, we show that the RhoGEF, GEF-H1, acts as a signal transducer of antigen stimulation to activate RhoA and promote mast cell spreading via focal adhesion (FA) formation. Cell spreading, granule movement, and exocytosis were all reduced in antigen-stimulated mast cells when GEF-H1 was depleted by RNA interference. GEF-H1-depleted cells also showed a significant reduction in RhoA activation, resulting in reduced stress fiber formation without altering lamellipodia formation. Ectopic expression of a constitutively active RhoA mutant restored normal morphology in GEF-H1-depleted cells. FA formation during antigen stimulation required GEF-H1, suggesting it is a downstream target of the GEF-H1-RhoA signaling axis. GEF-H1 was activated by phosphorylation in conjunction with antigen stimulation. Syk kinase is linked to the FcεRI signaling pathway and the Syk inhibitor, GS-9973, blocked GEF-H1 activation and also suppressed cell spreading, granule movement, and exocytosis. We concluded that during FcεRI receptor stimulation, GEF-H1 transmits signals to RhoA activation and FA formation to facilitate the exocytosis mechanism.
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16
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Miller BK, Rossi G, Hudson S, Cully D, Baker RW, Brennwald P. Allosteric regulation of exocyst: Discrete activation of tethering by two spatial signals. J Cell Biol 2023; 222:213852. [PMID: 36729146 PMCID: PMC9929655 DOI: 10.1083/jcb.202206108] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 11/17/2022] [Accepted: 01/05/2023] [Indexed: 02/03/2023] Open
Abstract
The exocyst imparts spatial control during exocytic vesicle tethering through its interactions with proteins and lipids on the vesicle and the plasma membrane. One such interaction is with the vesicle tether Sro7, although the outcome of this interaction is poorly understood. Here, we describe how Sro7 binding to the Exo84 subunit results in activation of the exocyst complex which leads to an increase in avidity for the Rab GTPase Sec4 and an increase in exocyst-mediated vesicle tethering. Gain-of-function (GOF) mutations in Exo84 that mimic Sro7 activation replicate these biochemical changes and result in allosteric changes within the complex. Direct comparison of GOF mutants which mimic Sro7- and Rho/Cdc42-activation of the exocyst reveals distinct mechanisms and outcomes. We propose a model by which these two activation pathways reside within the same tethering complex but remain insulated from one another. Structural modeling suggests a related mechanism for Sro7 activation of the exocyst in yeast and Ral GTPase activation of the exocyst in animal cells.
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Affiliation(s)
- Brittany K. Miller
- https://ror.org/0130frc33Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Guendalina Rossi
- https://ror.org/0130frc33Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Sara Hudson
- https://ror.org/0130frc33Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - David Cully
- https://ror.org/0130frc33Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Richard W. Baker
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Patrick Brennwald
- https://ror.org/0130frc33Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA,Correspondence to Patrick Brennwald:
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17
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Phanprasert Y, Maciszewski K, Gentekaki E, Dacks JB. Comparative genomic analysis illustrates evolutionary dynamics of multisubunit tethering complexes across green algal diversity. J Eukaryot Microbiol 2023; 70:e12935. [PMID: 35790054 DOI: 10.1111/jeu.12935] [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: 05/17/2022] [Revised: 06/21/2022] [Accepted: 06/29/2022] [Indexed: 01/13/2023]
Abstract
The chlorophyte algae are a dominant group of photosynthetic eukaryotes. Although many are photoautotrophs, there are also mixotrophs, heterotrophs, and even parasites. The physical characteristics of green algae are also highly diverse, varying greatly in size, shape, and habitat. Given this morphological and trophic diversity, we postulated that diversity may also exist in the protein components controlling intracellular movement of material by vesicular transport. One such set is the multisubunit tethering complexes (MTCs)-components regulating cargo delivery. As they span endomembrane organelles and are well-conserved across eukaryotes, MTCs should be a good proxy for assessing the evolutionary dynamics across the diversity of Chlorophyta. Our results reveal that while green algae carry a generally conserved and unduplicated complement of MTCs, some intriguing variation exists. Notably, we identified incomplete sets of TRAPPII, exocyst, and HOPS/CORVET components in all Mamiellophyceae, and what is more, not a single subunit of Dsl1 was found in Cymbomonas tetramitiformis. As the absence of Dsl1 has been correlated with having unusual peroxisomes, we searched for peroxisome biogenesis machinery, finding very few components in Cymbomonas, suggestive of peroxisome degeneration. Overall, we demonstrate conservation of MTCs across green algae, but with notable taxon-specific losses suggestive of unusual endomembrane systems.
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Affiliation(s)
| | - Kacper Maciszewski
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Eleni Gentekaki
- School of Science, Mae Fah Luang University, Chiang Rai, Thailand.,Gut Microbiome Research Group, Mae Fah Luang University, Chiang Rai, Thailand
| | - Joel B Dacks
- Division of Infectious Diseases, University of Alberta, Edmonton, Alberta, Canada.,Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Institute of Evolutionary Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
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18
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Listeria monocytogenes Co-Opts the Host Exocyst Complex To Promote Internalin A-Mediated Entry. Infect Immun 2022; 90:e0032622. [PMID: 36255255 PMCID: PMC9753705 DOI: 10.1128/iai.00326-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The bacterial pathogen Listeria monocytogenes induces its internalization (entry) into intestinal epithelial cells through interaction of its surface protein, internalin A (InlA), with the human cell-cell adhesion molecule, E-cadherin. While InlA-mediated entry requires bacterial stimulation of actin polymerization, it remains unknown whether additional host processes are manipulated to promote internalization. Here, we show that interaction of InlA with E-cadherin induces the host membrane-trafficking process of polarized exocytosis, which augments uptake of Listeria. Imaging studies revealed that exocytosis is stimulated at sites of InlA-dependent internalization. Experiments inhibiting human N-ethylmaleimide-sensitive factor (NSF) demonstrated that exocytosis is needed for efficient InlA-mediated entry. Polarized exocytosis is mediated by the exocyst complex, which comprises eight proteins, including Sec6, Exo70, and Exo84. We found that Exo70 was recruited to sites of InlA-mediated entry. In addition, depletion of Exo70, Exo84, or Sec6 by RNA interference impaired entry without affecting surface levels of E-cadherin. Similar to binding of InlA to E-cadherin, homophilic interaction of E-cadherin molecules mobilized the exocyst and stimulated exocytosis. Collectively, these results demonstrate that ligation of E-cadherin induces exocytosis that promotes Listeria entry, and they raise the possibility that the exocyst might also control the normal function of E-cadherin in cell-cell adhesion.
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19
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Behrens LM, van Egmond M, van den Berg TK. Neutrophils as immune effector cells in antibody therapy in cancer. Immunol Rev 2022; 314:280-301. [PMID: 36331258 DOI: 10.1111/imr.13159] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tumor-targeting monoclonal antibodies are available for a number of cancer cell types (over)expressing the corresponding tumor antigens. Such antibodies can limit tumor progression by different mechanisms, including direct growth inhibition and immune-mediated mechanisms, in particular complement-dependent cytotoxicity, antibody-dependent cellular phagocytosis, and antibody-dependent cellular cytotoxicity (ADCC). ADCC can be mediated by various types of immune cells, including neutrophils, the most abundant leukocyte in circulation. Neutrophils express a number of Fc receptors, including Fcγ- and Fcα-receptors, and can therefore kill tumor cells opsonized with either IgG or IgA antibodies. In recent years, important insights have been obtained with respect to the mechanism(s) by which neutrophils engage and kill antibody-opsonized cancer cells and these findings are reviewed here. In addition, we consider a number of additional ways in which neutrophils may affect cancer progression, in particular by regulating adaptive anti-cancer immunity.
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Affiliation(s)
- Leonie M. Behrens
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC Vrije Universiteit Amsterdam HV Amsterdam The Netherlands
- Cancer Center Amsterdam, Cancer Biology and Immunology HV Amsterdam The Netherlands
- Amsterdam institute for Infection and Immunity, Cancer Immunology HV Amsterdam The Netherlands
| | - Marjolein van Egmond
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC Vrije Universiteit Amsterdam HV Amsterdam The Netherlands
- Cancer Center Amsterdam, Cancer Biology and Immunology HV Amsterdam The Netherlands
- Amsterdam institute for Infection and Immunity, Cancer Immunology HV Amsterdam The Netherlands
- Department of Surgery, Amsterdam UMC Vrije Universiteit Amsterdam HV Amsterdam The Netherlands
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20
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Gingras RM, Sulpizio AM, Park J, Bretscher A. High-resolution secretory timeline from vesicle formation at the Golgi to fusion at the plasma membrane in S. cerevisiae. eLife 2022; 11:e78750. [PMID: 36331188 PMCID: PMC9671497 DOI: 10.7554/elife.78750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022] Open
Abstract
Most of the components in the yeast secretory pathway have been studied, yet a high-resolution temporal timeline of their participation is lacking. Here, we define the order of acquisition, lifetime, and release of critical components involved in late secretion from the Golgi to the plasma membrane. Of particular interest is the timing of the many reported effectors of the secretory vesicle Rab protein Sec4, including the myosin-V Myo2, the exocyst complex, the lgl homolog Sro7, and the small yeast-specific protein Mso1. At the trans-Golgi network (TGN) Sec4's GEF, Sec2, is recruited to Ypt31-positive compartments, quickly followed by Sec4 and Myo2 and vesicle formation. While transported to the bud tip, the entire exocyst complex, including Sec3, is assembled on to the vesicle. Before fusion, vesicles tether for 5 s, during which the vesicle retains the exocyst complex and stimulates lateral recruitment of Rho3 on the plasma membrane. Sec2 and Myo2 are rapidly lost, followed by recruitment of cytosolic Sro7, and finally the SM protein Sec1, which appears for just 2 s prior to fusion. Perturbation experiments reveal an ordered and robust series of events during tethering that provide insights into the function of Sec4 and effector exchange.
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Affiliation(s)
- Robert M Gingras
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Abigail M Sulpizio
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Joelle Park
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Anthony Bretscher
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
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21
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Feng MW, Delneri D, Millar CB, O'Keefe RT. Eisosome disruption by noncoding RNA deletion increases protein secretion in yeast. PNAS NEXUS 2022; 1:pgac241. [PMID: 36712349 PMCID: PMC9802208 DOI: 10.1093/pnasnexus/pgac241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/24/2022] [Indexed: 11/07/2022]
Abstract
Noncoding RNAs (ncRNAs) regulate many aspects of gene expression. We investigated how ncRNAs affected protein secretion in yeast by large-scale screening for improved endogenous invertase secretion in ncRNA deletion strains with deletion of stable unannotated transcripts (SUTs), cryptic unstable transcripts (CUTs), tRNAs, or snRNAs. We identified three candidate ncRNAs, SUT418, SUT390, and SUT125, that improved endogenous invertase secretion when deleted. As SUTs can affect expression of nearby genes, we quantified adjacent gene transcription and found that the PIL1 gene was down-regulated in the SUT125 deletion strain. Pil1 is a core component of eisosomes, nonmobile invaginations found throughout the plasma membrane. PIL1 knockout alone, or in combination with eisosome components LSP1 or SUR7, resulted in further increased secretion of invertase. Secretion of heterologous GFP was also increased upon PIL1 deletion, but this increase was signal sequence dependent. To reveal the potential for increased biopharmaceutical production, secretion of monoclonal antibody Pexelizumab scFv peptide was increased by PIL1 deletion. Global analysis of secreted proteins revealed that approximately 20% of secreted proteins, especially serine-enriched secreted proteins, including invertase, were increased upon eisosome disruption. Eisosomes are enriched with APC transporters and sphingolipids, which are essential components for secretory vesicle formation and protein sorting. Sphingolipid and serine biosynthesis pathways were up-regulated upon PIL1 deletion. We propose that increased secretion of endogenous and heterologous proteins upon PIL1 deletion resulted from sphingolipid redistribution in the plasma membrane and up-regulated sphingolipid biosynthesis. Overall, a new pathway to improve protein secretion in yeast via eisosome disruption has been identified.
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Affiliation(s)
- Matthew Wenjie Feng
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Daniela Delneri
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK,Manchester Institute of Biotechnology, Faculty of Biology Medicine and Health, The University of Manchester, 131 Princess street, Manchester, M1 7DN, UK
| | - Catherine B Millar
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
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22
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De la Concepcion JC, Fujisaki K, Bentham AR, Cruz Mireles N, Sanchez de Medina Hernandez V, Shimizu M, Lawson DM, Kamoun S, Terauchi R, Banfield MJ. A blast fungus zinc-finger fold effector binds to a hydrophobic pocket in host Exo70 proteins to modulate immune recognition in rice. Proc Natl Acad Sci U S A 2022; 119:e2210559119. [PMID: 36252011 PMCID: PMC9618136 DOI: 10.1073/pnas.2210559119] [Citation(s) in RCA: 10] [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] [Indexed: 11/18/2022] Open
Abstract
Exocytosis plays an important role in plant-microbe interactions, in both pathogenesis and symbiosis. Exo70 proteins are integral components of the exocyst, an octameric complex that mediates tethering of vesicles to membranes in eukaryotes. Although plant Exo70s are known to be targeted by pathogen effectors, the underpinning molecular mechanisms and the impact of this interaction on infection are poorly understood. Here, we show the molecular basis of the association between the effector AVR-Pii of the blast fungus Maganaporthe oryzae and rice Exo70 alleles OsExo70F2 and OsExo70F3, which is sensed by the immune receptor pair Pii via an integrated RIN4/NOI domain. The crystal structure of AVR-Pii in complex with OsExo70F2 reveals that the effector binds to a conserved hydrophobic pocket in Exo70, defining an effector/target binding interface. Structure-guided and random mutagenesis validates the importance of AVR-Pii residues at the Exo70 binding interface to sustain protein association and disease resistance in rice when challenged with fungal strains expressing effector mutants. Furthermore, the structure of AVR-Pii defines a zinc-finger effector fold (ZiF) distinct from the MAX (Magnaporthe Avrs and ToxB-like) fold previously described for a majority of characterized M. oryzae effectors. Our data suggest that blast fungus ZiF effectors bind a conserved Exo70 interface to manipulate plant exocytosis and that these effectors are also baited by plant immune receptors, pointing to new opportunities for engineering disease resistance.
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Affiliation(s)
| | - Koki Fujisaki
- bDivision of Genomics and Breeding, Iwate Biotechnology Research Center, Iwate, 024-0003, Japan
| | - Adam R. Bentham
- aDepartment of Biochemistry and Metabolism, John Innes Centre, Norwich, NR4 7UH, United Kingdom
| | - Neftaly Cruz Mireles
- aDepartment of Biochemistry and Metabolism, John Innes Centre, Norwich, NR4 7UH, United Kingdom
- cThe Sainsbury Laboratory, University of East Anglia, Norwich, NR4 7UH, United Kingdom
| | | | - Motoki Shimizu
- bDivision of Genomics and Breeding, Iwate Biotechnology Research Center, Iwate, 024-0003, Japan
| | - David M. Lawson
- aDepartment of Biochemistry and Metabolism, John Innes Centre, Norwich, NR4 7UH, United Kingdom
| | - Sophien Kamoun
- cThe Sainsbury Laboratory, University of East Anglia, Norwich, NR4 7UH, United Kingdom
| | - Ryohei Terauchi
- bDivision of Genomics and Breeding, Iwate Biotechnology Research Center, Iwate, 024-0003, Japan
- dLaboratory of Crop Evolution, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8501, Japan
| | - Mark J. Banfield
- aDepartment of Biochemistry and Metabolism, John Innes Centre, Norwich, NR4 7UH, United Kingdom
- 2To whom correspondence may be addressed.
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23
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Ortega MA, Villiger RK, Harrison-Chau M, Lieu S, Tamashiro KK, Lee AJ, Fujimoto BA, Patwardhan GY, Kepler J, Fogelgren B. Exocyst inactivation in urothelial cells disrupts autophagy and activates non-canonical NF-κB signaling. Dis Model Mech 2022; 15:dmm049785. [PMID: 36004645 PMCID: PMC9586569 DOI: 10.1242/dmm.049785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 07/28/2022] [Indexed: 12/02/2022] Open
Abstract
Ureter obstruction is a highly prevalent event during embryonic development and is a major cause of pediatric kidney disease. We have previously reported that ureteric bud-specific ablation of the gene expressing the exocyst subunit EXOC5 in late murine gestation results in failure of urothelial stratification, cell death and complete ureter obstruction. However, the mechanistic connection between disrupted exocyst activity, urothelial cell death and subsequent ureter obstruction was unclear. Here, we report that inhibited urothelial stratification does not drive cell death during ureter development. Instead, we demonstrate that the exocyst plays a critical role in autophagy in urothelial cells, and that disruption of autophagy activates a urothelial NF-κB stress response. Impaired autophagy first provokes canonical NF-κB activity, which is progressively followed by increasing levels of non-canonical NF-κB activity and cell death if the stress remains unresolved. Furthermore, we demonstrate that ureter obstructions can be completely rescued in Exoc5 conditional knockout mice by administering a single dose of the pan-caspase inhibitor z-VAD-FMK at embryonic day 16.5 prior to urothelial cell death. Taken together, ablation of Exoc5 disrupts autophagic stress response and activates progressive NF-κB signaling, which promotes obstructive uropathy.
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Affiliation(s)
- Michael A. Ortega
- Center for Biomedical Research at The Queen's Medical Center, Honolulu, Hawaii 96813, USA
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Ross K. Villiger
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Malia Harrison-Chau
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Suzanna Lieu
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Kadee-Kalia Tamashiro
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Amanda J. Lee
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
- Math and Sciences Department, Kapiolani Community College, Honolulu, Hawaii 96816, USA
| | - Brent A. Fujimoto
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Geetika Y. Patwardhan
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Joshua Kepler
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
| | - Ben Fogelgren
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaiʿi at Manoa, Honolulu, Hawaii 96813, USA
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24
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Zhang AS, Enns CA. Grab and go: transferrin uptake in erythropoiesis. Blood 2022; 140:1061-1063. [PMID: 36074530 DOI: 10.1182/blood.2022017638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/21/2022] [Indexed: 11/20/2022] Open
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25
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Michalopoulou VA, Mermigka G, Kotsaridis K, Mentzelopoulou A, Celie PHN, Moschou PN, Jones JDG, Sarris PF. The host exocyst complex is targeted by a conserved bacterial type-III effector that promotes virulence. THE PLANT CELL 2022; 34:3400-3424. [PMID: 35640532 PMCID: PMC9421483 DOI: 10.1093/plcell/koac162] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 05/23/2022] [Indexed: 05/30/2023]
Abstract
For most Gram-negative bacteria, pathogenicity largely depends on the type-III secretion system that delivers virulence effectors into eukaryotic host cells. The subcellular targets for the majority of these effectors remain unknown. Xanthomonas campestris, the causal agent of black rot disease of crucifers such as Brassica spp., radish, and turnip, delivers XopP, a highly conserved core-effector protein produced by X. campestris, which is essential for virulence. Here, we show that XopP inhibits the function of the host-plant exocyst complex by direct targeting of Exo70B, a subunit of the exocyst complex, which plays a significant role in plant immunity. XopP interferes with exocyst-dependent exocytosis and can do this without activating a plant NOD-like receptor that guards Exo70B in Arabidopsis. In this way, Xanthomonas efficiently inhibits the host's pathogen-associated molecular pattern (PAMP)-triggered immunity by blocking exocytosis of pathogenesis-related protein-1A, callose deposition, and localization of the FLAGELLIN SENSITIVE2 (FLS2) immune receptor to the plasma membrane, thus promoting successful infection. Inhibition of exocyst function without activating the related defenses represents an effective virulence strategy, indicating the ability of pathogens to adapt to host defenses by avoiding host immunity responses.
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Affiliation(s)
- Vassiliki A Michalopoulou
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | - Glykeria Mermigka
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | - Konstantinos Kotsaridis
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | | | - Patrick H N Celie
- Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Panagiotis N Moschou
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
- Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnean Center for Plant Biology, Uppsala S-75007, Sweden
| | | | - Panagiotis F Sarris
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
- Biosciences, University of Exeter, Exeter, UK
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26
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Nakamura NK, Tokunaga DS, Ha HY, Polgar N. The Exocyst Is Required for CD36 Fatty Acid Translocase Trafficking and Free Fatty Acid Uptake in Skeletal Muscle Cells. Cells 2022; 11:2440. [PMID: 35954283 PMCID: PMC9368548 DOI: 10.3390/cells11152440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/31/2022] [Accepted: 08/03/2022] [Indexed: 11/26/2022] Open
Abstract
In obesity, chronic membrane-localization of CD36 free fatty acid (FFA) translocase, but not other FFA transporters, enhances FFA uptake and intracellular lipid accumulation. This ectopic lipid accumulation promotes insulin resistance by inhibiting insulin-induced GLUT4 glucose transporter trafficking and glucose uptake. GLUT4 and CD36 cell surface delivery is triggered by insulin- and contraction-induced signaling, which share conserved downstream effectors. While we have gathered detailed knowledge on GLUT4 trafficking, the mechanisms regulating CD36 membrane delivery and subsequent FFA uptake in skeletal muscle are not fully understood. The exocyst trafficking complex facilitates the docking of membrane-bound vesicles, a process underlying the controlled surface delivery of fuel transporters. The exocyst regulates insulin-induced glucose uptake via GLUT4 membrane trafficking in adipocytes and skeletal muscle cells and plays a role in lipid uptake in adipocytes. Based on the high degree of conservation of the GLUT4 and CD36 trafficking mechanisms in adipose and skeletal muscle tissue, we hypothesized that the exocyst also contributes to lipid uptake in skeletal muscle and acts through the targeted plasma membrane delivery of CD36 in response to insulin and contraction. Here, we show that the exocyst complex is necessary for insulin- and contraction-induced CD36 membrane trafficking and FFA uptake in muscle cells.
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Affiliation(s)
| | | | | | - Noemi Polgar
- Department of Anatomy, Biochemistry, and Physiology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA
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27
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Langemeyer L, Ungermann C. Vesicle transport: Exocyst follows PIP 2 to tether membranes. Curr Biol 2022; 32:R748-R750. [PMID: 35820387 DOI: 10.1016/j.cub.2022.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A new study uses reconstituted, functional octameric exocyst complex to provide new insights into the assembly of this tethering complex and reveal how the activity of the lipid kinase PIP5K1C stimulated by Arf6 on exocytic vesicles allows for exocyst-mediated tethering at the plasma membrane.
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Affiliation(s)
- Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section and Center for Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, Barbarastrasse 13, 49076 Osnabrück, Germany.
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section and Center for Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, Barbarastrasse 13, 49076 Osnabrück, Germany.
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28
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Li H, Fu X, Zhao J, Li C, Li L, Xia P, Guo J, Wei W, Zeng R, Wu J, Sun Y, Huang L, Wang X. EXOC4 Promotes Diffuse-Type Gastric Cancer Metastasis via Activating FAK Signal. Mol Cancer Res 2022; 20:1021-1034. [PMID: 35471457 PMCID: PMC9381130 DOI: 10.1158/1541-7786.mcr-21-0441] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/01/2021] [Accepted: 03/17/2022] [Indexed: 01/07/2023]
Abstract
In comparison with intestinal-type gastric cancer, diffuse-type gastric cancer (DGC) is more likely to recur, metastasize, and exhibit worse clinical outcomes; however, the underlying mechanism of DGC recurrence remains elusive. By employing an LC/MS-MS proteomic approach, we identified that exocyst complex component 4 (EXOC4) was significantly upregulated in DGC with recurrence, compared to those with nonrecurrence. High expression of EXOC4 was correlated with tumor metastasis and poor prognosis in patients with DGC. Moreover, EXOC4 promoted cell migration and invasion as well as the tumor metastasis of DGC cells. Mechanistically, EXOC4 regulated the phosphorylation of focal adhesion kinase (FAK) at Y397 sites by stimulating the secretion of integrin α5/β1/EGF and enhancing the interaction of FAK and integrin or EGFR. The FAK inhibitor VS-4718 reversed the metastasis mediated by EXOC4 overexpression and suppressed the tumor growth of patient-derived xenografts derived from DGC with high EXOC4 expression. The EXOC4-FAK axis could be a potential therapeutic target for patients with DGC with high expression of EXOC4. IMPLICATIONS The EXOC4-FAK axis promoted DGC metastasis and could be a potential therapeutic target for patients with DGC.
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Affiliation(s)
- Haojie Li
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China
| | - Xuhong Fu
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Junjie Zhao
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China
| | - Chen Li
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lingmeng Li
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Peiyan Xia
- University of Michigan-Shanghai Jiaotong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Jianping Guo
- Institute of Precision Medicine, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Rong Zeng
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jiarui Wu
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Yihong Sun
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Liyu Huang
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Xuefei Wang
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
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29
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Žárský V. Exocyst functions in plants - secretion and autophagy. FEBS Lett 2022; 596:2324-2334. [PMID: 35729750 DOI: 10.1002/1873-3468.14430] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/03/2022] [Accepted: 06/03/2022] [Indexed: 11/09/2022]
Abstract
Tethering complexes mediate vesicle-target compartment contact. Octameric complex exocyst initiates vesicle exocytosis at specific cytoplasmic membrane domains. Plant exocyst is possibly stabilized at the membrane by a direct interaction between SEC3 and EXO70A. Land plants evolved three basic membrane-targeting EXO70 subfamilies, the evolution of which resulted in several types of exocyst with distinct functions within the same cell. Surprisingly, some of these EXO70-exocyst versions are implicated in autophagy as is animal exocyst or are involved in host defense, cell-wall fortification and secondary metabolites transport. Interestingly, EXO70Ds act as selective autophagy receptors in the regulation of cytokinin signalling pathway. Secretion of double membrane autophagy-related structures formed with the contribution of EXO70s to the apoplast hints at the possibility of secretory autophagy in plants.
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Affiliation(s)
- Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, 128 44, Prague, Czech Republic.,Institute of Experimental Botany, v.v.i., Czech Academy of Sciences, Rozvojová 263, 165 02, Prague, Czech Republic
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30
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van Rees DJ, Bouti P, Klein B, Verkuijlen PJH, van Houdt M, Schornagel K, Tool ATJ, Venet D, Sotiriou C, El-Abed S, Izquierdo M, Guillaume S, Saura C, Di Cosimo S, Huober J, Roylance R, Kim SB, Kuijpers TW, van Bruggen R, van den Berg TK, Matlung HL. Cancer cells resist antibody-mediated destruction by neutrophils through activation of the exocyst complex. J Immunother Cancer 2022; 10:e004820. [PMID: 35728876 PMCID: PMC9214435 DOI: 10.1136/jitc-2022-004820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2022] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Neutrophils kill antibody-opsonized tumor cells using trogocytosis, a unique mechanism of destruction of the target plasma. This previously unknown cytotoxic process of neutrophils is dependent on antibody opsonization, Fcγ receptors and CD11b/CD18 integrins. Here, we demonstrate that tumor cells can escape neutrophil-mediated cytotoxicity by calcium (Ca2+)-dependent and exocyst complex-dependent plasma membrane repair. METHODS We knocked down EXOC7 or EXOC4, two exocyst components, to evaluate their involvement in tumor cell membrane repair after neutrophil-induced trogocytosis. We used live cell microscopy and flow cytometry for visualization of the host and tumor cell interaction and tumor cell membrane repair. Last, we reported the mRNA levels of exocyst in breast cancer tumors in correlation to the response in trastuzumab-treated patients. RESULTS We found that tumor cells can evade neutrophil antibody-dependent cellular cytotoxicity (ADCC) by Ca2+-dependent cell membrane repair, a process induced upon neutrophil trogocytosis. Absence of exocyst components EXOC7 or EXOC4 rendered tumor cells vulnerable to neutrophil-mediated ADCC (but not natural killer cell-mediated killing), while neutrophil trogocytosis remained unaltered. Finally, mRNA levels of exocyst components in trastuzumab-treated patients were inversely correlated to complete response to therapy. CONCLUSIONS Our results support that neutrophil attack towards antibody-opsonized cancer cells by trogocytosis induces an active repair process by the exocyst complex in vitro. Our findings provide insight to the possible contribution of neutrophils in current antibody therapies and the tolerance mechanism of tumor cells and support further studies for potential use of the exocyst components as clinical biomarkers.
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Affiliation(s)
- Dieke J van Rees
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Panagiota Bouti
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Bart Klein
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Paul J H Verkuijlen
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Michel van Houdt
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Karin Schornagel
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Anton T J Tool
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - David Venet
- Breast Cancer Translational Research Laboratory JC Heuson, Institut Jules Bordet, Bruxelles, Belgium
| | - Christos Sotiriou
- Breast Cancer Translational Research Laboratory JC Heuson, Institut Jules Bordet, Bruxelles, Belgium
| | | | | | - Sébastien Guillaume
- Department of Psychiatric Emergency & Acute Care, Lapeyronie Hospital, Montpellier, France
| | - Cristina Saura
- SOLTI Innovative Breast Cancer Research, Vall d'Hebron Hospital Universitari, Barcelona, Spain
| | | | - Jens Huober
- Breast Center, University of Ulm, Ulm, Germany
| | - Rebecca Roylance
- Department of Oncology, University College London Hospitals NHS Foundation Trust and NIHR University College London Hospitals Biomedical Research Centre, London, UK
| | - Sung-Bae Kim
- Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Taco W Kuijpers
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
- Department of Pediatric Immunology and Infectious Diseases, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Robin van Bruggen
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Timo K van den Berg
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Hanke L Matlung
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
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31
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Tanasic D, Berns N, Riechmann V. Myosin V facilitates polarised E-cadherin secretion. Traffic 2022; 23:374-390. [PMID: 35575181 DOI: 10.1111/tra.12846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/09/2022] [Accepted: 05/09/2022] [Indexed: 11/30/2022]
Abstract
E-cadherin has a fundamental role in epithelial tissues by providing cell-cell adhesion. Polarised E-cadherin exocytosis to the lateral plasma membrane is central for cell polarity and epithelial homeostasis. Loss of E-cadherin secretion compromises tissue integrity and is a prerequisite for metastasis. Despite this pivotal role of E-cadherin secretion, the transport mechanism is still unknown. Here we identify Myosin V as the motor for E-cadherin secretion. Our data reveal that Myosin V and F-actin are required for the formation of a continuous apicolateral E-cadherin belt, the zonula adherens. We show by live imaging how Myosin V transports E-cadherin vesicles to the plasma membrane, and distinguish two distinct transport tracks: an apical actin network leading to the zonula adherens and parallel actin bundles leading to the basal-most region of the lateral membrane. E-cadherin secretion starts in endosomes, where Rab11 and Sec15 recruit Myosin V for transport to the zonula adherens. We also shed light on the endosomal sorting of E-cadherin by showing how Rab7 and Snx16 cooperate in moving E-cadherin into the Rab11 compartment. Thus, our data help to understand how polarised E-cadherin secretion maintains epithelial architecture and prevents metastasis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Dajana Tanasic
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, Mannheim, Germany
| | - Nicola Berns
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, Mannheim, Germany
| | - Veit Riechmann
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, Mannheim, Germany
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A mechanism for exocyst-mediated tethering via Arf6 and PIP5K1C-driven phosphoinositide conversion. Curr Biol 2022; 32:2821-2833.e6. [PMID: 35609603 PMCID: PMC9382030 DOI: 10.1016/j.cub.2022.04.089] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 03/08/2022] [Accepted: 04/28/2022] [Indexed: 11/22/2022]
Abstract
Polarized trafficking is necessary for the development of eukaryotes and is regulated by a conserved molecular machinery. Late steps of cargo delivery are mediated by the exocyst complex, which integrates lipid and protein components to tether vesicles for plasma membrane fusion. However, the molecular mechanisms of this process are poorly defined. Here, we reconstitute functional octameric human exocyst, demonstrating the basis for holocomplex coalescence and biochemically stable subcomplexes. We determine that each subcomplex independently binds to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), which is minimally sufficient for membrane tethering. Through reconstitution and epithelial cell biology experiments, we show that Arf6-mediated recruitment of the lipid kinase PIP5K1C rapidly converts phosphatidylinositol 4-phosphate (PI(4)P) to PI(4,5)P2, driving exocyst recruitment and membrane tethering. These results provide a molecular mechanism of exocyst-mediated tethering and a unique functional requirement for phosphoinositide signaling on late-stage vesicles in the vicinity of the plasma membrane. Complete reconstitution and subunit connectivity of the human exocyst complex Binding to PI(4,5)P2 in trans by each subcomplex enables membrane tethering PI(4)P to PI(4,5)P2 conversion is sufficient for exocyst recruitment and tethering Arf6 controls phosphoinositide conversion by PIP5K1C in cells and in vitro
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Rab33b-exocyst interaction mediates localized secretion for focal adhesion turnover and cell migration. iScience 2022; 25:104250. [PMID: 35521520 PMCID: PMC9061791 DOI: 10.1016/j.isci.2022.104250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 02/17/2022] [Accepted: 04/08/2022] [Indexed: 12/19/2022] Open
Abstract
Rab proteins are well known regulators of intracellular trafficking; however, more and more studies point to their function also in other cellular processes, including cell migration. In this work, we have performed an siRNA screen to identify Rab proteins that influence cell migration. The screen revealed Rab33b as the strongest candidate that affected cell motility. Rab33b has been previously reported to localize at the Golgi apparatus to regulate Golgi-to-ER retrograde trafficking and Golgi homeostasis. We revealed that Rab33b also mediates post-Golgi transport to the plasma membrane. We further identified Exoc6, a subunit of the exocyst complex, as an interactor of Rab33b. Moreover, our data indicate that Rab33b regulates focal adhesion dynamics by modulating the delivery of cargo such as integrins to focal adhesions. Altogether, our results demonstrate a role for Rab33b in cell migration by regulating the delivery of integrins to focal adhesions through the interaction with Exoc6. RNAi screen reveals a role for Rab33b in cell migration Rab33b influences focal adhesion dynamics Rab33b interacts with the exocyst subunit Exoc6 Rab33b together with Exoc6 mediates the delivery of β1 integrin to adhesion points
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Distinct mechanisms orchestrate the contra-polarity of IRK and KOIN, two LRR-receptor-kinases controlling root cell division. Nat Commun 2022; 13:235. [PMID: 35017541 PMCID: PMC8752632 DOI: 10.1038/s41467-021-27913-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 12/22/2021] [Indexed: 11/24/2022] Open
Abstract
In plants, cell polarity plays key roles in coordinating developmental processes. Despite the characterization of several polarly localized plasma membrane proteins, the mechanisms connecting protein dynamics with cellular functions often remain unclear. Here, we introduce a polarized receptor, KOIN, that restricts cell divisions in the Arabidopsis root meristem. In the endodermis, KOIN polarity is opposite to IRK, a receptor that represses endodermal cell divisions. Their contra-polar localization facilitates dissection of polarity mechanisms and the links between polarity and function. We find that IRK and KOIN are recognized, sorted, and secreted through distinct pathways. IRK extracellular domains determine its polarity and partially rescue the mutant phenotype, whereas KOIN’s extracellular domains are insufficient for polar sorting and function. Endodermal expression of an IRK/KOIN chimera generates non-cell-autonomous misregulation of root cell divisions that impacts patterning. Altogether, we reveal two contrasting mechanisms determining these receptors’ polarity and link their polarity to cell divisions in root tissue patterning. Protein polarization coordinates many plant developmental processes. Here the authors show that IRK and KOIN, two LRR-receptor-kinases polarized to opposite sides of cells in the root meristem, rely on distinct mechanisms to achieve polarity.
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Ahmed SM. Generation of Endogenously Tagged Membrane Trafficking Regulators Using CRISPR Genome Editing. Methods Mol Biol 2022; 2473:47-63. [PMID: 35819758 DOI: 10.1007/978-1-0716-2209-4_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Vesicle trafficking entails packaging and transport of membrane-associated proteins to their target membranes, and recycling or degradation of endocytosed proteins. Biochemical and cell biological studies of vesicle trafficking often require the introduction of epitope tags or fluorescent protein markers for protein purification and tracking in cells. Previously, such tagging experiments in mammalian cells mainly used overexpression systems, which could lead to artifacts. Abnormally high expression levels also prevent us from studying individual vesicle trafficking events with precision. With the advent of CRISPR technologies, epitope tags and fluorescent proteins can now be introduced into endogenous proteins in almost any cell type that are proliferating in culture. This chapter describes approaches for inserting tags at the endogenous loci of genes, with the vesicle tethering protein complex, exocyst, as an example.
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Affiliation(s)
- Syed Mukhtar Ahmed
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.
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36
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Bustos Plonka F, Sosa LJ, Quiroga S. Sec3 exocyst component knockdown inhibits axonal formation and cortical neuronal migration during brain cortex development. J Neurochem 2021; 160:203-217. [PMID: 34862972 DOI: 10.1111/jnc.15554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 10/27/2021] [Accepted: 11/25/2021] [Indexed: 12/22/2022]
Abstract
Neurons are the largest known cells, with complex and highly polarized morphologies and consist of a cell body (soma), several dendrites, and a single axon. The establishment of polarity necessitates initial axonal outgrowth in concomitance with the addition of new membrane to the axon's plasmalemma. Axolemmal expansion occurs by exocytosis of plasmalemmal precursor vesicles primarily at the neuronal growth cone membrane. The multiprotein exocyst complex drives spatial location and specificity of vesicle fusion at plasma membrane. However, the specific participation of its different proteins on neuronal differentiation has not been fully established. In the present work we analyzed the role of Sec3, a prominent exocyst complex protein on neuronal differentiation. Using mice hippocampal primary cultures, we determined that Sec3 is expressed in neurons at early stages prior to neuronal polarization. Furthermore, we determined that silencing of Sec3 in mice hippocampal neurons in culture precluded polarization. Moreover, using in utero electroporation experiments, we determined that Sec3 knockdown affected cortical neurons migration and morphology during neocortex formation. Our results demonstrate that the exocyst complex protein Sec3 plays an important role in axon formation in neuronal differentiation and the migration of neuronal progenitors during cortex development.
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Affiliation(s)
- Florentyna Bustos Plonka
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba y CIQUIBIC-CONICET, Córdoba, Argentina
| | - Lucas J Sosa
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba y CIQUIBIC-CONICET, Córdoba, Argentina
| | - Santiago Quiroga
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba y CIQUIBIC-CONICET, Córdoba, Argentina
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Wernet N, Wernet V, Fischer R. The small-secreted cysteine-rich protein CyrA is a virulence factor participating in the attack of Caenorhabditis elegans by Duddingtonia flagrans. PLoS Pathog 2021; 17:e1010028. [PMID: 34735554 PMCID: PMC8568293 DOI: 10.1371/journal.ppat.1010028] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/11/2021] [Indexed: 01/14/2023] Open
Abstract
Nematode-trapping fungi (NTF) are a diverse and intriguing group of fungi that live saprotrophically but can switch to a predatory lifestyle when starving and in the presence of nematodes. NTF like Arthrobotrys oligospora or Duddingtonia flagrans produce adhesive trapping networks to catch and immobilize nematodes. After penetration of the cuticle, hyphae grow and develop inside the worm and secrete large amounts of hydrolytic enzymes for digestion. In many microbial pathogenic interactions small-secreted proteins (SSPs) are used to manipulate the host. The genome of D. flagrans encodes more than 100 of such putative SSPs one of which is the cysteine-rich protein CyrA. We have chosen this gene for further analysis because it is only found in NTF and appeared to be upregulated during the interaction. We show that the cyrA gene was transcriptionally induced in trap cells, and the protein accumulated at the inner rim of the hyphal ring before Caenorhabditis elegans capture. After worm penetration, the protein appeared at the fungal infection bulb, where it is likely to be secreted with the help of the exocyst complex. A cyrA-deletion strain was less virulent, and the time from worm capture to paralysis was extended. Heterologous expression of CyrA in C. elegans reduced its lifespan. CyrA accumulated in C. elegans in coelomocytes where the protein possibly is inactivated. This is the first example that SSPs may be important in predatory microbial interactions.
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Affiliation(s)
- Nicole Wernet
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
| | - Valentin Wernet
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
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38
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Rivera-Molina FE, Xi Z, Reales E, Wang B, Toomre D. Exocyst complex mediates recycling of internal cilia. Curr Biol 2021; 31:5580-5589.e5. [PMID: 34678163 DOI: 10.1016/j.cub.2021.09.067] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 07/22/2021] [Accepted: 09/23/2021] [Indexed: 12/23/2022]
Abstract
Primary cilia are slender, cellular antennae that sense extracellular stimuli, and their absence or dysfunction plays a role in numerous human diseases. Prior work has indicated a role of the exocyst tethering complex in cilia biogenesis and maintenance,1-6 with the underlying paradigm that the exocyst targets vesicles to the ciliary base to deliver ciliary cargoes.7-9 However, the role of the exocyst vis-à-vis to primary cilia in living cells and during stimulation is unknown. Herein, using advanced imaging and quantitative analysis reveals that serum stimulation increases the exocyst's localization to cilia by three-fold. This serum-stimulated localization is highly dynamic, and FRAP experiments show that exocysts at the cilia are highly mobile (60%-80%). Super resolution imaging reveals that the xocyst extends past the cilia base to the entire ciliary pocket. To visualize cilia exocytosis, we conducted live cell imaging with pH-sensitive cilia reporters in combination with extracellular pH switching. Strikingly, we observed that an exocyst-positive internal cilia fuses with the cell surface. These live cell results support a novel and dynamic role of the exocyst complex in the delivery of internalized cilia to the cell surface. Moreover, they suggest a novel pathway may be used to recycle primary cilia to the cell surface that engages the exocyst in response to stimuli. This new remarkable plasticity in cilia presence on the surface in response to extracellular stimuli suggest new means to potentially modulate cilia signaling.
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Affiliation(s)
- Félix E Rivera-Molina
- Department of Cell Biology, School of Medicine, Yale University, 333 Cedar St., New Haven, CT 06520, USA.
| | - Zhiqun Xi
- Department of Cell Biology, School of Medicine, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Elena Reales
- Department of Regeneration and Cell Therapy, Andalusian Molecular Biology and Regenerative Medicine Centre (CABIMER), Seville, Spain
| | - Bryan Wang
- Department of Cell Biology, School of Medicine, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Derek Toomre
- Department of Cell Biology, School of Medicine, Yale University, 333 Cedar St., New Haven, CT 06520, USA.
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Chan EHY, Zhou Y, Aerne BL, Holder MV, Weston A, Barry DJ, Collinson L, Tapon N. RASSF8-mediated transport of Echinoid via the exocyst promotes Drosophila wing elongation and epithelial ordering. Development 2021; 148:dev199731. [PMID: 34532737 PMCID: PMC8572004 DOI: 10.1242/dev.199731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/13/2021] [Indexed: 01/14/2023]
Abstract
Cell-cell junctions are dynamic structures that maintain cell cohesion and shape in epithelial tissues. During development, junctions undergo extensive rearrangements to drive the epithelial remodelling required for morphogenesis. This is particularly evident during axis elongation, where neighbour exchanges, cell-cell rearrangements and oriented cell divisions lead to large-scale alterations in tissue shape. Polarised vesicle trafficking of junctional components by the exocyst complex has been proposed to promote junctional rearrangements during epithelial remodelling, but the receptors that allow exocyst docking to the target membranes remain poorly understood. Here, we show that the adherens junction component Ras Association domain family 8 (RASSF8) is required for the epithelial re-ordering that occurs during Drosophila pupal wing proximo-distal elongation. We identify the exocyst component Sec15 as a RASSF8 interactor. Loss of RASSF8 elicits cytoplasmic accumulation of Sec15 and Rab11-containing vesicles. These vesicles also contain the nectin-like homophilic adhesion molecule Echinoid, the depletion of which phenocopies the wing elongation and epithelial packing defects observed in RASSF8 mutants. Thus, our results suggest that RASSF8 promotes exocyst-dependent docking of Echinoid-containing vesicles during morphogenesis.
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Affiliation(s)
- Eunice H. Y. Chan
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Yanxiang Zhou
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Birgit L. Aerne
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Maxine V. Holder
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Anne Weston
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David J. Barry
- Advanced Light Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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40
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Herath TUB, Roy A, Gianfelice A, Ireton K. Shigella flexneri subverts host polarized exocytosis to enhance cell-to-cell spread. Mol Microbiol 2021; 116:1328-1346. [PMID: 34608697 DOI: 10.1111/mmi.14827] [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: 08/08/2021] [Revised: 09/21/2021] [Accepted: 10/01/2021] [Indexed: 11/28/2022]
Abstract
Shigella flexneri is a gram-negative bacterial pathogen that causes dysentery. Critical for disease is the ability of Shigella to use an actin-based motility (ABM) process to spread between cells of the colonic epithelium. ABM transports bacteria to the periphery of host cells, allowing the formation of plasma membrane protrusions that mediate spread to adjacent cells. Here we demonstrate that efficient protrusion formation and cell-to-cell spread of Shigella involves bacterial stimulation of host polarized exocytosis. Using an exocytic probe, we found that exocytosis is locally upregulated in bacterial protrusions in a manner that depends on the Shigella type III secretion system. Experiments involving RNA interference (RNAi) indicate that efficient bacterial protrusion formation and spread require the exocyst, a mammalian multi-protein complex known to mediate polarized exocytosis. In addition, the exocyst component Exo70 and the exocyst regulator RalA were recruited to Shigella protrusions, suggesting that bacteria manipulate exocyst function. Importantly, RNAi-mediated depletion of exocyst proteins or RalA reduced the frequency of protrusion formation and also the lengths of protrusions, demonstrating that the exocyst controls both the initiation and elongation of protrusions. Collectively, our results reveal that Shigella co-opts the exocyst complex to disseminate efficiently in host cell monolayers.
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Affiliation(s)
- Thilina U B Herath
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Arpita Roy
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Antonella Gianfelice
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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41
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Levic DS, Yamaguchi N, Wang S, Knaut H, Bagnat M. Knock-in tagging in zebrafish facilitated by insertion into non-coding regions. Development 2021; 148:dev199994. [PMID: 34495314 PMCID: PMC8513609 DOI: 10.1242/dev.199994] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/27/2021] [Indexed: 11/20/2022]
Abstract
Zebrafish provide an excellent model for in vivo cell biology studies because of their amenability to live imaging. Protein visualization in zebrafish has traditionally relied on overexpression of fluorescently tagged proteins from heterologous promoters, making it difficult to recapitulate endogenous expression patterns and protein function. One way to circumvent this problem is to tag the proteins by modifying their endogenous genomic loci. Such an approach is not widely available to zebrafish researchers because of inefficient homologous recombination and the error-prone nature of targeted integration in zebrafish. Here, we report a simple approach for tagging proteins in zebrafish on their N or C termini with fluorescent proteins by inserting PCR-generated donor amplicons into non-coding regions of the corresponding genes. Using this approach, we generated endogenously tagged alleles for several genes that are crucial for epithelial biology and organ development, including the tight junction components ZO-1 and Cldn15la, the trafficking effector Rab11a, the apical polarity protein aPKC and the ECM receptor Integrin β1b. Our approach facilitates the generation of knock-in lines in zebrafish, opening the way for accurate quantitative imaging studies.
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Affiliation(s)
- Daniel S. Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Naoya Yamaguchi
- Skirball Institute of Biomolecular Medicine, New York University Grossman School of Medicine, Department of Cell Biology, New York, NY 10016, USA
| | - Siyao Wang
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Holger Knaut
- Skirball Institute of Biomolecular Medicine, New York University Grossman School of Medicine, Department of Cell Biology, New York, NY 10016, USA
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
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42
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An SJ, Rivera-Molina F, Anneken A, Xi Z, McNellis B, Polejaev VI, Toomre D. An active tethering mechanism controls the fate of vesicles. Nat Commun 2021; 12:5434. [PMID: 34521845 PMCID: PMC8440521 DOI: 10.1038/s41467-021-25465-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/05/2021] [Indexed: 11/09/2022] Open
Abstract
Vesicle tethers are thought to underpin the efficiency of intracellular fusion by bridging vesicles to their target membranes. However, the interplay between tethering and fusion has remained enigmatic. Here, through optogenetic control of either a natural tether-the exocyst complex-or an artificial tether, we report that tethering regulates the mode of fusion. We find that vesicles mainly undergo kiss-and-run instead of full fusion in the absence of functional exocyst. Full fusion is rescued by optogenetically restoring exocyst function, in a manner likely dependent on the stoichiometry of tether engagement with the plasma membrane. In contrast, a passive artificial tether produces mostly kissing events, suggesting that kiss-and-run is the default mode of vesicle fusion. Optogenetic control of tethering further shows that fusion mode has physiological relevance since only full fusion could trigger lamellipodial expansion. These findings demonstrate that active coupling between tethering and fusion is critical for robust membrane merger.
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Affiliation(s)
- Seong J An
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Alexander Anneken
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Zhiqun Xi
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Brian McNellis
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Vladimir I Polejaev
- International Science and Technology Center, Yale University School of Medicine, New Haven, CT, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
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Abstract
The molecular mechanisms of cellular insulin action have been the focus of much investigation since the discovery of the hormone 100 years ago. Insulin action is impaired in metabolic syndrome, a condition known as insulin resistance. The actions of the hormone are initiated by binding to its receptor on the surface of target cells. The receptor is an α2β2 heterodimer that binds to insulin with high affinity, resulting in the activation of its tyrosine kinase activity. Once activated, the receptor can phosphorylate a number of intracellular substrates that initiate discrete signaling pathways. The tyrosine phosphorylation of some substrates activates phosphatidylinositol-3-kinase (PI3K), which produces polyphosphoinositides that interact with protein kinases, leading to activation of the kinase Akt. Phosphorylation of Shc leads to activation of the Ras/MAP kinase pathway. Phosphorylation of SH2B2 and of Cbl initiates activation of G proteins such as TC10. Activation of Akt and other protein kinases produces phosphorylation of a variety of substrates, including transcription factors, GTPase-activating proteins, and other kinases that control key metabolic events. Among the cellular processes controlled by insulin are vesicle trafficking, activities of metabolic enzymes, transcriptional factors, and degradation of insulin itself. Together these complex processes are coordinated to ensure glucose homeostasis.
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44
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Plasma membrane phospholipid signature recruits the plant exocyst complex via the EXO70A1 subunit. Proc Natl Acad Sci U S A 2021; 118:2105287118. [PMID: 34470819 DOI: 10.1073/pnas.2105287118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polarized exocytosis is essential for many vital processes in eukaryotic cells, where secretory vesicles are targeted to distinct plasma membrane domains characterized by their specific lipid-protein composition. Heterooctameric protein complex exocyst facilitates the vesicle tethering to a target membrane and is a principal cell polarity regulator in eukaryotes. The architecture and molecular details of plant exocyst and its membrane recruitment have remained elusive. Here, we show that the plant exocyst consists of two modules formed by SEC3-SEC5-SEC6-SEC8 and SEC10-SEC15-EXO70-EXO84 subunits, respectively, documenting the evolutionarily conserved architecture within eukaryotes. In contrast to yeast and mammals, the two modules are linked by a plant-specific SEC3-EXO70 interaction, and plant EXO70 functionally dominates over SEC3 in the exocyst recruitment to the plasma membrane. Using an interdisciplinary approach, we found that the C-terminal part of EXO70A1, the canonical EXO70 isoform in Arabidopsis, is critical for this process. In contrast to yeast and animal cells, the EXO70A1 interaction with the plasma membrane is mediated by multiple anionic phospholipids uniquely contributing to the plant plasma membrane identity. We identified several evolutionary conserved EXO70 lysine residues and experimentally proved their importance for the EXO70A1-phospholipid interactions. Collectively, our work has uncovered plant-specific features of the exocyst complex and emphasized the importance of the specific protein-lipid code for the recruitment of peripheral membrane proteins.
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45
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Zhang W, Huang L, Zhang C, Staiger CJ. Arabidopsis myosin XIK interacts with the exocyst complex to facilitate vesicle tethering during exocytosis. THE PLANT CELL 2021; 33:2454-2478. [PMID: 33871640 PMCID: PMC8364239 DOI: 10.1093/plcell/koab116] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 04/13/2021] [Indexed: 05/17/2023]
Abstract
Myosin motors are essential players in secretory vesicle trafficking and exocytosis in yeast and mammalian cells; however, similar roles in plants remain a matter for debate, at least for diffusely growing cells. Here, we demonstrate that Arabidopsis (Arabidopsis thaliana) myosin XIK, via its globular tail domain (GTD), participates in the vesicle tethering step of exocytosis through direct interactions with the exocyst complex. Specifically, myosin XIK GTD bound directly to several exocyst subunits in vitro and functional fluorescently tagged XIK colocalized with multiple exocyst subunits at plasma membrane (PM)-associated stationary foci. Moreover, genetic and pharmacological inhibition of myosin XI activity reduced the rate of appearance and lifetime of stationary exocyst complexes at the PM. By tracking single exocytosis events of cellulose synthase (CESA) complexes with high spatiotemporal resolution imaging and pair-wise colocalization of myosin XIK, exocyst subunits, and CESA6, we demonstrated that XIK associates with secretory vesicles earlier than exocyst and is required for the efficient localization and normal dynamic behavior of exocyst complex at the PM tethering site. This study reveals an important functional role for myosin XI in secretion and provides insights about the dynamic regulation of exocytosis in plants.
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Affiliation(s)
- Weiwei Zhang
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
| | - Lei Huang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Chunhua Zhang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
- Center for Plant Biology, College of Agriculture, Purdue University, West Lafayette, Indiana 47907, USA
| | - Christopher J. Staiger
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
- Center for Plant Biology, College of Agriculture, Purdue University, West Lafayette, Indiana 47907, USA
- Author for correspondence:
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Zaman A, Wu X, Lemoff A, Yadavalli S, Lee J, Wang C, Cooper J, McMillan EA, Yeaman C, Mirzaei H, White MA, Bivona TG. Exocyst protein subnetworks integrate Hippo and mTOR signaling to promote virus detection and cancer. Cell Rep 2021; 36:109491. [PMID: 34348154 DOI: 10.1016/j.celrep.2021.109491] [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: 12/02/2020] [Revised: 05/20/2021] [Accepted: 07/14/2021] [Indexed: 11/25/2022] Open
Abstract
The exocyst is an evolutionarily conserved protein complex that regulates vesicular trafficking and scaffolds signal transduction. Key upstream components of the exocyst include monomeric RAL GTPases, which help mount cell-autonomous responses to trophic and immunogenic signals. Here, we present a quantitative proteomics-based characterization of dynamic and signal-dependent exocyst protein interactomes. Under viral infection, an Exo84 exocyst subcomplex assembles the immune kinase Protein Kinase R (PKR) together with the Hippo kinase Macrophage Stimulating 1 (MST1). PKR phosphorylates MST1 to activate Hippo signaling and inactivate Yes Associated Protein 1 (YAP1). By contrast, a Sec5 exocyst subcomplex recruits another immune kinase, TANK binding kinase 1 (TBK1), which interacted with and activated mammalian target of rapamycin (mTOR). RALB was necessary and sufficient for induction of Hippo and mTOR signaling through parallel exocyst subcomplex engagement, supporting the cellular response to virus infection and oncogenic signaling. This study highlights RALB-exocyst signaling subcomplexes as mechanisms for the integrated engagement of Hippo and mTOR signaling in cells challenged by viral pathogens or oncogenic signaling.
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Affiliation(s)
- Aubhishek Zaman
- Department of Medicine, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA; UCSF Helen Diller Comprehensive Cancer Center, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA.
| | - Xiaofeng Wu
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Andrew Lemoff
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Sivaramakrishna Yadavalli
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Jeon Lee
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA; Bioinformatics Core Facility, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Chensu Wang
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Jonathan Cooper
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Elizabeth A McMillan
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Charles Yeaman
- Department of Anatomy and Cell Biology, University of Iowa, 51 Newton Road, Iowa City, IA 52242, USA
| | - Hamid Mirzaei
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Michael A White
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Trever G Bivona
- Department of Medicine, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA; UCSF Helen Diller Comprehensive Cancer Center, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA.
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47
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Loss of the exocyst complex component EXOC3 promotes hemostasis and accelerates arterial thrombosis. Blood Adv 2021; 5:674-686. [PMID: 33560379 DOI: 10.1182/bloodadvances.2020002515] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/28/2020] [Indexed: 11/20/2022] Open
Abstract
The exocyst is an octameric complex comprising 8 distinct protein subunits, exocyst complex components (EXOC) 1 to 8. It has an established role in tethering secretory vesicles to the plasma membrane, but its relevance to platelet granule secretion and function remains to be determined. Here, EXOC3 conditional knockout (KO) mice in the megakaryocyte/platelet lineage were generated to assess exocyst function in platelets. Significant defects in platelet aggregation, integrin activation, α-granule (P-selectin and platelet factor 4), dense granule, and lysosomal granule secretion were detected in EXOC3 KO platelets after treatment with a glycoprotein VI (GPVI)-selective agonist, collagen-related peptide (CRP). Except for P-selectin exposure, these defects were completely recovered by maximal CRP concentrations. GPVI surface levels were also significantly decreased by 14.5% in KO platelets, whereas defects in proximal GPVI signaling responses, Syk and LAT phosphorylation, and calcium mobilization were also detected, implying an indirect mechanism for these recoverable defects due to decreased surface GPVI. Paradoxically, dense granule secretion, integrin activation, and changes in surface expression of integrin αIIb (CD41) were significantly increased in KO platelets after protease-activated receptor 4 activation, but calcium responses were unaltered. Elevated integrin activation responses were completely suppressed with a P2Y12 receptor antagonist, suggesting enhanced dense granule secretion of adenosine 5'-diphosphate as a critical mediator of these responses. Finally, arterial thrombosis was significantly accelerated in KO mice, which also displayed improved hemostasis determined by reduced tail bleeding times. These findings reveal a regulatory role for the exocyst in controlling critical aspects of platelet function pertinent to thrombosis and hemostasis.
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48
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Osawa Y, Murata K, Usui M, Kuba Y, Le HT, Mikami N, Nakagawa T, Daitoku Y, Kato K, Shawki HH, Ikeda Y, Kuno A, Morimoto K, Tanimoto Y, Dinh TTH, Yagami KI, Ema M, Yoshida S, Takahashi S, Mizuno S, Sugiyama F. EXOC1 plays an integral role in spermatogonia pseudopod elongation and spermatocyte stable syncytium formation in mice. eLife 2021; 10:59759. [PMID: 33973520 PMCID: PMC8112867 DOI: 10.7554/elife.59759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 04/21/2021] [Indexed: 11/13/2022] Open
Abstract
The male germ cells must adopt the correct morphology at each differentiation stage for proper spermatogenesis. The spermatogonia regulates its differentiation state by its own migration. The male germ cells differentiate and mature with the formation of syncytia, failure of forming the appropriate syncytia results in the arrest at the spermatocyte stage. However, the detailed molecular mechanisms of male germ cell morphological regulation are unknown. Here, we found that EXOC1, a member of the Exocyst complex, is important for the pseudopod formation of spermatogonia and spermatocyte syncytia in mice. EXOC1 contributes to the pseudopod formation of spermatogonia by inactivating the Rho family small GTPase Rac1 and also functions in the spermatocyte syncytia with the SNARE proteins STX2 and SNAP23. Since EXOC1 is known to bind to several cell morphogenesis factors, this study is expected to be the starting point for the discovery of many morphological regulators of male germ cells.
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Affiliation(s)
- Yuki Osawa
- Master's Program in Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kazuya Murata
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Miho Usui
- School of Medical Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yumeno Kuba
- Master's Program in Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hoai Thu Le
- Ph.D Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
| | - Natsuki Mikami
- Ph.D Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
| | - Toshinori Nakagawa
- Division of Germ Cell Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (Sokendai), Okazaki, Japan
| | - Yoko Daitoku
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Kanako Kato
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Hossam Hassan Shawki
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yoshihisa Ikeda
- Doctoral program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Akihiro Kuno
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan.,Ph.D Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
| | - Kento Morimoto
- Doctoral program in Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yoko Tanimoto
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Tra Thi Huong Dinh
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Ken-Ichi Yagami
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Masatsugu Ema
- Department of Stem Cells and Human Disease Models, Research Center for Animal Life Science, Shiga University of Medical Science, Otsu, Japan
| | - Shosei Yoshida
- Division of Germ Cell Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (Sokendai), Okazaki, Japan
| | - Satoru Takahashi
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Seiya Mizuno
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Fumihiro Sugiyama
- Laboratory Animal Resource Center, Trans-border Medical Research Center, University of Tsukuba, Tsukuba, Japan
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49
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Brillada C, Teh OK, Ditengou FA, Lee CW, Klecker T, Saeed B, Furlan G, Zietz M, Hause G, Eschen-Lippold L, Hoehenwarter W, Lee J, Ott T, Trujillo M. Exocyst subunit Exo70B2 is linked to immune signaling and autophagy. THE PLANT CELL 2021; 33:404-419. [PMID: 33630076 PMCID: PMC8136888 DOI: 10.1093/plcell/koaa022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/18/2020] [Indexed: 05/08/2023]
Abstract
During the immune response, activation of the secretory pathway is key to mounting an effective response, while gauging its output is important to maintain cellular homeostasis. The Exo70 subunit of the exocyst functions as a spatiotemporal regulator by mediating numerous interactions with proteins and lipids. However, a molecular understanding of the exocyst regulation remains challenging. We show that, in Arabidopsis thaliana, Exo70B2 behaves as a bona fide exocyst subunit. Conversely, treatment with the salicylic acid (SA) defence hormone analog benzothiadiazole (BTH), or the immunogenic peptide flg22, induced Exo70B2 transport into the vacuole. We reveal that Exo70B2 interacts with AUTOPHAGY-RELATED PROTEIN 8 (ATG8) via two ATG8-interacting motives (AIMs) and its transport into the vacuole is dependent on autophagy. In line with its role in immunity, we discovered that Exo70B2 interacted with and was phosphorylated by the kinase MPK3. Mimicking phosphorylation had a dual impact on Exo70B2: first, by inhibiting localization at sites of active secretion, and second, it increased the interaction with ATG8. Phosphonull variants displayed higher effector-triggered immunity (ETI) and were hypersensitive to BTH, which induce secretion and autophagy. Our results suggest a molecular mechanism by which phosphorylation diverts Exo70B2 from the secretory into the autophagy pathway for its degradation, to dampen secretory activity.
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Affiliation(s)
- Carla Brillada
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Ooi-Kock Teh
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
- Department of Biological Science, School of Science, Hokkaido University, 060-0810 Sapporo, Japan
- Institute for the Advancement of Higher Education, Hokkaido University, 060-0815 Sapporo, Japan
| | | | - Chil-Woo Lee
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Till Klecker
- Institute of Cell Biology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Bushra Saeed
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Giulia Furlan
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Marco Zietz
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Gerd Hause
- Biozentrum, Martin-Luther-University Halle-Wittenberg, Halle 06120 (Saale), Germany
| | | | | | - Justin Lee
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Thomas Ott
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
- CIBSS—Centre for Integrative Biological Signalling Studies, University of Freiburg, 79085 Freiburg, Germany
| | - Marco Trujillo
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
- Author for communication:
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50
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Van Bergen NJ, Ahmed SM, Collins F, Cowley M, Vetro A, Dale RC, Hock DH, de Caestecker C, Menezes M, Massey S, Ho G, Pisano T, Glover S, Gusman J, Stroud DA, Dinger M, Guerrini R, Macara IG, Christodoulou J. Mutations in the exocyst component EXOC2 cause severe defects in human brain development. J Exp Med 2021; 217:151928. [PMID: 32639540 PMCID: PMC7537385 DOI: 10.1084/jem.20192040] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/03/2020] [Accepted: 04/03/2020] [Indexed: 12/30/2022] Open
Abstract
The exocyst, an octameric protein complex, is an essential component of the membrane transport machinery required for tethering and fusion of vesicles at the plasma membrane. We report pathogenic variants in an exocyst subunit, EXOC2 (Sec5). Affected individuals have severe developmental delay, dysmorphism, and brain abnormalities; variability associated with epilepsy; and poor motor skills. Family 1 had two offspring with a homozygous truncating variant in EXOC2 that leads to nonsense-mediated decay of EXOC2 transcript, a severe reduction in exocytosis and vesicle fusion, and undetectable levels of EXOC2 protein. The patient from Family 2 had a milder clinical phenotype and reduced exocytosis. Cells from both patients showed defective Arl13b localization to the primary cilium. The discovery of mutations that partially disable exocyst function provides valuable insight into this essential protein complex in neural development. Since EXOC2 and other exocyst complex subunits are critical to neuronal function, our findings suggest that EXOC2 variants are the cause of the patients’ neurological disorders.
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Affiliation(s)
- Nicole J Van Bergen
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Syed Mukhtar Ahmed
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Felicity Collins
- Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Medical Genomics Department, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Mark Cowley
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.,St Vincent's Clinical School, University of New South Wales Sydney, Sydney, New South Wales, Australia.,Children's Cancer Institute, Kensington, New South Wales, Australia
| | - Annalisa Vetro
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Russell C Dale
- Department of Paediatric Neurology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Kids Neuroscience Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Daniella H Hock
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Christian de Caestecker
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Minal Menezes
- Kids Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Sean Massey
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Gladys Ho
- Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Tiziana Pisano
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Seana Glover
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Jovanka Gusman
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - David A Stroud
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Marcel Dinger
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington Campus, Sydney, New South Wales, Australia
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Ian G Macara
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - John Christodoulou
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Victorian Clinical Genetics Services, Royal Children's Hospital, Parkville, Victoria, Australia
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