1
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Zhou N, Li X, Zheng Z, Liu J, Downie JA, Xie F. RinRK1 enhances NF receptors accumulation in nanodomain-like structures at root-hair tip. Nat Commun 2024; 15:3568. [PMID: 38670968 PMCID: PMC11053012 DOI: 10.1038/s41467-024-47794-4] [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: 03/09/2023] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Legume-rhizobia root-nodule symbioses involve the recognition of rhizobial Nod factor (NF) signals by NF receptors, triggering both nodule organogenesis and rhizobial infection. RinRK1 is induced by NF signaling and is essential for infection thread (IT) formation in Lotus japonicus. However, the precise mechanism underlying this process remains unknown. Here, we show that RinRK1 interacts with the extracellular domains of NF receptors (NFR1 and NFR5) to promote their accumulation at root hair tips in response to rhizobia or NFs. Furthermore, Flotillin 1 (Flot1), a nanodomain-organizing protein, associates with the kinase domains of NFR1, NFR5 and RinRK1. RinRK1 promotes the interactions between Flot1 and NF receptors and both RinRK1 and Flot1 are necessary for the accumulation of NF receptors at root hair tips upon NF stimulation. Our study shows that RinRK1 and Flot1 play a crucial role in NF receptor complex assembly within localized plasma membrane signaling centers to promote symbiotic infection.
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Affiliation(s)
- Ning Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Xiaolin Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Zhiqiong Zheng
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jing Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - J Allan Downie
- John Innes Centre, Norwich Research Park, NR4 7UH, Norwich, UK
| | - Fang Xie
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
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2
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McClellan B, Wilson CN, Brenner AJ, Jolly CA, deGraffenried L. Flotillin-1 palmitoylation is essential for its stability and subsequent tumor promoting capabilities. Oncogene 2024; 43:1063-1074. [PMID: 38374406 DOI: 10.1038/s41388-024-02946-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/02/2024] [Accepted: 01/08/2024] [Indexed: 02/21/2024]
Abstract
Flotillin-1 contributes to invasion and metastasis in triple negative breast cancer (TNBC) and is modified post-translationally through palmitoylation. Palmitoylation, the process of conjugating palmitoyl-CoA to proteins, plays an essential role in protein stability and trafficking. Thus far, there has not been any investigation into the role of flotillin-1 palmitoylation in the context of metastasis in vivo. To address the role of flotillin-1 palmitoylation in metastasis, MDA-MB-231 cells expressing palmitoylation defective flotillin-1 constructs were used as models. Compared to flotillin-1 WT expressing tumors, flotillin-1 palmitoylation defective displayed abrogated tumor progression and lung metastasis in vivo in both spontaneous and experimental models. Further mechanistic investigation led to the identification of zDHHC5 as the main palmitoyl acyltransferase responsible for palmitoylating endogenous flotillin-1. Modulation of flotillin-1 palmitoylation status through mutagenesis, zDHHC5 silencing, and 2-bromopalmitate inhibition all resulted in the proteasomal degradation of flotillin-1 protein. To assess if flotillin-1 palmitoylation can be inhibited for potential clinical relevance, we designed a competitive peptide fused to a cell penetrating peptide sequence, which displayed efficacy in blocking flotillin-1 palmitoylation in vitro without altering palmitoylation of other zDHHC5 substrates, highlighting its specificity. Additionally, TNBC xenograft tumor models expressing a doxycycline inducible flotillin-1 palmitoylation inhibiting peptide displayed attenuated tumor growth and lung metastasis. Collectively, these results reveal a novel palmitoylation dependent mechanism which is essential for the stability of flotillin-1 protein. More specifically, disruption of flotillin-1 palmitoylation through mutagenesis or competitive peptide promoted flotillin-1 protein degradation, subsequently impeding its tumor promoting and metastasis-inducing effects in TNBC tumor models.
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Affiliation(s)
- Bryan McClellan
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, TX, USA
| | - Crystal N Wilson
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, TX, USA
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Andrew J Brenner
- Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, USA
- Division of Hematology and Oncology, Department of Medicine, University of Texas Health Science Center, San Antonio, TX, USA
| | - Christopher A Jolly
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, TX, USA
- Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, USA
| | - Linda deGraffenried
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, TX, USA.
- Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, USA.
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3
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Samhan-Arias AK, Poejo J, Marques-da-Silva D, Martínez-Costa OH, Gutierrez-Merino C. Are There Lipid Membrane-Domain Subtypes in Neurons with Different Roles in Calcium Signaling? Molecules 2023; 28:7909. [PMID: 38067638 PMCID: PMC10708093 DOI: 10.3390/molecules28237909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/24/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
Lipid membrane nanodomains or lipid rafts are 10-200 nm diameter size cholesterol- and sphingolipid-enriched domains of the plasma membrane, gathering many proteins with different roles. Isolation and characterization of plasma membrane proteins by differential centrifugation and proteomic studies have revealed a remarkable diversity of proteins in these domains. The limited size of the lipid membrane nanodomain challenges the simple possibility that all of them can coexist within the same lipid membrane domain. As caveolin-1, flotillin isoforms and gangliosides are currently used as neuronal lipid membrane nanodomain markers, we first analyzed the structural features of these components forming nanodomains at the plasma membrane since they are relevant for building supramolecular complexes constituted by these molecular signatures. Among the proteins associated with neuronal lipid membrane nanodomains, there are a large number of proteins that play major roles in calcium signaling, such as ionotropic and metabotropic receptors for neurotransmitters, calcium channels, and calcium pumps. This review highlights a large variation between the calcium signaling proteins that have been reported to be associated with isolated caveolin-1 and flotillin-lipid membrane nanodomains. Since these calcium signaling proteins are scattered in different locations of the neuronal plasma membrane, i.e., in presynapses, postsynapses, axonal or dendritic trees, or in the neuronal soma, our analysis suggests that different lipid membrane-domain subtypes should exist in neurons. Furthermore, we conclude that classification of lipid membrane domains by their content in calcium signaling proteins sheds light on the roles of these domains for neuronal activities that are dependent upon the intracellular calcium concentration. Some examples described in this review include the synaptic and metabolic activity, secretion of neurotransmitters and neuromodulators, neuronal excitability (long-term potentiation and long-term depression), axonal and dendritic growth but also neuronal cell survival and death.
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Affiliation(s)
- Alejandro K. Samhan-Arias
- Departamento de Bioquímica, Universidad Autónoma de Madrid (UAM), C/Arturo Duperier 4, 28029 Madrid, Spain;
- Instituto de Investigaciones Biomédicas ‘Sols-Morreale’ (CSIC-UAM), C/Arturo Duperier 4, 28029 Madrid, Spain
| | - Joana Poejo
- Instituto de Biomarcadores de Patologías Moleculares, Universidad de Extremadura, 06006 Badajoz, Spain;
| | - Dorinda Marques-da-Silva
- LSRE—Laboratory of Separation and Reaction Engineering and LCM—Laboratory of Catalysis and Materials, School of Management and Technology, Polytechnic Institute of Leiria, Morro do Lena-Alto do Vieiro, 2411-901 Leiria, Portugal;
- ALiCE—Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
- School of Technology and Management, Polytechnic Institute of Leiria, Morro do Lena-Alto do Vieiro, 2411-901 Leiria, Portugal
| | - Oscar H. Martínez-Costa
- Departamento de Bioquímica, Universidad Autónoma de Madrid (UAM), C/Arturo Duperier 4, 28029 Madrid, Spain;
- Instituto de Investigaciones Biomédicas ‘Sols-Morreale’ (CSIC-UAM), C/Arturo Duperier 4, 28029 Madrid, Spain
| | - Carlos Gutierrez-Merino
- Instituto de Biomarcadores de Patologías Moleculares, Universidad de Extremadura, 06006 Badajoz, Spain;
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4
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Zhan Z, Ye M, Jin X. The roles of FLOT1 in human diseases (Review). Mol Med Rep 2023; 28:212. [PMID: 37772385 PMCID: PMC10552069 DOI: 10.3892/mmr.2023.13099] [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: 05/11/2023] [Accepted: 07/25/2023] [Indexed: 09/30/2023] Open
Abstract
FLOT1, a scaffold protein of lipid rafts, is involved in several biological processes, including lipid raft protein‑-dependent or clathrin‑independent endocytosis, and the formation of hippocampal synapses, amongst others. Increasing evidence has shown that FLOT1 can function as both a cancer promoter and cancer suppressor dependent on the type of cancer. FLOT1 can affect the occurrence and development of several types of cancer by affecting epithelial‑mesenchymal transition, proliferation of cancer cells, and relevant signaling pathways, and is regulated by long intergenic non‑coding RNAs or microRNAs. In the nervous system, overexpression or abnormally low expression of FLOT1 may lead to the occurrence of neurological diseases, such as Alzheimer's disease, Parkinson's disease, major depressive disorder and other diseases. Additionally, it is also associated with dilated cardiomyopathy, pathogenic microbial infection, diabetes‑related diseases, and gynecological diseases, amongst other diseases. In the present review, the structure and localization of FLOT1, as well as the physiological processes it is involved in are reviewed, and then the upstream and downstream regulation of FLOT1 in human disease, particularly in different types of cancer and neurological diseases are discussed, with a focus on potentially targeting FLOT1 for the clinical treatment of several diseases.
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Affiliation(s)
- Ziqing Zhan
- Department of Oncology, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Science Health Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Meng Ye
- Department of Oncology, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Science Health Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Xiaofeng Jin
- Department of Oncology, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Science Health Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
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5
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Szewczyk-Roszczenko OK, Roszczenko P, Shmakova A, Finiuk N, Holota S, Lesyk R, Bielawska A, Vassetzky Y, Bielawski K. The Chemical Inhibitors of Endocytosis: From Mechanisms to Potential Clinical Applications. Cells 2023; 12:2312. [PMID: 37759535 PMCID: PMC10527932 DOI: 10.3390/cells12182312] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Endocytosis is one of the major ways cells communicate with their environment. This process is frequently hijacked by pathogens. Endocytosis also participates in the oncogenic transformation. Here, we review the approaches to inhibit endocytosis, discuss chemical inhibitors of this process, and discuss potential clinical applications of the endocytosis inhibitors.
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Affiliation(s)
| | - Piotr Roszczenko
- Department of Biotechnology, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland; (P.R.); (A.B.)
| | - Anna Shmakova
- CNRS, UMR 9018, Institut Gustave Roussy, Université Paris-Saclay, 94800 Villejuif, France;
| | - Nataliya Finiuk
- Department of Regulation of Cell Proliferation and Apoptosis, Institute of Cell Biology of National Academy of Sciences of Ukraine, Drahomanov 14/16, 79005 Lviv, Ukraine;
| | - Serhii Holota
- Department of Pharmaceutical, Organic and Bioorganic Chemistry, Danylo Halytsky Lviv National Medical University, Pekarska 69, 79010 Lviv, Ukraine; (S.H.); (R.L.)
| | - Roman Lesyk
- Department of Pharmaceutical, Organic and Bioorganic Chemistry, Danylo Halytsky Lviv National Medical University, Pekarska 69, 79010 Lviv, Ukraine; (S.H.); (R.L.)
| | - Anna Bielawska
- Department of Biotechnology, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland; (P.R.); (A.B.)
| | - Yegor Vassetzky
- CNRS, UMR 9018, Institut Gustave Roussy, Université Paris-Saclay, 94800 Villejuif, France;
| | - Krzysztof Bielawski
- Department of Synthesis and Technology of Drugs, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland;
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6
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Liu A, Ouyang X, Wang Z, Dong B. ELMOD3-Rab1A-Flotillin2 cascade regulates lumen formation via vesicle trafficking in Ciona notochord. Open Biol 2023; 13:220367. [PMID: 36918025 PMCID: PMC10014252 DOI: 10.1098/rsob.220367] [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] [Indexed: 03/16/2023] Open
Abstract
Lumen development is a crucial phase in tubulogenesis, although its molecular mechanisms are largely unknown. In this study, we discovered an ELMO domain-containing 3 (ELMOD3), which belongs to ADP-ribosylation factor GTPase-activating protein family, was necessary to form the notochord lumen in Ciona larvae. We demonstrated that ELMOD3 interacted with lipid raft protein Flotillin2 and regulated its subcellular localization. The loss-of-function of Flotillin2 prevented notochord lumen formation. Furthermore, we found that ELMOD3 also interacted with Rab1A, which is the regulatory GTPase for vesicle trafficking and located at the notochord cell surface. Rab1A mutations arrested the lumen formation, phenocopying the loss-of-function of ELMOD3 and Flotillin2. Our findings further suggested that Rab1A interactions influenced Flotillin2 localization. We thus identified a unique pathway in which ELMOD3 interacted with Rab1A, which controlled the Flotillin2-mediated vesicle trafficking from cytoplasm to apical membrane, required for Ciona notochord lumen formation.
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Affiliation(s)
- Amei Liu
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Xiuke Ouyang
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Zhuqing Wang
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Bo Dong
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
- Laoshan Laboratory, Qingdao 266237, People's Republic of China
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7
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Wang R, Chen Z, Zhang Y, Xiao S, Zhang W, Hu X, Xiao Q, Liu Q, Wang X. Flotillin-1 is a prognostic biomarker for glioblastoma and promotes cancer development through enhancing invasion and altering tumour microenvironment. J Cell Mol Med 2023; 27:392-402. [PMID: 36647700 PMCID: PMC9889621 DOI: 10.1111/jcmm.17660] [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: 09/28/2022] [Revised: 12/18/2022] [Accepted: 12/25/2022] [Indexed: 01/18/2023] Open
Abstract
Flotillin-1(FLOT1) has long been recognized as a tumour-promoting gene in several types of cancer. However, the expression and function of FLOT1 in glioblastomas (GBM) has not been elucidated. Here, in this study, we find that the expression level of FLOT1 in GBM tissue was much higher than that in normal brain, and the expression was even higher in the more aggressive subtypes and IDH status of glioma. Kaplan-Meier survival revealed that high FLOT1 expression is closely associated with poor outcome in GBM patients. FLOT1 knockdown markedly reduced the proliferation, migration and invasiveness of GBM cells, while FLOT1 overexpression significantly increases GBM cell proliferation, migration and invasiveness. Mechanistically, FLOT1 expression may play a potential role in the microenvironment of GBM. Therefore, FLOT1 promotes GBM proliferation and invasion in vitro and in vivo and may serve as a biomarker of prognosis and therapeutic potential in the fight against GBM.
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Affiliation(s)
- Ran Wang
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina,The Hunan Provincial Key Lab of Precision Diagnosis and Treatment for Gastrointestinal Tumor, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Zhikang Chen
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina,The Hunan Provincial Key Lab of Precision Diagnosis and Treatment for Gastrointestinal Tumor, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Yi Zhang
- Department of Neurosurgery, Dengzhou People's HospitalDengzhouHenanChina
| | - Shihan Xiao
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Wuming Zhang
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Xianqin Hu
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Qun Xiao
- Department of Neurosurgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Qing Liu
- Department of Neurosurgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Xiangyu Wang
- Department of Neurosurgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
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8
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Sphingosylphosphorylcholine (SPC), a Causative Factor of SPC-Induced Vascular Smooth Muscle Cells Contraction, Is Taken Up via Endocytosis. Cells 2023; 12:cells12020265. [PMID: 36672200 PMCID: PMC9857160 DOI: 10.3390/cells12020265] [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: 11/14/2022] [Revised: 12/21/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
The reaction field of abnormal vascular contraction induced by sphingosylphosphorylcholine (SPC) and the action point of SPC around the plasma membranes remain unknown. However, we found in a previous study that fisetin prevents SPC-induced vascular smooth muscle cells contraction, while the mechanism remains unknown. Therefore, in this study, we aimed to address the action point of SPC around the plasma membranes and the involvement of fisetin. We focused on microdomains and evaluated their markers flotillin-1 and caveolin-1 and the localization of SPC to investigate their action point. The results showed that microdomains of vascular smooth muscle cells were not involved in SPC-induced contraction. However, we found that after SPC had been affected on the plasma membrane, cells took up SPC via endocytosis. Moreover, SPC remained in the cells and did not undergo transcytosis, and SPC-induced contracting cells produced exosomes. These phenomena were similar to those observed in fisetin-treated cells. Thus, we speculated that, although not involved in the reaction field of SPC-induced contractions, the microdomain induced the endocytosis of SPCs, and fisetin prevented the contractions by directly targeting vascular smooth muscle cells. Notably, this preventive mechanism involves the cellular uptake of SPC via endocytosis.
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9
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Wisniewski DJ, Liyasova MS, Korrapati S, Zhang X, Ratnayake S, Chen Q, Gilbert SF, Catalano A, Voeller D, Meerzaman D, Guha U, Porat-Shliom N, Annunziata CM, Lipkowitz S. Flotillin-2 regulates epidermal growth factor receptor activation, degradation by Cbl-mediated ubiquitination, and cancer growth. J Biol Chem 2022; 299:102766. [PMID: 36470425 PMCID: PMC9823131 DOI: 10.1016/j.jbc.2022.102766] [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: 04/08/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 12/08/2022] Open
Abstract
Epidermal growth factor receptor (EGFR) signaling is frequently dysregulated in various cancers. The ubiquitin ligase Casitas B-lineage lymphoma proto-oncogene (Cbl) regulates degradation of activated EGFR through ubiquitination and acts as an adaptor to recruit proteins required for trafficking. Here, we used stable isotope labeling with amino acids in cell culture mass spectrometry to compare Cbl complexes with or without epidermal growth factor (EGF) stimulation. We identified over a hundred novel Cbl interactors, and a secondary siRNA screen found that knockdown of Flotillin-2 (FLOT2) led to increased phosphorylation and degradation of EGFR upon EGF stimulation in HeLa cells. In PC9 and H441 cells, FLOT2 knockdown increased EGF-stimulated EGFR phosphorylation, ubiquitination, and downstream signaling, reversible by EGFR inhibitor erlotinib. CRISPR knockout (KO) of FLOT2 in HeLa cells confirmed EGFR downregulation, increased signaling, and increased dimerization and endosomal trafficking. Furthermore, we determined that FLOT2 interacted with both Cbl and EGFR. EGFR downregulation upon FLOT2 loss was Cbl dependent, as coknockdown of Cbl and Cbl-b restored EGFR levels. In addition, FLOT2 overexpression decreased EGFR signaling and growth. Overexpression of wildtype (WT) FLOT2, but not the soluble G2A FLOT2 mutant, inhibited EGFR phosphorylation upon EGF stimulation in HEK293T cells. FLOT2 loss induced EGFR-dependent proliferation and anchorage-independent growth. Lastly, FLOT2 KO increased tumor formation and tumor volume in nude mice and NSG mice, respectively. Together, these data demonstrated that FLOT2 negatively regulated EGFR activation and dimerization, as well as its subsequent ubiquitination, endosomal trafficking, and degradation, leading to reduced proliferation in vitro and in vivo.
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Affiliation(s)
- David J Wisniewski
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Mariya S Liyasova
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Soumya Korrapati
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Xu Zhang
- Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Shashikala Ratnayake
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, Maryland, USA
| | - Qingrong Chen
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, Maryland, USA
| | - Samuel F Gilbert
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Alexis Catalano
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Donna Voeller
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Daoud Meerzaman
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, Maryland, USA
| | - Udayan Guha
- Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Natalie Porat-Shliom
- Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Christina M Annunziata
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Stanley Lipkowitz
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA.
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10
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Cross-linking of the endolysosomal system reveals potential flotillin structures and cargo. Nat Commun 2022; 13:6212. [PMID: 36266287 PMCID: PMC9584938 DOI: 10.1038/s41467-022-33951-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 10/06/2022] [Indexed: 12/24/2022] Open
Abstract
Lysosomes are well-established as the main cellular organelles for the degradation of macromolecules and emerging as regulatory centers of metabolism. They are of crucial importance for cellular homeostasis, which is exemplified by a plethora of disorders related to alterations in lysosomal function. In this context, protein complexes play a decisive role, regulating not only metabolic lysosomal processes but also lysosome biogenesis, transport, and interaction with other organelles. Using cross-linking mass spectrometry, we analyze lysosomes and early endosomes. Based on the identification of 5376 cross-links, we investigate protein-protein interactions and structures of lysosome- and endosome-related proteins. In particular, we present evidence for a tetrameric assembly of the lysosomal hydrolase PPT1 and a heterodimeric structure of FLOT1/FLOT2 at lysosomes and early endosomes. For FLOT1-/FLOT2-positive early endosomes, we identify >300 putative cargo proteins and confirm eleven substrates for flotillin-dependent endocytosis, including the latrophilin family of adhesion G protein-coupled receptors.
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11
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Amyloid β, Lipid Metabolism, Basal Cholinergic System, and Therapeutics in Alzheimer’s Disease. Int J Mol Sci 2022; 23:ijms232012092. [PMID: 36292947 PMCID: PMC9603563 DOI: 10.3390/ijms232012092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/04/2022] [Accepted: 10/06/2022] [Indexed: 12/05/2022] Open
Abstract
The presence of insoluble aggregates of amyloid β (Aβ) in the form of neuritic plaques (NPs) is one of the main features that define Alzheimer’s disease. Studies have suggested that the accumulation of these peptides in the brain significantly contributes to extensive neuronal loss. Furthermore, the content and distribution of cholesterol in the membrane have been shown to have an important effect on the production and subsequent accumulation of Aβ peptides in the plasma membrane, contributing to dysfunction and neuronal death. The monomeric forms of these membrane-bound peptides undergo several conformational changes, ranging from oligomeric forms to beta-sheet structures, each presenting different levels of toxicity. Aβ peptides can be internalized by particular receptors and trigger changes from Tau phosphorylation to alterations in cognitive function, through dysfunction of the cholinergic system. The goal of this review is to summarize the current knowledge on the role of lipids in Alzheimer’s disease and their relationship with the basal cholinergic system, as well as potential disease-modifying therapies.
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12
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Li S, Shi H, Ruan L, Liu L, Wang C. Molecular characterization and function of the lipid raft protein Lvflotillin-1A from Litopenaeus vannamei. FISH & SHELLFISH IMMUNOLOGY 2022; 128:380-388. [PMID: 35934241 DOI: 10.1016/j.fsi.2022.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/12/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
White spot syndrome virus (WSSV) can cause a contagious, high virulent and pandemic disease for crustaceans, especially shrimps. However, the molecular mechanism of WSSV pathogenesis remains unclear. Flotillins are lipid raft-associated proteins, which mainly include flotillin-1 and flotillin-2. They are involved in the formation of large heteromeric protein complexes engaged in diverse signalling pathways at the membrane-cytosol interface. They defined a clathrin-independent endocytic pathway in mammalian cells. Our previous studies suggested that shrimp flotillin-2 might mediate endocytosis involved in WSSV infection. To further explore the function of shrimp flotillin, a flotillin-1 homologous, Lvflotillin-1A was identified and characterized in Litopenaeus vanamei. The transcription of Lvflotillin-1A showed a significant decline at 12h post-infection, followed by complete recovery and a slight up-regulation after the WSSV challenge. Gene silencing revealed that inhibition of Lvflotillin-1A raised the virus infection, suggesting Lvflotillin-1A might play an important role in shrimp immunity. Furthermore, co-immunoprecipitation and immunofluorescence illustrated that Lvflotillin-1A and Lvflotillin-2 could form hetero-oligomers, and co-expression promoted the accumulation of intracellular vesicles. The study revealed that WSSV might up-regulate Lvflotillin-2 expression and alter the subcellular location of Lvflotillin-1 protein to facilitate virus infection. These results will provide information for understanding the interaction between WSSV and shrimp.
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Affiliation(s)
- Sujie Li
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Ministry of Natural Resources, Third Institute of Oceanography, Ministry of Natural Resources, Fujian Key Laboratory of Marine Genetic Resources, Xiamen, 361005, PR China
| | - Hong Shi
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Ministry of Natural Resources, Third Institute of Oceanography, Ministry of Natural Resources, Fujian Key Laboratory of Marine Genetic Resources, Xiamen, 361005, PR China.
| | - Lingwei Ruan
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Ministry of Natural Resources, Third Institute of Oceanography, Ministry of Natural Resources, Fujian Key Laboratory of Marine Genetic Resources, Xiamen, 361005, PR China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, PR China
| | - Linmin Liu
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Ministry of Natural Resources, Third Institute of Oceanography, Ministry of Natural Resources, Fujian Key Laboratory of Marine Genetic Resources, Xiamen, 361005, PR China
| | - Chuanqi Wang
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Ministry of Natural Resources, Third Institute of Oceanography, Ministry of Natural Resources, Fujian Key Laboratory of Marine Genetic Resources, Xiamen, 361005, PR China
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Gundu C, Arruri VK, Yadav P, Navik U, Kumar A, Amalkar VS, Vikram A, Gaddam RR. Dynamin-Independent Mechanisms of Endocytosis and Receptor Trafficking. Cells 2022; 11:cells11162557. [PMID: 36010634 PMCID: PMC9406725 DOI: 10.3390/cells11162557] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/03/2022] [Accepted: 08/13/2022] [Indexed: 11/16/2022] Open
Abstract
Endocytosis is a fundamental mechanism by which cells perform housekeeping functions. It occurs via a variety of mechanisms and involves many regulatory proteins. The GTPase dynamin acts as a “molecular scissor” to form endocytic vesicles and is a critical regulator among the proteins involved in endocytosis. Some GTPases (e.g., Cdc42, arf6, RhoA), membrane proteins (e.g., flotillins, tetraspanins), and secondary messengers (e.g., calcium) mediate dynamin-independent endocytosis. These pathways may be convergent, as multiple pathways exist in a single cell. However, what determines the specific path of endocytosis is complex and challenging to comprehend. This review summarizes the mechanisms of dynamin-independent endocytosis, the involvement of microRNAs, and factors that contribute to the cellular decision about the specific route of endocytosis.
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Affiliation(s)
- Chayanika Gundu
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad 500037, Telangana, India
| | - Vijay Kumar Arruri
- Department of Neurological Surgery, University of Wisconsin, Madison, WI 53792, USA
| | - Poonam Yadav
- Department of Pharmacology, Central University of Punjab, Bathinda 151001, Punjab, India
| | - Umashanker Navik
- Department of Pharmacology, Central University of Punjab, Bathinda 151001, Punjab, India
| | - Ashutosh Kumar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Kolkata 700054, West Bengal, India
| | - Veda Sudhir Amalkar
- Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Ajit Vikram
- Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Ravinder Reddy Gaddam
- Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
- Correspondence:
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Endocytosis-mediated vitellogenin absorption and lipid metabolism in the hindgut-derived placenta of the viviparous teleost Xenotoca eiseni. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159183. [PMID: 35660667 DOI: 10.1016/j.bbalip.2022.159183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/12/2022] [Accepted: 05/14/2022] [Indexed: 11/21/2022]
Abstract
Certain viviparous animals possess mechanisms for mother-to-embryo nutrient transport during gestation. Xenotoca eiseni is one such viviparous teleost species in which the mother supplies proteins and other components to the offspring developing in the ovary. The embryo possesses trophotaenia, hindgut-derived placental structure, to receive the maternal supplement. However, research on the molecular mechanisms underlying viviparous species is scarce in non-mammalian vertebrates, including teleosts. Thus, we conducted this study to investigate the mechanism for nutrient absorption and degradation in trophotaeniae of X. eiseni. A tracer assay indicated that a lipid transfer protein, vitellogenin (Vtg), was absorbed into the epithelial layer cells of the trophotaeniae. Vtg uptake was significantly suppressed by Pitstop-2, an inhibitor of clathrin-mediated endocytosis. Gene expression analysis indicated that the genes involved in endocytosis-mediated lipolysis and lysosomal cholesterol transport were expressed in the trophotaeniae. In contrast, plasma membrane transporters expressed in the intestinal tract were not functional in the trophotaeniae. Our results suggested that endocytosis-mediated lysosomal lipolysis is one of the mechanisms underlying maternal component metabolism. Thus, our study demonstrated how viviparous teleost species have acquired a unique developmental system that is based on the hindgut-derived placenta.
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Abstract
Flotillins 1 and 2 are two ubiquitous, highly conserved homologous proteins that assemble to form heterotetramers at the cytoplasmic face of the plasma membrane in cholesterol- and sphingolipid-enriched domains. Flotillin heterotetramers can assemble into large oligomers to form molecular scaffolds that regulate the clustering of at the plasma membrane and activity of several receptors. Moreover, flotillins are upregulated in many invasive carcinomas and also in sarcoma, and this is associated with poor prognosis and metastasis formation. When upregulated, flotillins promote plasma membrane invagination and induce an endocytic pathway that allows the targeting of cargo proteins in the late endosomal compartment in which flotillins accumulate. These late endosomes are not degradative, and participate in the recycling and secretion of protein cargos. The cargos of this Upregulated Flotillin–Induced Trafficking (UFIT) pathway include molecules involved in signaling, adhesion, and extracellular matrix remodeling, thus favoring the acquisition of an invasive cellular behavior leading to metastasis formation. Thus, flotillin presence from the plasma membrane to the late endosomal compartment influences the activity, and even modifies the trafficking and fate of key protein cargos, favoring the development of diseases, for instance tumors. This review summarizes the current knowledge on flotillins and their role in cancer development focusing on their function in cellular membrane remodeling and vesicular trafficking regulation.
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Huang CW, Chu PY, Wu YF, Chan WR, Wang YH. Identification of Functional SSR Markers in Freshwater Ornamental Shrimps Neocaridina denticulata Using Transcriptome Sequencing. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2020; 22:772-785. [PMID: 32529453 DOI: 10.1007/s10126-020-09979-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
The amazing colors and patterns are fascinating characteristics in all of the aquarium species. However, genetic and breeding molecular investigations of ornamental shrimps are rather limited. Here, we present the first transcriptomic analysis and application of microsatellites based on the chromatophore-encoded genes of Neocaridina denticulata to assist freshwater ornamental shrimp germplasm enhancement and its extensive applications. A total of 65,402 unigenes were annotated, and 4706 differentially expressed genes were screened and identified between super red shrimp and chocolate shrimp strains. Several gene ratios were examined to put in perspective possible genetic markers for the different strains of normal pigmentation development, including flotillin-2-like, keratin, the G protein-coupled receptor Mth2-like, annexin A7, and unconventional myosin-IXb-like. Five simple sequence repeat markers were effective for colored shrimps and were used to develop a marker-assisted selection platform for systematic breeding management program to maintain genetic diversity of the species. These markers could also be used to assist the identification of pure strains and increase the genetic stability of ornamental shrimp color phenotypes. Consequently, our results of microsatellite marker development are valuable for assisting shrimp genetic and selection breeding studies on freshwater ornamental shrimp and related crystal shrimp species.
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Affiliation(s)
- Chang-Wen Huang
- Department of Aquaculture, National Taiwan Ocean University, 2 Beining Road, Jhongjheng District, Keelung City, 20224, Taiwan.
- Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
| | - Pei-Yun Chu
- Department of Aquaculture, National Taiwan Ocean University, 2 Beining Road, Jhongjheng District, Keelung City, 20224, Taiwan
| | - Yu-Fang Wu
- Department of Aquaculture, National Taiwan Ocean University, 2 Beining Road, Jhongjheng District, Keelung City, 20224, Taiwan
| | - Wei-Ren Chan
- Department of Aquaculture, National Taiwan Ocean University, 2 Beining Road, Jhongjheng District, Keelung City, 20224, Taiwan
| | - Yeh-Hao Wang
- Larmax International Co., Ltd. No.9, Yuanxi 2nd Rd., Changzhi, Pingtung, Taiwan
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Flotillins: At the Intersection of Protein S-Palmitoylation and Lipid-Mediated Signaling. Int J Mol Sci 2020; 21:ijms21072283. [PMID: 32225034 PMCID: PMC7177705 DOI: 10.3390/ijms21072283] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 02/07/2023] Open
Abstract
Flotillin-1 and flotillin-2 are ubiquitously expressed, membrane-associated proteins involved in multifarious cellular events from cell signaling, endocytosis, and protein trafficking to gene expression. They also contribute to oncogenic signaling. Flotillins bind the cytosolic leaflet of the plasma membrane and endomembranes and, upon hetero-oligomerization, serve as scaffolds facilitating the assembly of multiprotein complexes at the membrane-cytosol interface. Additional functions unique to flotillin-1 have been discovered recently. The membrane-binding of flotillins is regulated by S-palmitoylation and N-myristoylation, hydrophobic interactions involving specific regions of the polypeptide chain and, to some extent, also by their oligomerization. All these factors endow flotillins with an ability to associate with the sphingolipid/cholesterol-rich plasma membrane domains called rafts. In this review, we focus on the critical input of lipids to the regulation of the flotillin association with rafts and thereby to their functioning. In particular, we discuss how the recent developments in the field of protein S-palmitoylation have contributed to the understanding of flotillin1/2-mediated processes, including endocytosis, and of those dependent exclusively on flotillin-1. We also emphasize that flotillins affect directly or indirectly the cellular levels of lipids involved in diverse signaling cascades, including sphingosine-1-phosphate and PI(4,5)P2. The mutual relations between flotillins and distinct lipids are key to the regulation of their involvement in numerous cellular processes.
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Targeted enhancement of flotillin-dependent endocytosis augments cellular uptake and impact of cytotoxic drugs. Sci Rep 2019; 9:17768. [PMID: 31780775 PMCID: PMC6882852 DOI: 10.1038/s41598-019-54062-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 11/07/2019] [Indexed: 12/23/2022] Open
Abstract
Cellular uptake is limiting for the efficacy of many cytotoxic drugs used to treat cancer. Identifying endocytic mechanisms that can be modulated with targeted, clinically-relevant interventions is important to enhance the efficacy of various cancer drugs. We identify that flotillin-dependent endocytosis can be targeted and upregulated by ultrasound and microbubble (USMB) treatments to enhance uptake and efficacy of cancer drugs such as cisplatin. USMB involves targeted ultrasound following administration of encapsulated microbubbles, used clinically for enhanced ultrasound image contrast. USMB treatments robustly enhanced internalization of the molecular scaffold protein flotillin, as well as flotillin-dependent fluid-phase internalization, a phenomenon dependent on the protein palmitoyltransferase DHHC5 and the Src-family kinase Fyn. USMB treatment enhanced DNA damage and cell killing elicited by the cytotoxic agent cisplatin in a flotillin-dependent manner. Thus, flotillin-dependent endocytosis can be modulated by clinically-relevant USMB treatments to enhance drug uptake and efficacy, revealing an important new strategy for targeted drug delivery for cancer treatment.
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Thalwieser Z, Király N, Fonódi M, Csortos C, Boratkó A. Protein phosphatase 2A-mediated flotillin-1 dephosphorylation up-regulates endothelial cell migration and angiogenesis regulation. J Biol Chem 2019; 294:20196-20206. [PMID: 31753918 DOI: 10.1074/jbc.ra119.007980] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 11/04/2019] [Indexed: 12/31/2022] Open
Abstract
Endothelial cells have key functions in endothelial barrier integrity and in responses to angiogenic signals that promote cell proliferation, cell migration, cytoskeletal reorganization, and formation of new blood vessels. These functions highly depend on protein-protein interactions in cell-cell junction and cell attachment complexes and on interactions with cytoskeletal proteins. Protein phosphatase 2A (PP2A) dephosphorylates several target proteins involved in cytoskeletal dynamics and cell adhesion. Our goal was to find new interacting and substrate proteins of the PP2A-B55α holoenzyme in bovine pulmonary endothelial cells. Using LC-MS/MS analysis, we identified flotillin-1 as a protein that binds recombinant GSH S-transferase-tagged PP2A-B55α. Immunoprecipitation experiments, proximity ligation assays, and immunofluorescent staining confirmed the interaction between these two endogenous proteins in endothelial cells. Originally, flotillins were described as regulatory proteins for axon regeneration, but they appear to function in many cellular processes, such as membrane receptor signaling, endocytosis, and cell adhesion. Ser315 is a known PKC-targeted site in flotillin-1. Utilizing phosphomutants of flotillin-1 and the NanoBiT luciferase assay, we show here that phosphorylation/dephosphorylation of Ser315 in flotillin-1 significantly affects its interaction with PP2A-B55α and that PP2A-B55α dephosphorylates phospho-Ser315 Spreading, attachment, migration, and in vitro tube formation rates of S315A variant-overexpressing cells were faster than those of nontransfected or S315D-transfected cells. These results indicate that the PP2A-flotillin-1 interaction identified here affects major physiological activities of pulmonary endothelial cells.
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Affiliation(s)
- Zsófia Thalwieser
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Nikolett Király
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Márton Fonódi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Csilla Csortos
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Anita Boratkó
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
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Vocelle D, Chan C, Walton SP. Endocytosis Controls siRNA Efficiency: Implications for siRNA Delivery Vehicle Design and Cell-Specific Targeting. Nucleic Acid Ther 2019; 30:22-32. [PMID: 31718426 DOI: 10.1089/nat.2019.0804] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
While small interfering RNAs (siRNAs) are commonly used for laboratory studies, development of siRNA therapeutics has been slower than expected, due, in part, to a still limited understanding of the endocytosis and intracellular trafficking of siRNA-containing complexes. With the recent characterization of multiple clathrin-/caveolin-independent endocytic pathways, that is, those mediated by Graf1, Arf6, and flotillin, it has become clear that the endocytic mechanism influences subsequent intracellular processing of the internalized cargo. To explore siRNA delivery in light of these findings, we developed a novel assay that differentiates uptake by each of the endocytic pathways and can be used to determine whether endocytosis by a pathway leads to the initiation of RNA interference (RNAi). Using Lipofectamine 2000 (LF2K), we determined the endocytosis pathway leading to active silencing (whether by clathrin, caveolin, Arf6, Graf1, flotillin, or macropinocytosis) across multiple cell types (HeLa, H1299, HEK293, and HepG2). We showed that LF2K is internalized by Graf1-, Arf6-, or flotillin-mediated endocytosis for the initiation of RNAi, depending on cell type. In addition, we found that a portion of siRNA-containing complexes is internalized by pathways that do not lead to initiation of silencing. Inhibition of these pathways enhanced intracellular levels of siRNAs with concomitant enhancement of silencing.
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Affiliation(s)
- Daniel Vocelle
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan
| | - Christina Chan
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan
| | - S Patrick Walton
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan
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Hanafusa K, Hayashi N. The Flot2 component of the lipid raft changes localization during neural differentiation of P19C6 cells. BMC Mol Cell Biol 2019; 20:38. [PMID: 31455216 PMCID: PMC6712619 DOI: 10.1186/s12860-019-0225-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 08/22/2019] [Indexed: 12/18/2022] Open
Abstract
Background Flotillin-2 (Flot2) is a lipid raft scaffold protein that is thought to be related to neural differentiation. Flot2 is phosphorylated by Fyn, a Src kinase, and causes raft-dependent endocytosis; however, the exact role of Flot2 in neural differentiation remains unclear. To reveal the roles of lipid raft-associated proteins during neural differentiation, we tried to analyze the expression and localization. Results In this study, we found that the expression levels of the Flot2 and Fyn proteins increased in whole-cell lysates of P19C6 cells after neural differentiation. In addition, sucrose density fractionation and immunofluorescence experiments revealed an increase in the localization of Flot2 and Fyn to lipid rafts after neural differentiation. We also found that Fyn partially colocalized with Flot2 lipid rafts in neural cells. Conclusion The observed distribution of Fyn and level of inactivated Fyn and/or c-Src in detergent–resistant membrane (DRM) fractions suggests that the amount of activated Fyn might increase in DRM fractions after neural differentiation. Overall these findings suggest that Flot2 lipid rafts are associated with Fyn, and that Fyn phosphorylates Flot2 during neural differentiation of P19C6 cells. Electronic supplementary material The online version of this article (10.1186/s12860-019-0225-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kei Hanafusa
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
| | - Nobuhiro Hayashi
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan.
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22
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Gao F, Wu H, Wang R, Guo Y, Zhang Z, Wang T, Zhang G, Liu C, Liu J. MicroRNA-485-5p suppresses the proliferation, migration and invasion of small cell lung cancer cells by targeting flotillin-2. Bioengineered 2019; 10:1-12. [PMID: 30836864 PMCID: PMC6527069 DOI: 10.1080/21655979.2019.1586056] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
This study is aimed to elucidate the mechanisms underlying the role of miR-485-5p in small cell lung cancer (SCLC). The expression of miR-485-5p were quantified with real time quantitative PCR and it was found that the level of miR-485-5p was lower in SCLC tissues than normal tissues. In cultured SCLC cell lines, overexpression of miR-485-5p reduced cell proliferation, migration, and invasion in vitro, whereas knockdown of miR-485-5p performed contrary. FLOT2 expression was obviously upregulated and negatively correlated with miR-485-5p expression level in SCLC tissues. Overexpression of miR-485-5p significantly inhibited the protein expression of flotillin-2 (FLOT2) in cultured SCLC cells. Luciferase reporter assay confirmed that FLOT2 was a direct target of miR-485-5p in SCLC cells. It is concluded that miR-485-5p, as a tumor suppressor, inhibits the growth and metastasis in SCLC by targeting FLOT2. Upregulation of miR-485-5p expression may be an attractive strategy for SCLC therapy.
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Affiliation(s)
- Feng Gao
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
| | - Hao Wu
- b Department of Clinical Laboratory , Hebei Medical University , Shijiazhuang , China
| | - Rui Wang
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
| | - Yang Guo
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
| | - Zefeng Zhang
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
| | - Tao Wang
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
| | - Guoliang Zhang
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
| | - Changjiang Liu
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
| | - Junfeng Liu
- a Department of Thoracic Surgery , the Fourth Hospital of Hebei Medical University , Shijiazhuang , China
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Park JK, Kim KY, Sim YW, Kim YI, Kim JK, Lee C, Han J, Kim CU, Lee JE, Park S. Structures of three ependymin-related proteins suggest their function as a hydrophobic molecule binder. IUCRJ 2019; 6:729-739. [PMID: 31316816 PMCID: PMC6608618 DOI: 10.1107/s2052252519007668] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/27/2019] [Indexed: 06/10/2023]
Abstract
Ependymin was first discovered as a predominant protein in brain extracellular fluid in fish and was suggested to be involved in functions mostly related to learning and memory. Orthologous proteins to ependymin called ependymin-related proteins (EPDRs) have been found to exist in various tissues from sea urchins to humans, yet their functional role remains to be revealed. In this study, the structures of EPDR1 from frog, mouse and human were determined and analyzed. All of the EPDR1s fold into a dimer using a monomeric subunit that is mostly made up of two stacking antiparallel β-sheets with a curvature on one side, resulting in the formation of a deep hydrophobic pocket. All six of the cysteine residues in the monomeric subunit participate in the formation of three intramolecular disulfide bonds. Other interesting features of EPDR1 include two asparagine residues with glycosylation and a Ca2+-binding site. The EPDR1 fold is very similar to the folds of bacterial VioE and LolA/LolB, which also use a similar hydrophobic pocket for their respective functions as a hydrophobic substrate-binding enzyme and a lipoprotein carrier, respectively. A further fatty-acid binding assay using EPDR1 suggests that it indeed binds to fatty acids, presumably via this pocket. Additional interactome analysis of EPDR1 showed that EPDR1 interacts with insulin-like growth factor 2 receptor and flotillin proteins, which are known to be involved in protein and vesicle translocation.
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Affiliation(s)
- Jeong Kuk Park
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
| | - Keon Young Kim
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
| | - Yeo Won Sim
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
| | - Yong-In Kim
- Center for Bioanalysis, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
| | - Jin Kyun Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Cheol Lee
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jeongran Han
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Chae Un Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - J. Eugene Lee
- Center for Bioanalysis, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
| | - SangYoun Park
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
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Krogsaeter EK, Biel M, Wahl-Schott C, Grimm C. The protein interaction networks of mucolipins and two-pore channels. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:1111-1123. [PMID: 30395881 PMCID: PMC7111325 DOI: 10.1016/j.bbamcr.2018.10.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND The endolysosomal, non-selective cation channels, two-pore channels (TPCs) and mucolipins (TRPMLs), regulate intracellular membrane dynamics and autophagy. While partially compensatory for each other, isoform-specific intracellular distribution, cell-type expression patterns, and regulatory mechanisms suggest different channel isoforms confer distinct properties to the cell. SCOPE OF REVIEW Briefly, established TPC/TRPML functions and interaction partners ('interactomes') are discussed. Novel TRPML3 interactors are shown, and a meta-analysis of experimentally obtained channel interactomes conducted. Accordingly, interactomes are compared and contrasted, and subsequently described in detail for TPC1, TPC2, TRPML1, and TRPML3. MAJOR CONCLUSIONS TPC interactomes are well-defined, encompassing intracellular membrane organisation proteins. TRPML interactomes are varied, encompassing cardiac contractility- and chaperone-mediated autophagy proteins, alongside regulators of intercellular signalling. GENERAL SIGNIFICANCE Comprising recently proposed targets to treat cancers, infections, metabolic disease and neurodegeneration, the advancement of TPC/TRPML understanding is of considerable importance. This review proposes novel directions elucidating TPC/TRPML relevance in health and disease. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Einar K Krogsaeter
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Munich (LMU) Nussbaumstrasse 26, 80336 Munich
| | - Martin Biel
- Department of Pharmacy - Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Germany
| | - Christian Wahl-Schott
- Hannover Medical School, Institute for Neurophysiology, OE 4230, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Christian Grimm
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Munich (LMU) Nussbaumstrasse 26, 80336 Munich.
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Liu C, Shang Z, Ma Y, Ma J, Song J. HOTAIR/miR-214-3p/FLOT1 axis plays an essential role in the proliferation, migration, and invasion of hepatocellular carcinoma. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2019; 12:50-63. [PMID: 31933720 PMCID: PMC6944023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/07/2018] [Indexed: 06/10/2023]
Abstract
BACKGROUND Long non-coding RNA (lncRNA) Hox transcript antisense intergenic RNA (HOTAIR) has been reported to play an important role in hepatocellular carcinoma (HCC) progression. Although there is evidence on HOTAIR being associated with HCC progression, the underlying mechanism remains to be further clarified. METHODS HOTAIR, miR-214-3p and FLOT1 expression were measured by quantitative real-time PCR or western blot. Cell proliferation, migration, and invasion were displayed by transwell assay, MTT, and colony formation assay. The relationship between HOTAIR, miR-214-3p, and FLOT1 was investigated by luciferase reporter assay. Tumor suppressive effect of HOTAIR was displayed by HepG2 xenografting to nude mice. RESULTS HOTAIR and FLOT1 expression were significantly up-regulated, whereas miR-214-3p was obviously down-regulated. Also, down-regulation of HOTAIR and FLOT1 as well as up-regulation of miR-214-3p inhibited cell proliferation, invasion, and migration. Intriguingly, the effects of miR-214-3p overexpression on HCC cells were rescued by high expression of HOTAIR. Otherwise, HOTAIR regulated FLOT1 expression through targeting miR-214-3p in HCC cells. Simultaneously, low HOTAIR expression inhibited FLOT1 expression by up-regulating miR-214-3p, which suppressed tumor growth in vivo. CONCLUSION HOTAIR expression indirectly regulated FLOT1 expression through endogenous competition with miR-214-3p. HOTAIR/miR-214-3p/FLOT1 axis affected the cell proliferation, migration, and invasion of HCC.
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Affiliation(s)
- Chong Liu
- Department of General Surgery, Second Hospital of Shanxi Medical UniversityTaiyuan, Shanxi, China
| | - Zhonghua Shang
- Department of General Surgery, Second Hospital of Shanxi Medical UniversityTaiyuan, Shanxi, China
| | - Yu Ma
- Department of General Surgery, Tai Yuan City Central HospitalTaiyuan, Shanxi, China
| | - Jianfang Ma
- Department of General Surgery, Second Hospital of Shanxi Medical UniversityTaiyuan, Shanxi, China
| | - Jian Song
- Department of General Surgery, Second Hospital of Shanxi Medical UniversityTaiyuan, Shanxi, China
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Saal KA, Richter F, Rehling P, Rizzoli SO. Combined Use of Unnatural Amino Acids Enables Dual-Color Super-Resolution Imaging of Proteins via Click Chemistry. ACS NANO 2018; 12:12247-12254. [PMID: 30525434 DOI: 10.1021/acsnano.8b06047] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recent advances in optical nanoscopy have brought the imaging resolution to the size of the individual macromolecules, thereby setting stringent requirements for the fluorescent labels. Such requirements are optimally fulfilled by the incorporation of unnatural amino acids (UAAs) in the proteins of interest (POIs), followed by fluorophore conjugation via click chemistry. However, this approach has been limited to single POIs in mammalian cells. Here we solve this problem by incorporating different UAAs in different POIs, which are expressed in independent cell sets. The cells are then fused, thereby combining the different proteins and organelles, and are easily imaged by dual-color super-resolution microscopy. This procedure, which we termed Fuse2Click, is simple, requires only the well-established Amber codon, and allows the use of all previously optimized UAAs and tRNA/RS pairs. This should render it a tool of choice for multicolor click-based imaging.
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Affiliation(s)
- Kim-A Saal
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration , University Medical Center Göttingen, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain , Göttingen , Germany
| | - Frank Richter
- Institute for Cellular Biochemistry , University Medical Center Göttingen , Göttingen , Germany
| | - Peter Rehling
- Institute for Cellular Biochemistry , University Medical Center Göttingen , Göttingen , Germany
| | - Silvio O Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration , University Medical Center Göttingen, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain , Göttingen , Germany
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Breher-Esch S, Sahini N, Trincone A, Wallstab C, Borlak J. Genomics of lipid-laden human hepatocyte cultures enables drug target screening for the treatment of non-alcoholic fatty liver disease. BMC Med Genomics 2018; 11:111. [PMID: 30547786 PMCID: PMC6295111 DOI: 10.1186/s12920-018-0438-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/23/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is a major health burden in need for new medication. To identify potential drug targets a genomic study was performed in lipid-laden primary human hepatocyte (PHH) and human hepatoma cell cultures. METHODS PHH, HuH7 and HepG2 hepatoma cell cultures were treated with lipids and/or TNFα. Intracellular lipid load was quantified with the ORO assay. The Affymetrix HG-U133+ array system was employed to perform transcriptome analysis. The lipid droplet (LD) growth and fusion was determined by fluorescence microscopy. LD associated proteins were imaged by confocal immunofluorescence microscopy and confirmed by Western immunoblotting. Bioinformatics defined perturbed metabolic pathways. RESULTS Whole genome expression profiling identified 227, 1031 and 571 significant regulated genes. Likewise, the combined lipid and TNFα treatment of PHH, HuH7 and HepG2 cell cultures revealed 154, 1238 and 278 differentially expressed genes. Although genomic responses differed among in-vitro systems, commonalities were ascertained by filtering the data for LD associated gene regulations. Among others the LD-growth and fusion associated cell death inducing DFFA like effector C (CIDEC), perilipins (PLIN2, PLIN3), the synaptosome-associated-protein 23 and the vesicle associated membrane protein 3 were strongly up-regulated. Likewise, the PPAR targets pyruvate-dehydrogenase-kinase-4 and angiopoietin-like-4 were up-regulated as was hypoxia-inducible lipid droplet-associated (HILPDA), flotilin and FGF21. Their inhibition ameliorates triglyceride and cholesterol accumulation. TNFα treatment elicited strong induction of the chemokine CXCL8, the kinases MAP3K8, MAP4K4 and negative regulators of cytokine signaling, i.e. SOCS2&SOCS3. Live cell imaging of DsRED calreticulin plasmid transfected HuH7 cells permitted an assessment of LD growth and fusion and confocal immunofluorescence microscopy evidenced induced LD-associated PLIN2, CIDEC, HIF1α, HILPDA, JAK1, PDK4 and ROCK2 expression. Notwithstanding, CPT1A protein was repressed to protect mitochondria from lipid overload. Pharmacological inhibition of the GTPase-dynamin and the fatty acid transporter-2 reduced lipid uptake by 28.5 and 35%, respectively. Finally, a comparisons of in-vitro/NAFLD patient biopsy findings confirmed common gene regulations thus demonstrating clinical relevance. CONCLUSION The genomics of fat-laden hepatocytes revealed LD-associated gene regulations and perturbed metabolic pathways. Immunofluorescence microscopy confirmed expression of coded proteins to provide a rationale for therapeutic intervention strategies. Collectively, the in-vitro system permits testing of drug candidates.
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Affiliation(s)
- Stephanie Breher-Esch
- Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Nishika Sahini
- Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Anna Trincone
- Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Christin Wallstab
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Jürgen Borlak
- Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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Sandvig K, Kavaliauskiene S, Skotland T. Clathrin-independent endocytosis: an increasing degree of complexity. Histochem Cell Biol 2018; 150:107-118. [PMID: 29774430 PMCID: PMC6096564 DOI: 10.1007/s00418-018-1678-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2018] [Indexed: 11/03/2022]
Abstract
This article aims at providing an update on the complexity of clathrin-independent endocytosis. It is now almost 30 years since we first wrote a review about its existence; at that time many people believed that with the exception of macropinocytosis, which will only be briefly mentioned in this review, all uptake could be accounted for by clathrin-dependent endocytosis. Now it is generally accepted that there are different clathrin-independent mechanisms, some of them regulated by ligands and membrane lipid composition. They can be both dynamin-dependent and -independent, meaning that the uptake cannot be accounted for by caveolae and other dynamin-dependent processes such as tubular structures that can be induced by toxins, e.g. Shiga toxin, or the fast endophilin mediated endocytosis recently described. Caveolae seem to be mostly quite stable structures with other functions than endocytosis, but evidence suggests that they may have cell-type dependent functions. Although several groups have been working on endocytic mechanisms for years, and new advanced methods have improved our ability to study mechanistic details, there are still a number of important questions we need to address, such as: How many endocytic mechanisms does a cell have? How quantitatively important are they? What about the complexity in polarized cells where clathrin-independent endocytosis is differentially regulated on the apical and basolateral poles? These questions are not easy to answer since one and the same molecule may contribute to more than one process, and manipulating one mechanism can affect another. Also, several inhibitors of endocytic processes commonly used turn out to be less specific than originally thought. We will here describe the current view of clathrin-independent endocytic processes and the challenges in studying them.
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Affiliation(s)
- Kirsten Sandvig
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379, Oslo, Norway.
- Department of Molecular Biosciences, University of Oslo, 0316, Oslo, Norway.
| | - Simona Kavaliauskiene
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379, Oslo, Norway
| | - Tore Skotland
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379, Oslo, Norway
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Guo AY, Liang XJ, Liu RJ, Li XX, Bi W, Zhou LY, Tang CE, Yan A, Chen ZC, Zhang PF. Flotilin-1 promotes the tumorigenicity and progression of malignant phenotype in human lung adenocarcinoma. Cancer Biol Ther 2018; 18:715-722. [PMID: 28825855 DOI: 10.1080/15384047.2017.1360445] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Lung adenocarcinoma (LUAD) accounts for the most common histological subtype of lung cancer which remains the leading cause of cancer death worldwide. The discovery of more sensitive and specific novel target biomarkers for predicting the development and progression of LUAD is imperative. Flotillin-1 (Flot-1) has been reported to have important roles in the progression of several tumor types but not been reported in the progression of LUAD. Here, we demonstrated that the expression of flotillin-1 was upregulated in 5 LUAD cells. Moreover, multiple approaches were used to explore the tumorigenicity of flotillin-1 in LUAD cell lines. The expression levels of flotillin-1 were analyzed by immunoblotting after overexpression and siRNA-based knockdown. Cell proliferation, scratch wound healing, transwell migration and matrigel invasion and xenograft tumor growth assays were used to determine the role of flotillin-1 in LUAD progression. Downregulation of flotillin-1 reversed, whereas upregulation of flotillin-1 enhanced, the malignant phenotype of LUAD cells in vitro. Consistently, cells with flotillin-1 knockdown formed smaller tumors in nude mice than cells transfected with the empty vector. Furthermore, the control group demonstrated significantly more tumorigenic effects compared to the flotillin-1-silenced group in the xenograft model of LUAD. In all, there draws a conclusion that flotillin-1 is a tumorigenic protein that plays an important role in promoting the proliferation and tumorigenicity of LUAD, suggesting that flotillin-1 may represent a novel the therapeutic target to LUAD.
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Affiliation(s)
- Ai Yun Guo
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Xu Jun Liang
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Rui Jie Liu
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Xiao Xiao Li
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Wu Bi
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Liu Ying Zhou
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Can E Tang
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Ang Yan
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Zhu Chu Chen
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
| | - Peng Fei Zhang
- a Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University , Changsha , Hunan , China
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Flotillin proteins recruit sphingosine to membranes and maintain cellular sphingosine-1-phosphate levels. PLoS One 2018; 13:e0197401. [PMID: 29787576 PMCID: PMC5963794 DOI: 10.1371/journal.pone.0197401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 04/30/2018] [Indexed: 01/09/2023] Open
Abstract
Sphingosine-1-phosphate (S1P) is an important lipid signalling molecule. S1P is produced via intracellular phosphorylation of sphingosine (Sph). As a lipid with a single fatty alkyl chain, Sph may diffuse rapidly between cellular membranes and through the aqueous phase. Here, we show that the absence of microdomains generated by multimeric assemblies of flotillin proteins results in reduced S1P levels. Cellular phenotypes of flotillin knockout mice, including changes in histone acetylation and expression of Isg15, are recapitulated when S1P synthesis is perturbed. Flotillins bind to Sph in vitro and increase recruitment of Sph to membranes in cells. Ectopic re-localisation of flotillins within the cell causes concomitant redistribution of Sph. The data suggest that flotillins may directly or indirectly regulate cellular sphingolipid distribution and signalling.
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Flotillins Regulate Focal Adhesions by Interacting with α-Actinin and by Influencing the Activation of Focal Adhesion Kinase. Cells 2018; 7:cells7040028. [PMID: 29642469 PMCID: PMC5946105 DOI: 10.3390/cells7040028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 02/01/2023] Open
Abstract
Cell–matrix adhesion and cell migration are physiologically important processes that also play a major role in cancer spreading. In cultured cells, matrix adhesion depends on integrin-containing contacts such as focal adhesions. Flotillin-1 and flotillin-2 are frequently overexpressed in cancers and are associated with poor survival. Our previous studies have revealed a role for flotillin-2 in cell–matrix adhesion and in the regulation of the actin cytoskeleton. We here show that flotillins are important for cell migration in a wound healing assay and influence the morphology and dynamics of focal adhesions. Furthermore, anchorage-independent growth in soft agar is enhanced by flotillins. In the absence of flotillins, especially flotillin-2, phosphorylation of focal adhesion kinase and extracellularly regulated kinase is diminished. Flotillins interact with α-actinin, a major regulator of focal adhesion dynamics. These findings are important for understanding the molecular mechanisms of how flotillin overexpression in cancers may affect cell migration and, especially, enhance metastasis formation.
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Xu R, Song X, Su P, Pang Y, Li Q. Identification and characterization of the lamprey Flotillin-1 gene with a role in cell adhesion. FISH & SHELLFISH IMMUNOLOGY 2017; 71:286-294. [PMID: 28687359 DOI: 10.1016/j.fsi.2017.06.061] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 05/31/2017] [Accepted: 06/30/2017] [Indexed: 06/07/2023]
Abstract
Flotillin-1 is a kind of localize into specific cholesterol rich microdomains in cellular membranes and highly conserved lipid rafts marker protein widely distributed in animals and plants. It provides a platform for the reaction of many proteins in signal transduction, as scaffolding plays an important role in transmembrane signaling and cell adhesion. Here, Flotillin-1 protein from lamprey was identified and characterized (designated as L-Flotillin-1). After a partial cDNA sequence of L-Flotillin-1 was identified in a lamprey supraneural body cDNA library, the full-length cDNA was obtained using 3'- and 5'-rapid amplification of cDNA ends (RACE). L-Flotillin-1 encodes 424 amino acids and contains a prohibitin domain and a flotillin repetitive area. The L-Flotillin-1 protein was primarily distributed in kidney, supraneural body, gill, heart, liver and intestine via real-time PCR and immunohistochemistry assays. Immunofluorescence and western blot results showed that L-Flotillin-1 was considered to be used as a marker protein of lamprey lipid rafts and exosomes. Furthermore, overexpression of pEGFP-N1-L-Flotillin-1 induced the up-regulation of vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) mRNA levels. These results indicated that the L-Flotillin-1 gene encodes Flotillin-1 protein that was used as a conserved marker protein and may play an important role in cell adhesion, providing clues for understanding the universal functions of Flotillin-1 proteins in other species and suggesting that these proteins could serve as pattern recognition molecules in immunotherapy. We revealed that Flotillin-1 protein of lamprey overexpression in human cells plays a prevalent role in cell migration and provide new thought of treatment to diseases.
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Affiliation(s)
- Rong Xu
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian 116081, China
| | - Xiaoping Song
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian 116081, China; Affilated Zhongshan Hospital, Dalian University Respiratory Medicine, Dalian 116001, China
| | - Peng Su
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian 116081, China
| | - Yue Pang
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian 116081, China.
| | - Qingwei Li
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian 116081, China.
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Gazo I, Dietrich MA, Prulière G, Shaliutina-Kolešová A, Shaliutina O, Cosson J, Chenevert J. Protein phosphorylation in spermatozoa motility of Acipenser ruthenus and Cyprinus carpio. Reproduction 2017; 154:653-673. [PMID: 28851826 DOI: 10.1530/rep-16-0662] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 08/17/2017] [Accepted: 08/29/2017] [Indexed: 12/15/2022]
Abstract
Spermatozoa of externally fertilizing freshwater fish possess several different modes of motility activation. Spermatozoa of common carp (Cyprinus carpio L.) are activated by hypoosmolality, whereas spermatozoa of sterlet (Acipenser ruthenus) require Ca2+ and low concentration of K+ for motility activation. Intracellular signaling differs between these two species as well, particularly in terms of utilization of secondary messengers (cAMP and Ca2+), and kinase activities. The current study was performed in order to determine the importance of protein phosphorylation and protein kinases for activation of sperm motility in carp and sterlet. Treatment with kinase inhibitors indicates that protein kinases A and C (PKA and PKC) participate in spermatozoa motility of both species. Immunodetection of phospho-(Ser/Thr) PKA substrates shows that phosphorylated proteins are localized differently in spermatozoa of carp and sterlet. Strong phosphorylation of PKC substrate was observed in flagella of sterlet spermatozoa, whereas in carp sperm, PKC substrates were lightly phosphorylated in the midpiece and flagella. Motility activation induced either phosphorylation or dephosphorylation on serine, threonine and tyrosine residues of numerous proteins in carp and sterlet spermatozoa. Proteomic methods were used to identify proteins whose phosphorylation state changes upon the initiation of sperm motility. Numerous mitochondrial and glycolytic enzymes were identified in spermatozoa of both species, as well as axonemal proteins, heat shock proteins, septins and calcium-binding proteins. Our results contribute to an understanding of the roles of signaling molecules, protein kinases and protein phosphorylation in motility activation and regulation of two valuable fish species, C. carpio and A. ruthenus.
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Affiliation(s)
- Ievgeniia Gazo
- University of South Bohemia in Cˇeské Budeˇjovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Vodnˇany, Czech Republic
| | - Mariola A Dietrich
- Department of Gametes and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland
| | - Gérard Prulière
- Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer, Observatoire Océanologique, Villefranche sur-mer, France
| | - Anna Shaliutina-Kolešová
- University of South Bohemia in Cˇeské Budeˇjovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Vodnˇany, Czech Republic
| | - Olena Shaliutina
- University of South Bohemia in Cˇeské Budeˇjovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Vodnˇany, Czech Republic
| | - Jacky Cosson
- University of South Bohemia in Cˇeské Budeˇjovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Vodnˇany, Czech Republic
| | - Janet Chenevert
- Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer, Observatoire Océanologique, Villefranche sur-mer, France
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Stamatovic SM, Johnson AM, Sladojevic N, Keep RF, Andjelkovic AV. Endocytosis of tight junction proteins and the regulation of degradation and recycling. Ann N Y Acad Sci 2017; 1397:54-65. [PMID: 28415156 DOI: 10.1111/nyas.13346] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/31/2022]
Abstract
Internalization of tight junction (TJ) proteins from the plasma membrane is a pivotal mechanism regulating TJ plasticity and function in both epithelial and endothelial barrier tissues. Once internalized, the TJ proteins enter complex vesicular machinery, where further trafficking is directly dependent on the initiating stimulus and downstream signaling pathways that regulate the sorting and destiny of TJ proteins, as well as on cell and barrier responses. The destiny of internalized TJ proteins is recycling to the plasma membrane or sorting to late endosomes and degradation. This review highlights recent advances in our knowledge of endocytosis and vesicular trafficking of TJ proteins in both epithelial and endothelial cells. A greater understanding of these processes may allow for the development of methods to modulate barrier permeability for drug delivery or prevent barrier dysfunction in disease states.
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Affiliation(s)
| | | | | | - Richard F Keep
- Neurosurgery.,Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
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Plasmalogen biosynthesis is spatiotemporally regulated by sensing plasmalogens in the inner leaflet of plasma membranes. Sci Rep 2017; 7:43936. [PMID: 28272479 PMCID: PMC5341075 DOI: 10.1038/srep43936] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 01/31/2017] [Indexed: 12/14/2022] Open
Abstract
Alkenyl ether phospholipids are a major sub-class of ethanolamine- and choline-phospholipids in which a long chain fatty alcohol is attached at the sn-1 position through a vinyl ether bond. Biosynthesis of ethanolamine-containing alkenyl ether phospholipids, plasmalogens, is regulated by modulating the stability of fatty acyl-CoA reductase 1 (Far1) in a manner dependent on the level of cellular plasmalogens. However, precise molecular mechanisms underlying the regulation of plasmalogen synthesis remain poorly understood. Here we show that degradation of Far1 is accelerated by inhibiting dynamin-, Src kinase-, or flotillin-1-mediated endocytosis without increasing the cellular level of plasmalogens. By contrast, Far1 is stabilized by sequestering cholesterol with nystatin. Moreover, abrogation of the asymmetric distribution of plasmalogens in the plasma membrane by reducing the expression of CDC50A encoding a β-subunit of flippase elevates the expression level of Far1 and plasmalogen synthesis without reducing the total cellular level of plasmalogens. Together, these results support a model that plasmalogens localised in the inner leaflet of the plasma membranes are sensed for plasmalogen homeostasis in cells, thereby suggesting that plasmalogen synthesis is spatiotemporally regulated by monitoring cellular level of plasmalogens.
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36
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Luo Y, Akama T, Okayama A, Yoshihara A, Sue M, Oda K, Hayashi M, Ishido Y, Hirano H, Hiroi N, Katoh R, Suzuki K. A Novel Role for Flotillin-Containing Lipid Rafts in Negative-Feedback Regulation of Thyroid-Specific Gene Expression by Thyroglobulin. Thyroid 2016; 26:1630-1639. [PMID: 27676653 DOI: 10.1089/thy.2016.0187] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Thyroglobulin (Tg) stored in thyroid follicles regulates follicular function in thyroid hormone (TH) synthesis by suppressing thyroid-specific gene expression in a concentration-dependent manner. Thus, Tg is an intrinsic negative-feedback regulator that can restrain the effect of thyrotropin (TSH) in the follicle. However, the underlying mechanisms by which Tg exerts its prominent autoregulatory effect following recognition by thyrocytes remains unclear. METHODS In order to identify potential proteins that recognize and interact with Tg, mass spectrometry was used to analyze immunoprecipitated Tg-bound proteins derived from Tg-treated rat thyroid FRTL-5 cells. RESULTS Flotillin 1 and flotillin 2, two homologs that are integral membrane proteins in lipid rafts, were identified as novel Tg-binding proteins with high confidence. Further studies revealed that flotillins physically interact with endocytosed Tg, and together these proteins redistribute from the cell membrane to cytoplasmic vesicles. Treatment with the lipid raft disrupter methyl-β-cyclodextrin abolished both the endocytosis and the negative-feedback effect of Tg on thyroid-specific gene expression. Meanwhile, siRNA-mediated knockdown of flotillin 1 or flotillin 2 also significantly inhibited Tg effects on gene expression. CONCLUSION Together these results indicate that flotillin-containing lipid rafts are essential for follicular Tg to be recognized by thyrocytes and exert its negative-feedback effects in the thyroid.
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Affiliation(s)
- Yuqian Luo
- 1 Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University , Tokyo, Japan
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
- 3 Department of Pathology, Faculty of Medicine, University of Yamanashi , Yamanashi, Japan
| | - Takeshi Akama
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
| | - Akiko Okayama
- 4 Advanced Medical Research Center, Yokohama City University , Yokohama, Japan
| | - Aya Yoshihara
- 1 Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University , Tokyo, Japan
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
- 5 Department of Education Planning and Development, Faculty of Medicine, Toho University , Tokyo, Japan
| | - Mariko Sue
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
- 6 Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Toho University , Tokyo, Japan
| | - Kenzaburo Oda
- 1 Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University , Tokyo, Japan
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
- 6 Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Toho University , Tokyo, Japan
| | - Moyuru Hayashi
- 1 Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University , Tokyo, Japan
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
| | - Yuko Ishido
- 1 Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University , Tokyo, Japan
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
| | - Hisashi Hirano
- 3 Department of Pathology, Faculty of Medicine, University of Yamanashi , Yamanashi, Japan
| | - Naoki Hiroi
- 5 Department of Education Planning and Development, Faculty of Medicine, Toho University , Tokyo, Japan
| | - Ryohei Katoh
- 3 Department of Pathology, Faculty of Medicine, University of Yamanashi , Yamanashi, Japan
| | - Koichi Suzuki
- 1 Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University , Tokyo, Japan
- 2 Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases , Tokyo, Japan
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Upregulation of flotillin-1 promotes invasion and metastasis by activating TGF-β signaling in nasopharyngeal carcinoma. Oncotarget 2016; 7:4252-64. [PMID: 26646322 PMCID: PMC4826203 DOI: 10.18632/oncotarget.6483] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/25/2015] [Indexed: 12/14/2022] Open
Abstract
Metastasis is the main cause of cancer-related deaths. Nasopharyngeal carcinoma (NPC) is characterized by severe local invasion and high incidence of regional lymph node metastasis, which represents poor prognosis. However, the underlying mechanism that induces lymph node metastasis of NPC remains largely unknown. Herein, we report that flotillin-1 (FLOT1), a component of lipid raft, which was reported to be involved in tumor progression, was robustly upregulated in the NPC samples with lymph node metastasis. High FLOT1 expression was significantly associated with N classification as well as poorer overall and disease-free survivals in 169 archived clinical NPC samples. Overexpression of FLOT1 enhanced the migratory and invasive abilities of NPC cells in vitro, and more importantly, promoted invasion into the surrounding tissues and metastasis to lymph nodes in vivo. Whereas silencing of endogenous FLOT1 in NPC cells decreased the local invasion and metastasis to lymph nodes. Furthermore, FLOT1 induced the expression and secretion of TGF-β1, facilitated the activation of TGF-β/Smad3 signaling to effectuate epithelial-mesenchymal transition. Our findings present new evidence that FLOT1 plays an important role in promoting aggressive behavior of NPC and provide new insights into the regulatory mechanism of TGF-β signaling.
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Shi H, Guo G, Liu R, Wang C, Xu X, Ruan L. Membrane associated protein flotillin-2 in Litopenaeus vannamei plays a role in WSSV infection. FISH & SHELLFISH IMMUNOLOGY 2016; 54:247-253. [PMID: 27079424 DOI: 10.1016/j.fsi.2016.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/05/2016] [Accepted: 04/08/2016] [Indexed: 06/05/2023]
Abstract
Flotillin-2, an important protein of vesicular endocytosis, plays an essential role in a large number of cellular processes, including viruses and pathogen infection. In the present study, a flotillin-2 homolog in Litopenaeus vannamei, designed as Lvflotillin-2, was cloned and characterized. To analyze the putative role of Lvflotillin-2 during white spot syndrome virus (WSSV) infection, real-time quantitative PCR was performed. The result showed that the transcriptional level of Lvflotillin-2 was up-regulated significantly after virus challenge. Furthermore, upon WSSV stimulation, Lvflotillin-2 in shrimp cells could translocate from the plasma membrane to intracellular compartments, and unexpectedly, also into nucleus. Additionally, depletion of Lvflotillin-2 inhibited WSSV gene ie1 transcription. It suggested that Lvflotillin-2 could be hijacked by WSSV. These observations indicated that Lvflotillin-2 was involved in WSSV infection, and presented here should be useful for gaining insight into shrimp immunity and WSSV pathogenesis.
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Affiliation(s)
- Hong Shi
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of State Oceanic Administration, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province, South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Xiamen, 361005, PR China
| | - Guangran Guo
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of State Oceanic Administration, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province, South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Xiamen, 361005, PR China; School of Life Science, Xiamen University, Xiamen, 361005, PR China
| | - Rongdiao Liu
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of State Oceanic Administration, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province, South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Xiamen, 361005, PR China; School of Life Science, Xiamen University, Xiamen, 361005, PR China
| | - Chuanqi Wang
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of State Oceanic Administration, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province, South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Xiamen, 361005, PR China; School of Life Science, Xiamen University, Xiamen, 361005, PR China
| | - Xun Xu
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of State Oceanic Administration, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province, South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Xiamen, 361005, PR China; School of Life Science, Xiamen University, Xiamen, 361005, PR China
| | - Lingwei Ruan
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of State Oceanic Administration, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province, South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Xiamen, 361005, PR China.
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Elkin SR, Bendris N, Reis CR, Zhou Y, Xie Y, Huffman KE, Minna JD, Schmid SL. A systematic analysis reveals heterogeneous changes in the endocytic activities of cancer cells. Cancer Res 2015; 75:4640-50. [PMID: 26359453 DOI: 10.1158/0008-5472.can-15-0939] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/22/2015] [Indexed: 11/16/2022]
Abstract
Metastasis is a multistep process requiring cancer cell signaling, invasion, migration, survival, and proliferation. These processes require dynamic modulation of cell surface proteins by endocytosis. Given this functional connection, it has been suggested that endocytosis is dysregulated in cancer. To test this, we developed In-Cell ELISA assays to measure three different endocytic pathways: clathrin-mediated endocytosis, caveolae-mediated endocytosis, and clathrin-independent endocytosis and compared these activities using two different syngeneic models for normal and oncogene-transformed human lung epithelial cells. We found that all endocytic activities were reduced in the transformed versus normal counterparts. However, when we screened 29 independently isolated non-small cell lung cancer (NSCLC) cell lines to determine whether these changes were systematic, we observed significant heterogeneity. Nonetheless, using hierarchical clustering based on their combined endocytic properties, we identified two phenotypically distinct clusters of NSCLCs. One co-clustered with mutations in KRAS, a mesenchymal phenotype, increased invasion through collagen and decreased growth in soft agar, whereas the second was enriched in cells with an epithelial phenotype. Interestingly, the two clusters also differed significantly in clathrin-independent internalization and surface expression of CD44 and CD59. Taken together, our results suggest that endocytotic alterations in cancer cells that affect cell surface expression of critical molecules have a significant influence on cancer-relevant phenotypes, with potential implications for interventions to control cancer by modulating endocytic dynamics.
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Affiliation(s)
- Sarah R Elkin
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas
| | - Nawal Bendris
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas
| | - Carlos R Reis
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas
| | - Yunyun Zhou
- Department of Clinical Science and Quantitative Biomedical Research Center (QBRC), UT Southwestern Medical Center, Dallas, Texas
| | - Yang Xie
- Department of Clinical Science and Quantitative Biomedical Research Center (QBRC), UT Southwestern Medical Center, Dallas, Texas
| | - Kenneth E Huffman
- The Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, Texas
| | - John D Minna
- The Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, Texas. Departments of Internal Medicine and Pharmacology, UT Southwestern Medical Center, Dallas, Texas
| | - Sandra L Schmid
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas.
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Dubois L, Ronquist KKG, Ek B, Ronquist G, Larsson A. Proteomic Profiling of Detergent Resistant Membranes (Lipid Rafts) of Prostasomes. Mol Cell Proteomics 2015; 14:3015-22. [PMID: 26272980 DOI: 10.1074/mcp.m114.047530] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Indexed: 01/11/2023] Open
Abstract
Prostasomes are exosomes derived from prostate epithelial cells through exocytosis by multivesicular bodies. Prostasomes have a bilayered membrane and readily interact with sperm. The membrane lipid composition is unusual with a high contribution of sphingomyelin at the expense of phosphatidylcholine and saturated and monounsaturated fatty acids are dominant. Lipid rafts are liquid-ordered domains that are more tightly packed than the surrounding nonraft phase of the bilayer. Lipid rafts are proposed to be highly dynamic, submicroscopic assemblies that float freely within the liquid disordered membrane bilayer and some proteins preferentially partition into the ordered raft domains. We asked the question whether lipid rafts do exist in prostasomes and, if so, which proteins might be associated with them. Prostasomes of density range 1.13-1.19g/ml were subjected to density gradient ultracentrifugation in sucrose fabricated by phosphate buffered saline (PBS) containing 1% Triton X-100 with capacity for banding at 1.10 g/ml, i.e. the classical density of lipid rafts. Prepared prostasomal lipid rafts (by gradient ultracentrifugation) were analyzed by mass spectrometry. The clearly visible band on top of 1.10g/ml sucrose in the Triton X-100 containing gradient was subjected to liquid chromatography-tandem MS and more than 370 lipid raft associated proteins were identified. Several of them were involved in intraluminal vesicle formation, e.g. tetraspanins, ESCRTs, and Ras-related proteins. This is the first comprehensive liquid chromatography-tandem MS profiling of proteins in lipid rafts derived from exosomes. Data are available via ProteomeXchange with identifier PXD002163.
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Affiliation(s)
- Louise Dubois
- From the ‡Department of Medical Sciences, Uppsala University, 75185 Uppsala, Sweden
| | - Karl K Göran Ronquist
- From the ‡Department of Medical Sciences, Uppsala University, 75185 Uppsala, Sweden;
| | - Bo Ek
- §Department of Analytical Chemistry, Science for Life Laboratory, Uppsala University, 751 24 Uppsala, Sweden
| | - Gunnar Ronquist
- From the ‡Department of Medical Sciences, Uppsala University, 75185 Uppsala, Sweden
| | - Anders Larsson
- From the ‡Department of Medical Sciences, Uppsala University, 75185 Uppsala, Sweden
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Chen F, Bo J, Ma X, Dong L, Shan Z, Cui Q, Chen H, Wang K. A New Membrane Lipid Raft Gene SpFLT-1 Facilitating the Endocytosis of Vibrio alginolyticus in the Crab Scylla paramamosain. PLoS One 2015; 10:e0133443. [PMID: 26186350 PMCID: PMC4506021 DOI: 10.1371/journal.pone.0133443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 06/26/2015] [Indexed: 11/23/2022] Open
Abstract
Pathogens can enter their host cells by way of endocytosis in which the membrane lipid raft gene flotillins are probably involved in the invasion process and this is an important way to cause infection. In this study, a new gene SpFLT-1 was identified in Scylla paramamosain, which shared high identity with the flotillin-1 of other species. The SpFLT-1 gene was widely distributed in tissues and showed the highest level of mRNA transcripts in the hemocytes. This gene might be a maternal gene based on the evident results that it was highly expressed in maternal ovaries and in the early developmental stages of the zygote and early embryo stage whereas it gradually decreased in zoea 1. SpFLT-1 positively responded to the challenge of Vibrio alginolyticus with a significantly increased level of mRNA expression in the hemocytes and gills at 3 hours post infection (hpi). The SpFLT-1 protein was detected densely in the same fraction layer where the Vibrio protein was most present in the hemocytes and gills at 3 hpi. Furthermore, it was found that the expression of SpFLT-1 decreased to the base level following disappearance of the Vibrio protein at 6 hpi in the gills. Silencing SpFLT-1 inhibited the endocytosis rate of V. alginolyticus but overexpression of the gene could facilitate bacterial entry into the epithelioma papulosum cyprinid cells. Our study indicated that SpFLT-1 may act as a key protein involved in the process of bacterial infection and this sheds light on clarifying the pathogenesis of pathogens infecting S. paramamosain.
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Affiliation(s)
- Fangyi Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen, Fujian, P. R. China
| | - Jun Bo
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
| | - Xiaowan Ma
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen, Fujian, P. R. China
| | - Lixia Dong
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen, Fujian, P. R. China
| | - Zhongguo Shan
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen, Fujian, P. R. China
| | - Qian Cui
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen, Fujian, P. R. China
| | - Huiyun Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen, Fujian, P. R. China
| | - Kejian Wang
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, Fujian, P. R. China
- Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen, Fujian, P. R. China
- * E-mail:
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Jang D, Kwon H, Jeong K, Lee J, Pak Y. Essential role of flotillin-1 palmitoylation in the intracellular localization and signaling function of IGF-1 receptor. J Cell Sci 2015; 128:2179-90. [PMID: 25908865 DOI: 10.1242/jcs.169409] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/14/2015] [Indexed: 12/21/2022] Open
Abstract
Here, we explored flotillin-1-mediated regulation of insulin-like growth factor-1 (IGF-1) signaling. Flotillin-1-deficient cells exhibited a reduction in the activation of IGF-1 receptor (IGF-1R), ERK1/2 and Akt pathways, and the transcriptional activation of Elk-1 and the proliferation in response to IGF-1 were reduced in these cells. We found that IGF-1-independent flotillin-1 palmitoylation at Cys34 in the endoplasmic reticulum (ER) was required for the ER exit and the plasma membrane localization of flotillin-1 and IGF-1R. IGF-1-dependent depalmitoylation and repalmitoylation of flotillin-1 sustained tyrosine kinase activation of the plasma-membrane-targeted IGF-1R. Dysfunction and blocking the turnover of flotillin-1 palmitoylation abrogated cancer cell proliferation after IGF-1R signaling activation. Our data show that flotillin-1 palmitoylation is a new mechanism by which the intracellular localization and activation of IGF-1R are controlled.
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Affiliation(s)
- Donghwan Jang
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Korea
| | - Hayeong Kwon
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Korea
| | - Kyuho Jeong
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Korea
| | - Jaewoong Lee
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Korea
| | - Yunbae Pak
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Korea
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Yang FQ, Zhang HM, Chen SJ, Yan Y, Zheng JH. MiR-506 is down-regulated in clear cell renal cell carcinoma and inhibits cell growth and metastasis via targeting FLOT1. PLoS One 2015; 10:e0120258. [PMID: 25793370 PMCID: PMC4368579 DOI: 10.1371/journal.pone.0120258] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 01/21/2015] [Indexed: 01/01/2023] Open
Abstract
Background Some microRNAs (miRNAs) are abnormally expressed in cancer and contribute to tumorigenesis. In the present study, we investigated the role of miR-506 in clear cell renal cell carcinoma (ccRCC). Methods miR-506 expression was detected in renal cancer cell lines 786-O, ACHN, Caki-1, and Caki-2 and ccRCC specimens by quantitative real-time-PCR. We assessed the association of miR-506 expression with pathology and prognosis in ccRCC patients. We over-expressed and knocked-down miR-506 expression in two renal cancer cell lines, 786-O and ACHN, and assessed the impact on cell proliferation, migration and invasion. A luciferase reporter assay was conducted to confirm the target gene of miR-506 in renal cancer cell lines. Results miR-506 was significantly down-regulated in renal cancer cell lines and ccRCC specimens. Low miR-506 expression in ccRCC specimens was associated with an advanced clinical stage and poor prognosis. miR-506 expression was an independent prognostic marker of overall ccRCC patient survival in a multivariate analysis. Over-expression of miR-506 in renal cancer cells decreased cell growth and metastasis, In contrast, down-regulation of miR-506 expression promoted renal cancer cell growth and metastasis. FLOT1, a potential target gene of miR-506, was inversely correlated with miR-506 expression in ccRCC tissues. Consistent with the effect of miR-506, knockdown of FLOT1 by siRNA inhibited cell malignant behaviors. Rescue of FLOT1 expression partially restored the effects of miR-506. Conclusions miR-506 exerts its anti-cancer function by directly targeting FLOT1 in renal cancer, indicating a potential novel therapeutic role in renal cancer treatment.
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Affiliation(s)
- Feng-qiang Yang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Hai-ming Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Shao-Jun Chen
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Yang Yan
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Jun-hua Zheng
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
- * E-mail:
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Bodin S, Planchon D, Rios Morris E, Comunale F, Gauthier-Rouvière C. Flotillins in intercellular adhesion - from cellular physiology to human diseases. J Cell Sci 2014; 127:5139-47. [PMID: 25413346 DOI: 10.1242/jcs.159764] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Flotillin 1 and 2 are ubiquitous and highly conserved proteins. They were initially discovered in 1997 as being associated with specific caveolin-independent cholesterol- and glycosphingolipid-enriched membrane microdomains and as being expressed during axon regeneration. Flotillins have a role in a large number of physiopathological processes, mainly through their function in membrane receptor clustering and in the regulation of clathrin-independent endocytosis. In this Commentary, we summarize the research performed so far on the role of flotillins in cell-cell adhesion. Recent studies have demonstrated that flotillins directly regulate the formation of cadherin complexes. Indeed, flotillin microdomains are required for the dynamic association and stabilization of cadherins at cell-cell junctions and also for cadherin signaling. Moreover, because flotillins regulate endocytosis and also the actin cytoskeleton, they could have an indirect role in the assembly and stabilization of cadherin complexes. Because it has also recently been shown that flotillins are overexpressed during neurodegenerative diseases and in human cancers, where their upregulation is associated with metastasis formation and poor prognosis, understanding to what extent flotillin upregulation participates in the development of such pathologies is thus of particular interest, as well as how, at the molecular level, it might affect cell adhesion processes.
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Affiliation(s)
- Stéphane Bodin
- Equipe Labellisée Ligue Contre le Cancer, Universités Montpellier 2 et 1, CRBM, CNRS, UMR 5237, 1919 Route de Mende, 34293 Montpellier, France
| | - Damien Planchon
- Equipe Labellisée Ligue Contre le Cancer, Universités Montpellier 2 et 1, CRBM, CNRS, UMR 5237, 1919 Route de Mende, 34293 Montpellier, France
| | - Eduardo Rios Morris
- Equipe Labellisée Ligue Contre le Cancer, Universités Montpellier 2 et 1, CRBM, CNRS, UMR 5237, 1919 Route de Mende, 34293 Montpellier, France
| | - Franck Comunale
- Equipe Labellisée Ligue Contre le Cancer, Universités Montpellier 2 et 1, CRBM, CNRS, UMR 5237, 1919 Route de Mende, 34293 Montpellier, France
| | - Cécile Gauthier-Rouvière
- Equipe Labellisée Ligue Contre le Cancer, Universités Montpellier 2 et 1, CRBM, CNRS, UMR 5237, 1919 Route de Mende, 34293 Montpellier, France
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Saka SK, Honigmann A, Eggeling C, Hell SW, Lang T, Rizzoli SO. Multi-protein assemblies underlie the mesoscale organization of the plasma membrane. Nat Commun 2014; 5:4509. [PMID: 25060237 PMCID: PMC4124874 DOI: 10.1038/ncomms5509] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 06/25/2014] [Indexed: 02/07/2023] Open
Abstract
Most proteins have uneven distributions in the plasma membrane. Broadly speaking, this may be caused by mechanisms specific to each protein, or may be a consequence of a general pattern that affects the distribution of all membrane proteins. The latter hypothesis has been difficult to test in the past. Here, we introduce several approaches based on click chemistry, through which we study the distribution of membrane proteins in living cells, as well as in membrane sheets. We found that the plasma membrane proteins form multi-protein assemblies that are long lived (minutes), and in which protein diffusion is restricted. The formation of the assemblies is dependent on cholesterol. They are separated and anchored by the actin cytoskeleton. Specific proteins are preferentially located in different regions of the assemblies, from their cores to their edges. We conclude that the assemblies constitute a basic mesoscale feature of the membrane, which affects the patterning of most membrane proteins, and possibly also their activity. Although many proteins adopt uneven distributions in the plasma membrane, it is not clear how these nanoscale heterogeneities relate to the general protein patterning of the membrane. Saka et al. use click chemistry to reveal the mesoscale organization of membrane proteins into multi-protein assemblies.
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Affiliation(s)
- Sinem K Saka
- 1] Department of Neuro- and Sensory Physiology, University of Göttingen Medical Centre, and Centre for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany [2] International Max Planck Research School Molecular Biology, 37077 Göttingen, Germany
| | - Alf Honigmann
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford OX3 9DS, UK
| | - Stefan W Hell
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Thorsten Lang
- Department of Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, 53115 Bonn, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Centre, and Centre for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
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Meister M, Tikkanen R. Endocytic trafficking of membrane-bound cargo: a flotillin point of view. MEMBRANES 2014; 4:356-71. [PMID: 25019426 PMCID: PMC4194039 DOI: 10.3390/membranes4030356] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 06/28/2014] [Accepted: 07/02/2014] [Indexed: 12/03/2022]
Abstract
The ubiquitous and highly conserved flotillin proteins, flotillin-1 and flotillin-2, have been shown to be involved in various cellular processes such as cell adhesion, signal transduction through receptor tyrosine kinases as well as in cellular trafficking pathways. Due to the fact that flotillins are acylated and form hetero-oligomers, they constitutively associate with cholesterol-enriched lipid microdomains. In recent years, such microdomains have been appreciated as platforms that participate in endocytosis and other cellular trafficking steps. This review summarizes the current findings on the role of flotillins in membrane-bound cargo endocytosis and endosomal trafficking events. We will discuss the proposed function of flotillins in endocytosis in the light of recent findings that point towards a role for flotillins in a step that precedes the actual endocytic uptake of cargo molecules. Recent findings have also revealed that flotillins may be important for endosomal sorting and recycling of specific cargo molecules. In addition to these aspects, the cellular trafficking pathway of flotillins themselves as potential cargo in the context of growth factor signaling will be discussed.
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Affiliation(s)
- Melanie Meister
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany.
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany.
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Ogura M, Yamaki J, Homma MK, Homma Y. Phosphorylation of flotillin-1 by mitochondrial c-Src is required to prevent the production of reactive oxygen species. FEBS Lett 2014; 588:2837-43. [PMID: 24983503 DOI: 10.1016/j.febslet.2014.06.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 06/18/2014] [Indexed: 10/25/2022]
Abstract
We have shown that mitochondrial c-Src regulates reactive oxygen species (ROS) production by phosphorylating the succinate dehydrogenase A of respiratory complex II (CxII). To elucidate the molecular mechanisms underlying ROS production regulated by c-Src in the CxII, we investigated the CxII protein complex derived from cells treated with Src family kinase inhibitor PP2. We identified flotillin-1 as a c-Src target that prevents ROS production from CxII. Phosphorylation-site analysis suggests Tyr56 and Tyr149 on flotillin-1 as sites for phosphorylation by c-Src. A comparison of cells expressing flotillin-1 and its phosphorylation defective mutants confirms the requirement for flotillin-1 phosphorylation for its interaction with CxII and subsequent reduction in ROS production. Our findings suggest a critical role of flotillin-1 in ROS production mediated by c-Src.
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Affiliation(s)
- Masato Ogura
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Junko Yamaki
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Miwako K Homma
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Yoshimi Homma
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan.
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Zhang Y, Li J, Song Y, Chen F, Pei Y, Yao F. Flotillin-1 expression in human clear-cell renal cell carcinoma is associated with cancer progression and poor patient survival. Mol Med Rep 2014; 10:860-6. [PMID: 24913320 DOI: 10.3892/mmr.2014.2310] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 05/19/2014] [Indexed: 11/06/2022] Open
Abstract
The present study was designed to elucidate the expression levels and the proliferative effect of flotillin-1, an integral membrane protein encoded by the FLOT1 gene, in human clear-cell renal cell carcinoma (RCC). Flotillin has been implicated in other types of cancer, but the role of flotillin in RCC has not been established. Immunohistochemistry and western blotting were used to determine FLOT1 protein expression levels in RCC samples from 182 patients who underwent nephrectomy. FLOT1 mRNA expression levels were analyzed using reverse-transcription (RT) and RT-quantitative polymerase chain reaction (PCR). The association between FLOT1 expression levels in the tumor samples and patient survival time was examined using Kaplan‑Meier analysis. To demonstrate the proliferative effect of FLOT1 on RCC cells, a FLOT1 vector was transfected into four RCC cell lines and FLOT1 expression was inhibited using small interfering RNA. The proliferative ability of the RCC cells was investigated using a WST-1 assay and xenograft experiments with BALB/C nude mice. The results demonstrated that FLOT1 expression levels were significantly higher in RCC cell samples from patients than in healthy renal tissue, and the expression levels were associated with tumor stage, size and histological grade. In addition, FLOT1 significantly enhanced the proliferation of RCC cell lines in vitro and in vivo. These findings suggest that FLOT1, which is upregulated in RCC, is involved in RCC cell proliferation, tumorigenesis and progression. Therefore, FLOT1 is an independent prognostic marker and therapeutic target for patients with clear-cell RCC.
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Affiliation(s)
- Yiyan Zhang
- Department of Nephrology, First Affiliated Hospital of Chinese PLA General Hospital, Beijing 100048, P.R. China
| | - Jijun Li
- Department of Nephrology, First Affiliated Hospital of Chinese PLA General Hospital, Beijing 100048, P.R. China
| | - Yan Song
- Department of Nephrology, First Affiliated Hospital of Chinese PLA General Hospital, Beijing 100048, P.R. China
| | - Fengkun Chen
- Department of Nephrology, First Affiliated Hospital of Chinese PLA General Hospital, Beijing 100048, P.R. China
| | - Yin Pei
- Department of Nephrology, First Affiliated Hospital of Chinese PLA General Hospital, Beijing 100048, P.R. China
| | - Fenghua Yao
- Department of Nephrology, First Affiliated Hospital of Chinese PLA General Hospital, Beijing 100048, P.R. China
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Abstract
There are many pathways of endocytosis at the cell surface that apparently operate at the same time. With the advent of new molecular genetic and imaging tools, an understanding of the different ways by which a cell may endocytose cargo is increasing by leaps and bounds. In this review we explore pathways of endocytosis that occur in the absence of clathrin. These are referred to as clathrin-independent endocytosis (CIE). Here we primarily focus on those pathways that function at the small scale in which some have distinct coats (caveolae) and others function in the absence of specific coated intermediates. We follow the trafficking itineraries of the material endocytosed by these pathways and finally discuss the functional roles that these pathways play in cell and tissue physiology. It is likely that these pathways will play key roles in the regulation of plasma membrane area and tension and also control the availability of membrane during cell migration.
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Affiliation(s)
- Satyajit Mayor
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, and Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
| | - Robert G Parton
- The University of Queensland, Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, Queensland 4072, Brisbane, Australia
| | - Julie G Donaldson
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
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Guan Y, Song H, Zhang G, Ai X. Overexpression of flotillin-1 is involved in proliferation and recurrence of bladder transitional cell carcinoma. Oncol Rep 2014; 32:748-54. [PMID: 24890092 DOI: 10.3892/or.2014.3221] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/02/2014] [Indexed: 11/06/2022] Open
Abstract
Flotillin-1 (FLOT1) is known to have a role in tumorigenesis; however, the effect of FLOT1 on proliferation and recurrence of human transitional cell carcinoma (TCC) is unclear. Samples from 156 TCC patients and 142 patients undergoing open bladder surgery for indications other than TCC were used in the present study. FLOT1 protein expression was determined by immunohistochemistry and western blot analysis, and mRNA expression was detected by RT-PCR and real-time PCR. A FLOT1-expressing pcDEF3 vector was stably transfected into 4 TCC cell lines and FLOT1 expression was decreased by RNAi. Proliferative analysis of TCC cells was detected by the WST-1 assay and a xenograft model using BALB/C nude mice. The association between FLOT1 expression and TCC recurrence was also analyzed by adhesion, migration and invasion assays. FLOT1 expression in TCC was significantly overexpressed compared to normal urothelial tissue, and the level of FLOT1 expression was significantly correlated with tumor size, pathologic grade, clinical stage and recurrence. In addition, FLOT1 significantly increased the proliferative ability of TCC cells in vitro and in vivo. TCC cells with a high level of FLOT1 expression exhibited a higher level of adhesion, migration and invasion. FLOT1 expression was shown to be upregulated in human TCC. These findings suggest that FLOT1 plays an important role in the proliferation and recurrence of TCC and that silencing FLOT1 expression might be a novel therapeutic strategy.
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Affiliation(s)
- Yawei Guan
- Department of Urinary Surgery, Beijing Military Region General Hospital, Beijing 100700, P.R. China
| | - Haiyan Song
- Department of Blood Transfusion, The 309th Hospital of Chinese PLA, Beijing 100091, P.R. China
| | - Guohui Zhang
- Department of Urinary Surgery, Beijing Military Region General Hospital, Beijing 100700, P.R. China
| | - Xing Ai
- Department of Urinary Surgery, Beijing Military Region General Hospital, Beijing 100700, P.R. China
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