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The zinc-finger bearing xenogeneic silencer MucR in α-proteobacteria balances adaptation and regulatory integrity. THE ISME JOURNAL 2022; 16:738-749. [PMID: 34584215 PMCID: PMC8857273 DOI: 10.1038/s41396-021-01118-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/07/2021] [Accepted: 09/10/2021] [Indexed: 02/08/2023]
Abstract
Foreign AT-rich genes drive bacterial adaptation to new niches while challenging the existing regulation network. Here we report that MucR, a conserved regulator in α-proteobacteria, balances adaptation and regulatory integrity in Sinorhizobium fredii, a facultative microsymbiont of legumes. Chromatin immunoprecipitation sequencing coupled with transcriptomic data reveal that average transcription levels of both target and non-target genes, under free-living and symbiotic conditions, increase with their conservation levels. Targets involved in environmental adaptation and symbiosis belong to genus or species core and can be repressed or activated by MucR in a condition-dependent manner, implying regulatory integrations. However, most targets are enriched in strain-specific genes of lower expression levels and higher AT%. Within each conservation levels, targets have higher AT% and average transcription levels than non-target genes and can be further up-regulated in the mucR mutant. This is consistent with higher AT% of spacers between -35 and -10 elements of promoters for target genes, which enhances transcription. The MucR recruitment level linearly increases with AT% and the number of a flexible pattern (with periodic repeats of Ts) of target sequences. Collectively, MucR directly represses AT-rich foreign genes with predisposed high transcription potential while progressive erosions of its target sites facilitate regulatory integrations of foreign genes.
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2
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Diversity and distribution of viruses inhabiting the deepest ocean on Earth. THE ISME JOURNAL 2021; 15:3094-3110. [PMID: 33972725 PMCID: PMC8443753 DOI: 10.1038/s41396-021-00994-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/08/2021] [Accepted: 04/20/2021] [Indexed: 02/01/2023]
Abstract
As the most abundant biological entities on the planet, viruses significantly influence the overall functioning of marine ecosystems. The abundance, distribution, and biodiversity of viral communities in the upper ocean have been relatively well studied, but our understanding of viruses in the hadal biosphere remains poor. Here, we established the oceanic trench viral genome dataset (OTVGD) by analysing 19 microbial metagenomes derived from seawater and sediment samples of the Mariana, Yap, and Kermadec Trenches. The trench viral communities harbored remarkably high novelty, and they were predicted to infect ecologically important microbial clades, including Thaumarchaeota and Oleibacter. Significant inter-trench and intra-trench exchange of viral communities was proposed. Moreover, viral communities in different habitats (seawater/sediment and depth-stratified ocean zones) exhibited distinct niche-dependent distribution patterns and genomic properties. Notably, microbes and viruses in the hadopelagic seawater seemed to preferably adopt lysogenic lifestyles compared to those in the upper ocean. Furthermore, niche-specific auxiliary metabolic genes were identified in the hadal viral genomes, and a novel viral D-amino acid oxidase was functionally and phylogenetically characterized, suggesting the contribution of these genes in the utilization of refractory organic matter. Together, these findings highlight the genomic novelty, dynamic movement, and environment-driven diversification of viral communities in oceanic trenches, and suggest that viruses may influence the hadal ecosystem by reprogramming the metabolism of their hosts and modulating the community of keystone microbes.
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3
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Interaction dynamics and virus-host range for estuarine actinophages captured by epicPCR. Nat Microbiol 2021; 6:630-642. [PMID: 33633401 DOI: 10.1038/s41564-021-00873-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 01/28/2021] [Indexed: 01/31/2023]
Abstract
Viruses impact microbial diversity, gene flow and function through virus-host interactions. Although metagenomics surveys are rapidly cataloguing viral diversity, methods are needed to capture specific virus-host interactions in situ. Here, we leveraged metagenomics and repurposed emulsion paired isolation-concatenation PCR (epicPCR) to investigate viral diversity and virus-host interactions in situ over time in an estuarine environment. The method fuses a phage marker, the ribonucleotide reductase gene, with the host 16S rRNA gene of infected bacterial cells within emulsion droplets providing single-cell resolution for dozens of samples. EpicPCR captured in situ virus-host interactions for viral clades with no closely related database representatives. Abundant freshwater Actinobacteria lineages, in particular Rhodoluna sp., were the most common hosts for these poorly characterized viruses, with interactions correlated with environmental factors. Multiple methods used to identify virus-host interactions, including epicPCR, identified different and largely non-overlapping interactions within the vast virus-host interaction space. Tracking virus-host interaction dynamics also revealed that multi-host viruses had significantly longer periods with observed virus-host interactions, whereas single-host viruses were observed interacting with hosts at lower minimum abundances, suggesting more efficient interactions. Capturing in situ interactions with epicPCR revealed environmental and ecological factors shaping virus-host interactions, highlighting epicPCR as a valuable technique in viral ecology.
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4
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Burns R, Mandáková T, Gunis J, Soto-Jiménez LM, Liu C, Lysak MA, Novikova PY, Nordborg M. Gradual evolution of allopolyploidy in Arabidopsis suecica. Nat Ecol Evol 2021; 5:1367-1381. [PMID: 34413506 PMCID: PMC8484011 DOI: 10.1038/s41559-021-01525-w] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 07/01/2021] [Indexed: 02/06/2023]
Abstract
Most diploid organisms have polyploid ancestors. The evolutionary process of polyploidization is poorly understood but has frequently been conjectured to involve some form of 'genome shock', such as genome reorganization and subgenome expression dominance. Here we study polyploidization in Arabidopsis suecica, a post-glacial allopolyploid species formed via hybridization of Arabidopsis thaliana and Arabidopsis arenosa. We generated a chromosome-level genome assembly of A. suecica and complemented it with polymorphism and transcriptome data from all species. Despite a divergence around 6 million years ago (Ma) between the ancestral species and differences in their genome composition, we see no evidence of a genome shock: the A. suecica genome is colinear with the ancestral genomes; there is no subgenome dominance in expression; and transposon dynamics appear stable. However, we find changes suggesting gradual adaptation to polyploidy. In particular, the A. thaliana subgenome shows upregulation of meiosis-related genes, possibly to prevent aneuploidy and undesirable homeologous exchanges that are observed in synthetic A. suecica, and the A. arenosa subgenome shows upregulation of cyto-nuclear processes, possibly in response to the new cytoplasmic environment of A. suecica, with plastids maternally inherited from A. thaliana. These changes are not seen in synthetic hybrids, and thus are likely to represent subsequent evolution.
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Affiliation(s)
- Robin Burns
- grid.24194.3a0000 0000 9669 8503Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Terezie Mandáková
- grid.10267.320000 0001 2194 0956CEITEC - Central European Institute of Technology, and Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Joanna Gunis
- grid.24194.3a0000 0000 9669 8503Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Luz Mayela Soto-Jiménez
- grid.24194.3a0000 0000 9669 8503Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Chang Liu
- grid.9464.f0000 0001 2290 1502Institute of Biology, University of Hohenheim, Stuttgart, Germany
| | - Martin A. Lysak
- grid.10267.320000 0001 2194 0956CEITEC - Central European Institute of Technology, and Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Polina Yu. Novikova
- grid.511033.5VIB-UGent Center for Plant Systems Biology, Ghent, Belgium ,grid.419498.90000 0001 0660 6765Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Magnus Nordborg
- grid.24194.3a0000 0000 9669 8503Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
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5
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Gui F, Lan T, Zhao Y, Guo W, Dong Y, Fang D, Liu H, Li H, Wang H, Hao R, Cheng X, Li Y, Yang P, Sahu SK, Chen Y, Cheng L, He S, Liu P, Fan G, Lu H, Hu G, Dong W, Chen B, Jiang Y, Zhang Y, Xu H, Lin F, Slippers B, Postma A, Jackson M, Abate BA, Tesfaye K, Demie AL, Bayeleygne MD, Degefu DT, Chen F, Kuria PK, Kinyua ZM, Liu TX, Yang H, Huang F, Liu X, Sheng J, Kang L. Genomic and transcriptomic analysis unveils population evolution and development of pesticide resistance in fall armyworm Spodoptera frugiperda. Protein Cell 2020; 13:513-531. [PMID: 33108584 PMCID: PMC9226219 DOI: 10.1007/s13238-020-00795-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/15/2020] [Indexed: 11/24/2022] Open
Abstract
The fall armyworm (FAW), Spodoptera frugiperda, is a destructive pest native to America and has recently become an invasive insect pest in China. Because of its rapid spread and great risks in China, understanding of FAW genetic background and pesticide resistance is urgent and essential to develop effective management strategies. Here, we assembled a chromosome-level genome of a male FAW (SFynMstLFR) and compared re-sequencing results of the populations from America, Africa, and China. Strain identification of 163 individuals collected from America, Africa and China showed that both C and R strains were found in the American populations, while only C strain was found in the Chinese and African populations. Moreover, population genomics analysis showed that populations from Africa and China have close relationship with significantly genetic differentiation from American populations. Taken together, FAWs invaded into China were most likely originated from Africa. Comparative genomics analysis displayed that the cytochrome p450 gene family is extremely expanded to 425 members in FAW, of which 283 genes are specific to FAW. Treatments of Chinese populations with twenty-three pesticides showed the variant patterns of transcriptome profiles, and several detoxification genes such as AOX, UGT and GST specially responded to the pesticides. These findings will be useful in developing effective strategies for management of FAW in China and other invaded areas.
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Affiliation(s)
- Furong Gui
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan Agricultural University, Kunming, 650201, China.,Yunnan Plateau Characteristic Agriculture Industry Research Institute, Kunming, 650201, China
| | - Tianming Lan
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China.,Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Yue Zhao
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan Agricultural University, Kunming, 650201, China
| | - Wei Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Yang Dong
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan Agricultural University, Kunming, 650201, China.,Yunnan Plateau Characteristic Agriculture Industry Research Institute, Kunming, 650201, China
| | - Dongming Fang
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Huan Liu
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China.,Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Haimeng Li
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Hongli Wang
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Ruoshi Hao
- Yunnan Plateau Characteristic Agriculture Industry Research Institute, Kunming, 650201, China
| | | | - Yahong Li
- Yunnan Plant Protection and Quarantine Station, Kunming, 650034, China
| | - Pengcheng Yang
- Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, 100101, China
| | - Sunil Kumar Sahu
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Yaping Chen
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan Agricultural University, Kunming, 650201, China
| | - Le Cheng
- BGI-Yunnan, No. 389 Haiyuan Road, High-tech Development Zone, Kunming, 650106, China
| | - Shuqi He
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan Agricultural University, Kunming, 650201, China
| | - Ping Liu
- MGI, BGI-Shenzhen, Shenzhen, 518083, China
| | - Guangyi Fan
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | - Haorong Lu
- China National GeneBank, Jinsha Road, Dapeng New District, Shenzhen, 518120, China.,Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen, 518120, China
| | - Guohai Hu
- China National GeneBank, Jinsha Road, Dapeng New District, Shenzhen, 518120, China.,Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen, 518120, China
| | - Wei Dong
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Bin Chen
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan Agricultural University, Kunming, 650201, China
| | - Yuan Jiang
- BGI-Americas, One Broadway, 14th Floor, Cambridge, MA, 02142, USA
| | - Yongwei Zhang
- BGI-Americas, One Broadway, 14th Floor, Cambridge, MA, 02142, USA
| | - Hanhong Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
| | - Fei Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
| | - Bernard Slippers
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Alisa Postma
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Matthew Jackson
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | | | - Kassahun Tesfaye
- Ethiopian Biotechnology Institute, Addis Ababa, Ethiopia.,College of Natural Science, Addis Ababa University, Addis Ababa, Ethiopia
| | | | | | - Dawit Tesfaye Degefu
- Melkassa Agricultural Research Center, Ethiopian Institute of Agricultural Research, Melkassa, Addis Ababa, Ethiopia
| | - Feng Chen
- MGI, BGI-Shenzhen, Shenzhen, 518083, China
| | - Paul K Kuria
- Kenya Agricultural and Livestock Research Organization, P.O. Box 57811, Nairobi, 00800, Kenya
| | - Zachary M Kinyua
- Kenya Agricultural and Livestock Research Organization, P.O. Box 57811, Nairobi, 00800, Kenya
| | - Tong-Xian Liu
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, 266109, China
| | - Huanming Yang
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen, 518120, China.,Guangdong Provincial Academician Workstation of BGI Synthetic Genomics, BGI-Shenzhen, Shenzhen, 518120, China
| | - Fangneng Huang
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA, 70803, USA.
| | - Xin Liu
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China. .,Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen, 518120, China.
| | - Jun Sheng
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan Agricultural University, Kunming, 650201, China. .,Yunnan Plateau Characteristic Agriculture Industry Research Institute, Kunming, 650201, China.
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. .,Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, 100101, China. .,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100101, China.
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6
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Onuma R, Hirooka S, Kanesaki Y, Fujiwara T, Yoshikawa H, Miyagishima SY. Changes in the transcriptome, ploidy, and optimal light intensity of a cryptomonad upon integration into a kleptoplastic dinoflagellate. THE ISME JOURNAL 2020; 14:2407-2423. [PMID: 32514116 PMCID: PMC7490267 DOI: 10.1038/s41396-020-0693-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/19/2020] [Accepted: 05/27/2020] [Indexed: 11/30/2022]
Abstract
Endosymbiosis of unicellular eukaryotic algae into previously nonphotosynthetic eukaryotes has established chloroplasts in several eukaryotic lineages. In addition, certain unicellular organisms in several different lineages ingest algae and utilize them as temporal chloroplasts (kleptoplasts) for weeks to months before digesting them. Among these organisms, the dinoflagellate Nusuttodinium aeruginosum ingests the cryptomonad Chroomonas sp. and enlarges the kleptoplast with the aid of the cryptomonad nucleus. To understand how the cryptomonad nucleus is remodeled in the dinoflagellate, here we examined changes in the transcriptome and ploidy of the ingested nucleus. We show that, after ingestion, genes involved in metabolism, translation, and DNA replication are upregulated while those involved in sensory systems and cell motility are downregulated. In the dinoflagellate cell, the cryptomonad nucleus undergoes polyploidization that correlates with an increase in the mRNA levels of upregulated genes. In addition, the ingested nucleus almost loses transcriptional responses to light. Because polyploidization and loss of transcriptional regulation are also known to have occurred during the establishment of endosymbiotic organelles, these changes are probably a common trend in endosymbiotic evolution. Furthermore, we show that the kleptoplast and dinoflagellate are more susceptible to high light than the free-living cryptomonad but that the ingested nucleus reduces this damage.
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Affiliation(s)
- Ryo Onuma
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan.
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan
| | - Yu Kanesaki
- Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529, Japan
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Yata 1111, Mishima, Shizuoka, 411-8540, Japan
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan.
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Yata 1111, Mishima, Shizuoka, 411-8540, Japan.
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7
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Vinson CC, Mota APZ, Porto BN, Oliveira TN, Sampaio I, Lacerda AL, Danchin EGJ, Guimaraes PM, Williams TCR, Brasileiro ACM. Characterization of raffinose metabolism genes uncovers a wild Arachis galactinol synthase conferring tolerance to abiotic stresses. Sci Rep 2020; 10:15258. [PMID: 32943670 PMCID: PMC7498584 DOI: 10.1038/s41598-020-72191-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 07/31/2020] [Indexed: 12/31/2022] Open
Abstract
Raffinose family oligosaccharides (RFOs) are implicated in plant regulatory mechanisms of abiotic stresses tolerance and, despite their antinutritional proprieties in grain legumes, little information is available about the enzymes involved in RFO metabolism in Fabaceae species. In the present study, the systematic survey of legume proteins belonging to five key enzymes involved in the metabolism of RFOs (galactinol synthase, raffinose synthase, stachyose synthase, alpha-galactosidase, and beta-fructofuranosidase) identified 28 coding-genes in Arachis duranensis and 31 in A. ipaënsis. Their phylogenetic relationships, gene structures, protein domains, and chromosome distribution patterns were also determined. Based on the expression profiling of these genes under water deficit treatments, a galactinol synthase candidate gene (AdGolS3) was identified in A. duranensis. Transgenic Arabidopsis plants overexpressing AdGolS3 exhibited increased levels of raffinose and reduced stress symptoms under drought, osmotic, and salt stresses. Metabolite and expression profiling suggested that AdGolS3 overexpression was associated with fewer metabolic perturbations under drought stress, together with better protection against oxidative damage. Overall, this study enabled the identification of a promising GolS candidate gene for metabolic engineering of sugars to improve abiotic stress tolerance in crops, whilst also contributing to the understanding of RFO metabolism in legume species.
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Affiliation(s)
- Christina C Vinson
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil
- Departamento de Botânica, Universidade de Brasília, Campus Darcy Ribeiro, Brasília, DF, Brazil
| | - Ana P Z Mota
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil
| | - Brenda N Porto
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil
| | - Thais N Oliveira
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil
| | - Iracyara Sampaio
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil
- Departamento de Botânica, Universidade de Brasília, Campus Darcy Ribeiro, Brasília, DF, Brazil
| | - Ana L Lacerda
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil
| | | | - Patricia M Guimaraes
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil
| | - Thomas C R Williams
- Departamento de Botânica, Universidade de Brasília, Campus Darcy Ribeiro, Brasília, DF, Brazil
| | - Ana C M Brasileiro
- EMBRAPA Recursos Genéticos e Biotecnologia. Parque Estação Biológica, Final W5 Norte, Brasília, DF, CP 02372, Brazil.
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8
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Similar genomic patterns of clinical infective endocarditis and oral isolates of Streptococcus sanguinis and Streptococcus gordonii. Sci Rep 2020; 10:2728. [PMID: 32066773 PMCID: PMC7026040 DOI: 10.1038/s41598-020-59549-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 01/28/2020] [Indexed: 11/20/2022] Open
Abstract
Streptococcus gordonii and Streptococcus sanguinis belong to the Mitis group streptococci, which mostly are commensals in the human oral cavity. Though they are oral commensals, they can escape their niche and cause infective endocarditis, a severe infection with high mortality. Several virulence factors important for the development of infective endocarditis have been described in these two species. However, the background for how the commensal bacteria, in some cases, become pathogenic is still not known. To gain a greater understanding of the mechanisms of the pathogenic potential, we performed a comparative analysis of 38 blood culture strains, S. sanguinis (n = 20) and S. gordonii (n = 18) from patients with verified infective endocarditis, along with 21 publicly available oral isolates from healthy individuals, S. sanguinis (n = 12) and S. gordonii (n = 9). Using whole genome sequencing data of the 59 streptococci genomes, functional profiles were constructed, using protein domain predictions based on the translated genes. These functional profiles were used for clustering, phylogenetics and machine learning. A clear separation could be made between the two species. No clear differences between oral isolates and clinical infective endocarditis isolates were found in any of the 675 translated core-genes. Additionally, random forest-based machine learning and clustering of the pan-genome data as well as amino acid variations in the core-genome could not separate the clinical and oral isolates. A total of 151 different virulence genes was identified in the 59 genomes. Among these homologs of genes important for adhesion and evasion of the immune system were found in all of the strains. Based on the functional profiles and virulence gene content of the genomes, we believe that all analysed strains had the ability to become pathogenic.
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9
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Wideman JG, Monier A, Rodríguez-Martínez R, Leonard G, Cook E, Poirier C, Maguire F, Milner DS, Irwin NAT, Moore K, Santoro AE, Keeling PJ, Worden AZ, Richards TA. Unexpected mitochondrial genome diversity revealed by targeted single-cell genomics of heterotrophic flagellated protists. Nat Microbiol 2019; 5:154-165. [PMID: 31768028 DOI: 10.1038/s41564-019-0605-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 10/08/2019] [Indexed: 11/09/2022]
Abstract
Most eukaryotic microbial diversity is uncultivated, under-studied and lacks nuclear genome data. Mitochondrial genome sampling is more comprehensive, but many phylogenetically important groups remain unsampled. Here, using a single-cell sorting approach combining tubulin-specific labelling with photopigment exclusion, we sorted flagellated heterotrophic unicellular eukaryotes from Pacific Ocean samples. We recovered 206 single amplified genomes, predominantly from underrepresented branches on the tree of life. Seventy single amplified genomes contained unique mitochondrial contigs, including 21 complete or near-complete mitochondrial genomes from formerly under-sampled phylogenetic branches, including telonemids, katablepharids, cercozoans and marine stramenopiles, effectively doubling the number of available samples of heterotrophic flagellate mitochondrial genomes. Collectively, these data identify a dynamic history of mitochondrial genome evolution including intron gain and loss, extensive patterns of genetic code variation and complex patterns of gene loss. Surprisingly, we found that stramenopile mitochondrial content is highly plastic, resembling patterns of variation previously observed only in plants.
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Affiliation(s)
- Jeremy G Wideman
- Living Systems Institute, University of Exeter, Exeter, UK. .,Wissenschaftskolleg zu Berlin, Berlin, Germany. .,Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada. .,Center for Mechanisms of Evolution, Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, AZ, USA.
| | - Adam Monier
- Living Systems Institute, University of Exeter, Exeter, UK
| | - Raquel Rodríguez-Martínez
- Living Systems Institute, University of Exeter, Exeter, UK.,Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Guy Leonard
- Living Systems Institute, University of Exeter, Exeter, UK
| | - Emily Cook
- Living Systems Institute, University of Exeter, Exeter, UK
| | - Camille Poirier
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.,Ocean EcoSystems Biology Unit, Division of Marine Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Finlay Maguire
- Living Systems Institute, University of Exeter, Exeter, UK.,Faculty of Computer Science, Dalhousie University, Halifax, Nova Scotia, Canada
| | - David S Milner
- Living Systems Institute, University of Exeter, Exeter, UK
| | - Nicholas A T Irwin
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Karen Moore
- Living Systems Institute, University of Exeter, Exeter, UK
| | - Alyson E Santoro
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Patrick J Keeling
- Faculty of Computer Science, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Alexandra Z Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.,Ocean EcoSystems Biology Unit, Division of Marine Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
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10
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Whittaker L, Hao C, Fu W, Whittaker J. High-affinity insulin binding: insulin interacts with two receptor ligand binding sites. Biochemistry 2009; 47:12900-9. [PMID: 18991400 DOI: 10.1021/bi801693h] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interaction of insulin with its receptor is complex. Kinetic and equilibrium binding studies suggest coexistence of high- and low-affinity binding sites or negative cooperativity. These phenomena and high-affinity interactions are dependent on the dimeric structure of the receptor. Structure-function studies of insulin analogs suggest insulin has two receptor binding sites, implying a bivalent interaction with the receptor. Alanine scanning studies of the secreted recombinant receptor implicate the L1 domain and a C-terminal peptide of the receptor alpha subunit as components of one ligand binding site. Functional studies suggest that the first and second type III fibronectin repeats of the receptor contain a second ligand binding site. We have used structure-directed alanine scanning mutagenesis to identify determinants in these domains involved in ligand interactions. cDNAs encoding alanine mutants of the holo-receptor were transiently expressed in 293 cells, and the binding properties of the expressed receptor were determined. Alanine mutations of Lys(484), Leu(552), Asp(591), Ile(602), Lys(616), Asp(620), and Pro(621) compromised affinities for insulin 2-5-fold. With the exception of Asp(620), none of these mutations compromised the affinity of the recombinant secreted receptor for insulin, indicating that the perturbation of the interaction is at the site of mutation and not an indirect effect on the interaction with the binding site of the secreted receptor. These residues thus form part of a novel ligand binding site of the insulin receptor. Complementation experiments demonstrate that insulin interacts in trans with both receptor binding sites to generate high-affinity interactions.
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Affiliation(s)
- Linda Whittaker
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106, USA
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11
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Whittaker J, Whittaker L. Characterization of the Functional Insulin Binding Epitopes of the Full-length Insulin Receptor. J Biol Chem 2005; 280:20932-6. [PMID: 15799978 DOI: 10.1074/jbc.m411320200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mutational analyses of the secreted recombinant insulin receptor extracellular domain have identified a ligand binding site composed of residues located in the L1 domain (amino acids 1-470) and at the C terminus of the alpha subunit (amino acids 705-715). To evaluate the physiological significance of this ligand binding site, we have transiently expressed cDNAs encoding full-length receptors with alanine mutations of the residues forming the functional epitopes of this binding site and determined their insulin binding properties. Insulin bound to wild-type receptors with complex kinetics, which were fitted to a two-component sequential model; the Kd of the high affinity component was 0.03 nM and that of the low affinity component was 0.4 nM. Mutations of Arg14, Phe64, Phe705, Glu706, Tyr708, Asn711, and Val715 inactivated the receptor. Alanine mutation of Asn15 resulted in a 20-fold decrease in affinity, whereas mutations of Asp12, Gln34, Leu36, Leu37, Leu87, Phe89, Tyr91, Lys121, Leu709, and Phe714 all resulted in 4-10-fold decreases. When the effects of the mutations were compared with those of the same mutations of the secreted recombinant receptor, significant differences were observed for Asn15, Leu37, Asp707, Leu709, Tyr708, Asn711, Phe714, and Val715, suggesting that the molecular basis for the interaction of each form of the receptor with insulin differs. We also examined the effects of alanine mutations of Asn15, Gln34, and Phe89 on insulin-induced receptor autophosphorylation. They had no effect on the maximal response to insulin but produced an increase in the EC50 commensurate with their effect on the affinity of the receptor for insulin.
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Affiliation(s)
- Jonathan Whittaker
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106-4906, USA.
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12
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Chakravarty A, Hinrichsen J, Whittaker L, Whittaker J. Rescue of ligand binding of a mutant IGF-I receptor by complementation. Biochem Biophys Res Commun 2005; 331:74-7. [PMID: 15845360 DOI: 10.1016/j.bbrc.2005.03.122] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Indexed: 11/26/2022]
Abstract
The IGF-I receptor binds IGF-I with complex kinetics characterized by a curvilinear Scatchard plot, suggesting receptor heterogeneity and apparent negative cooperativity. To explore the molecular mechanisms underlying these properties, we have characterized the binding of a hybrid receptor formed from a wild-type receptor monomer and a mutant receptor monomer devoid of binding activity. Receptor hybrids were generated by transient co-transfection of cDNAs encoding wild-type and mutant receptors with unique epitope tags. Hybrid receptors were purified from transfected cells by sequential immuno-affinity chromatography and their ligand-binding properties were determined. Complementation produced a hybrid with near wild-type affinity. Dissociation studies demonstrated that the hybrid did not exhibit negative cooperativity.
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Affiliation(s)
- Anders Chakravarty
- Receptor Biology Laboratory, Novo Nordisk A/S, Hagedorn Research Institute, DK-2820 Gentofte, Denmark
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13
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Bevan AP, Christensen JR, Tikerpae J, Smith GD. Chloroquine augments the binding of insulin to its receptor. Biochem J 1995; 311 ( Pt 3):787-95. [PMID: 7487933 PMCID: PMC1136071 DOI: 10.1042/bj3110787] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The effect of chloroquine on the interaction of insulin with its receptor has been investigated under both equilibrium and non-equilibrium conditions. Chloroquine was found to augment insulin binding in a pH-dependent manner between pH 6.0 and pH 8.5, with the maximum occurring at approximately pH 7.0. Analysis of the equilibrium binding data in terms of independent binding sites gave equivocal results but suggested an increase in the high-affinity component. Analysis using the negative co-operativity binding model of De Meyts, Bianco and Roth [J. Biol. Chem. (1976) 251, 1877-1888] suggested that the affinity at both high and low occupancy was increased equally. The kinetics of association of insulin with the plasma-membrane receptor indicated that, although the net rate of association increased in the presence of chloroquine, this was due to a reduction in the dissociation rate rather than an increase in the association rate. This was confirmed by direct measurement of the rates of dissociation. Dissociation was found to be distinctly biphasic, with fast and slow components. Curve fitting suggested that the decrease in dissociation rate in the presence of chloroquine was not due to a decrease in either of the two dissociation rate constants, but rather to an increase in the amount of insulin dissociating by the slow component. It was also found that the increase in dissociation rate in the presence of excess insulin, ascribed to negative co-operativity, could be accounted for by an increase in the amount of insulin dissociating by the faster pathway, rather than by an increase in the dissociation rate constant. Thus chloroquine appears to have the opposite effect to excess insulin, and evidence was found for the induction of positive co-operativity in the insulin-receptor interaction at high chloroquine concentrations. Evidence was also found for the presence of low-affinity chloroquine binding sites with binding parameters similar to the concentration dependence of the chloroquine-induced augmentation of insulin binding.
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Affiliation(s)
- A P Bevan
- Polypeptide Hormone Laboratory, McGill University, Montreal, Quebec, Canada
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14
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De Meyts P. The structural basis of insulin and insulin-like growth factor-I receptor binding and negative co-operativity, and its relevance to mitogenic versus metabolic signalling. Diabetologia 1994; 37 Suppl 2:S135-48. [PMID: 7821729 DOI: 10.1007/bf00400837] [Citation(s) in RCA: 219] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Insulin and insulin-like growth factor-I exhibit a set of non-classical receptor binding properties suggestive of negative co-operativity or site-site interactions between the two receptor halves: curvilinear Scatchard plots, acceleration of dissociation of bound labelled ligand at high dilution in the presence of unlabelled ligand. The alpha 2 beta 2 receptor dimer binds only one ligand molecule with high affinity. The dose-response curve for the acceleration of 125I-insulin by unlabelled insulin is bell-shaped, with a disappearance of the negative co-operativity at insulin concentrations over 0.1 mumol/l. This phenomenon had been attributed to insulin dimerization, but new data with non-dimerizing analogues and insulins modified at the hexamer-forming surface indicate the presence of a second binding site on the insulin molecule's hexamer face. This site binds to a second domain on the receptor. A new binding model for insulin and insulin-like growth factor-I is proposed where the bivalent ligand bridges the two receptor alpha subunits alternatively at opposite sites in a symmetrical receptor structure. The implications of the model for negative co-operativity, bell-shaped biological curves, and the divergence between mitogenic and metabolic signalling are discussed in the context of the evolution of the properties of insulin and insulin-like growth factor-I.
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MESH Headings
- Amino Acid Sequence
- Animals
- Awards and Prizes
- Belgium
- Cell Division
- Diabetes Mellitus/history
- Europe
- Exons
- History, 20th Century
- Humans
- Insulin/physiology
- Insulin-Like Growth Factor I/physiology
- Macromolecular Substances
- Models, Molecular
- Models, Structural
- Receptor, IGF Type 1/chemistry
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/physiology
- Receptor, Insulin/chemistry
- Receptor, Insulin/genetics
- Receptor, Insulin/physiology
- Signal Transduction
- Societies, Medical
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Affiliation(s)
- P De Meyts
- Hagedorn Research Institute, Gentofte, Denmark
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15
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Lee AW. Signal transduction by the colony-stimulating factor-1 receptor; comparison to other receptor tyrosine kinases. CURRENT TOPICS IN CELLULAR REGULATION 1992; 32:73-181. [PMID: 1318184 DOI: 10.1016/b978-0-12-152832-4.50005-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- A W Lee
- Clinical Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
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16
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Flörke RR, Klein HW, Reinauer H. Structural requirements for signal transduction of the insulin receptor. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 191:473-82. [PMID: 2200676 DOI: 10.1111/j.1432-1033.1990.tb19146.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Structural requirements for signal processing by human placental insulin receptors have been examined. Insulin binding has been found to change the physico-chemical properties of (alpha beta)2 receptors solubilized with Triton X-100, indicating a marked alteration of the form, i.e. size and shape, of the molecular complex. (a) The Stokes radius decreases from about 9.5 nm to 7.9 nm, as determined by PAGE with Triton X-100 in the buffer (Triton X-100/PAGE), and from 9.1 nm to 8.7 nm, as assessed by gel filtration. (b) The sedimentation coefficient s20,w rises from 10.1 S to 11.4 S. Upon dissociation of the receptor-hormone complex, the alterations are reversed. After autophosphorylation of hormone-bound (alpha beta)2-insulin receptors, phosphate incorporation was found for 7.9-nm receptor forms when receptor-insulin complexes were crosslinked with disuccinimide suberate prior to Triton X-100/PAGE. However, phosphate incorporation was demonstrated for the 9.5-nm receptor forms when receptor-insulin complexes were not prevented from dissociation. This strongly indicates that the (alpha beta)2 receptor is autophosphorylated after assuming its 7.9-nm form upon insulin binding. Moreover, the insulin-dependent structural alterations are not affected by autophosphorylation. In contrast to (alpha beta)2 receptors, the diffusion and the sedimentation behaviour of alpha beta receptors, which carry a dormant tyrosine kinase even in the hormone-laden state, has been found to be insensitive to insulin binding. Different molecular properties of alpha beta and (alpha beta)2 receptors have also been detected by hormone binding studies. Insulin binding to (alpha beta)2 and alpha beta receptors differs markedly with respect to pH, ionic strength, and temperature. This might indicate that the structure of the hormone binding domain of alpha beta receptor changes on association into the (alpha beta)2 species. Alternatively, distinct hormone-induced conformational alterations at the molecular level of alpha beta and (alpha beta)2 receptor species may lead to the different binding properties. Our data demonstrate that the (alpha beta)2-insulin receptor undergoes extended conformational alterations upon insulin binding. This capacity for structural changes coincides with the hormone-inducable enhancement of tyrosine autophosphorylation of the 7.9-nm insulin-bound receptor form. In contrast, alpha beta receptors appear to be locked in an inactive nonconvertable state. Thus, interaction between two alpha beta receptor units is required to allow extended conformational alterations, which are assumed to be the triggering event for augmented auto-phosphorylation.
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Affiliation(s)
- R R Flörke
- Diabetes-Forschungsinstitut an der Heinrich-Heine-Universität Düsseldorf, Federal Republic of Germany
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17
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Joost HG, Göke R, Schmitz-Salue C, Steinfelder HJ, Brandenburg D. Quantitative dissociation of glucose transport stimulation and insulin receptor tyrosine kinase activation in isolated adipocytes with a covalent insulin dimer (B29,B29'-suberoyl-insulin). Biochem Pharmacol 1989; 38:2269-77. [PMID: 2546561 DOI: 10.1016/0006-2952(89)90465-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The covalent insulin dimer B29,B29'-suberoyl-insulin was investigated for its effects on insulin receptor binding, insulin receptor tyrosine kinase activity and glucose transport in isolated adipose cells. The dimer stimulated glucose transport (initial 3-O-methylglucose uptake rate) to the same extent as insulin did (basal rate, 35 +/- 3 pmol/sec/microliter lipid; insulin, 380 +/- 27; B29,B29'-suberoyl-insulin, 369 +/- 24, means +/- S.E.), although at higher concentrations (EC50 1.94 +/- 0.64 nM versus 0.1 +/- 0.02 with insulin). In contrast, the dimer only partially (23%) mimicked insulin's effect on phosphate incorporation into insulin receptors immunoprecipitated after equilibration of cells with [32P]phosphate. Similarly, insulin receptor tyrosine kinase as assessed by receptor autophosphorylation and phosphorylation of the substrate poly-(Glu/Tyr) was not fully activated by treatment of cells with the insulin dimer (31 and 42% of the effect of insulin, respectively) in concentrations which maximally activate glucose transport and give rise to full insulin receptor occupancy (5 X 10(-7) M). Further, the dimer activated the receptor tyrosine kinase in solubilized purified insulin receptor preparations from adipose cells to only 25% of the effect of insulin (EC50 32.0 +/- 16 versus 1.9 +/- 1.0 nM with insulin) in spite of full receptor occupancy. Binding of the dimer to insulin receptors followed single site binding kinetics, indicating that the derivative is unable to induce negative cooperativity of the insulin receptor. It is concluded that a partial phosphorylation of insulin receptors and a submaximal tyrosine kinase activation are sufficient for full stimulation of glucose transport in the adipocyte. Further, it is suggested that negative cooperativity of the insulin receptor and activation of its tyrosine kinase require a similar conformational change of the receptor protein.
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Affiliation(s)
- H G Joost
- Institute of Pharmacology und Toxicology, University of Göttingen, Federal Republic of Germany
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18
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Swanson ML, Pessin JE. High affinity insulin binding in the human placenta insulin receptor requires alpha beta heterodimeric subunit interactions. J Membr Biol 1989; 108:217-25. [PMID: 2674449 DOI: 10.1007/bf01871736] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Insulin binding to human placenta membranes treated at pH 7.6 or 8.5 in the presence or absence of 2.0 mM DTT for 5 min, followed by the simultaneous removal of the DTT and pH adjustment to pH 7.6, displayed curvilinear (heterogeneous) insulin binding plots when analyzed by the method of Scatchard. However, Triton X-100 solubilization followed by Bio-Gel A-1.5m gel filtration chromatography of the placenta membranes previously treated with DTT at pH 8.5 generated a nearly straight line (homogeneous) Scatchard plot. 125I-insulin affinity crosslinking studies coupled with Bio-Gel A-1.5m gel filtration chromatography demonstrated that the alkaline pH and DTT treatment of placenta membranes followed by detergent solubilization generated an alpha beta heterodimeric insulin receptor complex from the alpha 2 beta 2 heterotetrameric disulfide-linked state. The ability of alkaline pH and DTT to produce a functional alpha beta heterodimeric insulin receptor complex was found to be time dependent with maximal formation and preservation of tracer insulin binding occurring at 5 min. These data demonstrate that (i) a combination of alkaline pH and DTT treatment of placenta membranes can result in the formation of a functional alpha beta heterodimeric insulin receptor complex. (ii) the alpha beta heterodimeric complex displays homogeneous insulin binding. (iii) the insulin receptor membrane environment maintains the alpha 2 beta 2 association state, which displays heterogeneous insulin binding, despite reduction of the critical domains that are responsible for the covalent interaction between the alpha beta heterodimers.
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Affiliation(s)
- M L Swanson
- Department of Physiology & Biophysics, University of Iowa, Iowa City 52242
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19
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Wang CC, Goldfine ID, Fujita-Yamaguchi Y, Gattner HG, Brandenburg D, De Meyts P. Negative and positive site-site interactions, and their modulation by pH, insulin analogs, and monoclonal antibodies, are preserved in the purified insulin receptor. Proc Natl Acad Sci U S A 1988; 85:8400-4. [PMID: 3054887 PMCID: PMC282465 DOI: 10.1073/pnas.85.22.8400] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The kinetic properties of the insulin receptor were studied in solution after its purification to homogeneity. Dissociation of 125I-labeled insulin at a 1:50 dilution was not first order; unlabeled insulin at physiological concentrations accelerated the dissociation rate with a maximal effect at approximately 17 nM. At higher concentrations, the unlabeled insulin slowed the dissociation rate. Maximal acceleration was seen at pH 8.0. The ability to accelerate the dissociation rate was diminished with [LeuB24]insulin and suppressed with desoctapeptide, [LeuB25], [LeuB24,B25], desalanine-desasparagine, and desheptapeptide insulins, all of which slowed the dissociation at high concentrations. Monoclonal antibodies to the insulin receptor alpha subunit (MA-5, MA-10, MA-20, and MA-51) all competed for insulin binding to the purified receptor. MA-10 and MA-51 accelerated the dissociation of 125I-labeled insulin, while MA-5 and MA-20 slowed the off rate. Thus, all the aspects of both negatively and positively cooperative site-site interactions previously described in whole cells are present in solubilized purified receptors, demonstrating that these interactions represent intrinsic properties of the receptor molecule, most likely as a result of ligand-induced conformational changes.
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Affiliation(s)
- C C Wang
- Department of Diabetes, Endocrinology and Metabolism, City of Hope National Medical Center, Duarte, CA 91010
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20
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Morrison BD, Swanson ML, Sweet LJ, Pessin JE. Insulin-dependent covalent reassociation of isolated alpha beta heterodimeric insulin receptors into an alpha 2 beta 2 heterotetrameric disulfide-linked complex. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68570-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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21
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Feltz SM, Swanson ML, Wemmie JA, Pessin JE. Functional properties of an isolated alpha beta heterodimeric human placenta insulin-like growth factor 1 receptor complex. Biochemistry 1988; 27:3234-42. [PMID: 2968813 DOI: 10.1021/bi00409a017] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Treatment of human placenta membranes at pH 8.5 in the presence of 2.0 mM dithiothreitol (DTT) for 5 min, followed by the simultaneous removal of the DTT and pH adjustment to pH 7.6, resulted in the formation of a functional alpha beta heterodimeric insulin-like growth factor 1 (IGF-1) receptor complex from the native alpha 2 beta 2 heterotetrameric disulfide-linked state. The membrane-bound alpha beta heterodimeric complex displayed similar curvilinear 125I-IGF-1 equilibrium binding compared to the alpha 2 beta 2 heterotetrameric complex. Triton X-100 solubilization of the alkaline pH and DTT-pretreated placenta membranes, followed by Bio-Gel A-1.5m gel filtration chromatography, was found to effectively separate the alpha 2 beta 2 heterotetrameric and alpha beta heterodimeric IGF-1 receptor species, 125I-IGF-1 binding to both the isolated alpha 2 beta 2 heterotetrameric and alpha beta heterodimeric complexes demonstrated a marked straightening of the Scatchard plots, compared to the placenta membrane-bound IGF-1 receptors, with a 2-fold increase in the high-affinity binding component. Similar to the membrane-bound IGF-1 receptor species, the 125I-IGF-1 binding properties between the alpha 2 beta 2 heterotetrameric and alpha beta heterodimeric complexes were not significantly different. IGF-1 stimulation of IGF-1 receptor autophosphorylation indicated that the ligand-dependent activation of alpha beta heterodimeric protein kinase activity occurred concomitant with the reassociation into a covalent alpha 2 beta 2 heterotetrameric state.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S M Feltz
- Department of Physiology and Biophysics, University of Iowa, Iowa City 52242
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22
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Fujita-Yamaguchi Y, Harmon JT. A monomer-dimer model explains the results of radiation inactivation: binding characteristics of insulin receptor purified from human placenta. Biochemistry 1988; 27:3252-60. [PMID: 3291945 DOI: 10.1021/bi00409a020] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The technique of radiation inactivation has been used on highly purified human placental insulin receptor in order to determine the functional molecular size responsible for the insulin binding and to evaluate the "affinity regulator" hypothesis, which has been proposed to explain the increase in specific insulin binding to rat liver membranes observed at low radiation doses [Harmon, J. T., Hedo, J. A., & Kahn, C. R. (1983) J. Biol. Chem. 258, 6875-6881]. Three different types of inactivation curves were observed: (1) biphasic with an enhanced binding activity after exposure to low radiation doses, (2) nonlinear with no change in binding activity after exposure to low radiation doses, and (3) linear with a loss in the binding activity with increasing radiation exposures. A monomer-dimer model was the simplest model that best described the three types of radiation inactivation curves observed. The model predicts that an increase in insulin binding activity would result after exposure to low radiation doses when the initial dimer/monomer ratio is equal to or greater than 1 and a monomer is more active than a dimer. The monomer size of the binding activity was estimated to be 227,000 daltons by this model. This value most likely reflects the size of the monomeric alpha beta form. To substantiate this model, the purified receptor was fractionated by Sepharose CL-6B chromatography. The insulin binding profile of this column indicated two peaks.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- Y Fujita-Yamaguchi
- Department of Molecular Genetics, Beckman Research Institute of the City of Hope, Duarte, California 91010
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23
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Ellis L, Sissom J, Levitan A. Truncation of the ectodomain of the human insulin receptor results in secretion of a soluble insulin binding protein from transfected CHO cells. J Mol Recognit 1988; 1:25-31. [PMID: 3078838 DOI: 10.1002/jmr.300010106] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The insulin receptor is an integral transmembrane glycoprotein comprised of two alpha-(approximately 135 kDa) and two beta-(approximately 95 kDa) subunits, which is synthesized as a single polypeptide chain precursor (alpha beta). The primary sequence of the human insulin receptor (hIR) protein, deduced from the nucleotide sequence of cloned human placental mRNAs, predicts two large domains (929 and 403 residues) on either side of a single membrane spanning domain (23 residues); each of these major domains has a distinct function (insulin binding and protein/tyrosine kinase activity, respectively). To experimentally test this deduced topology, and to explore the potential for independent domain function by the hIR extracellular domain, we have constructed an expression plasmid encoding an hIR deletion mutant which is truncated 8 residues from the beginning of the predicted transmembrane domain (i.e., 921 residues). This domain of the hIR is in fact processed into alpha- and truncated beta-subunits and secreted with high efficiency from transfected CHO cell lines which express this mutant hIR, and the protein accumulates as an (alpha beta)2 dimer in the medium. This molecule is recognized by a battery of 13 monoclonal antibodies to epitopes on the IR extracellular domain, four of which block insulin binding and two of which require the native conformation of the IR for recognition. Further, this domain binds insulin with an apparent dissociation constant comparable to that of the wild-type hIR. However, the secreted dimer displays a linear Scatchard plot, while that of the wild-type membrane-associated hIR is curvilinear.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L Ellis
- Howard Hughes Medical Institute, Dallas, TX
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24
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Gu JL, Goldfine ID, Forsayeth JR, De Meyts P. Reversal of insulin-induced negative cooperativity by monoclonal antibodies that stabilize the slowly dissociating ("Ksuper") state of the insulin receptor. Biochem Biophys Res Commun 1988; 150:694-701. [PMID: 3277631 DOI: 10.1016/0006-291x(88)90447-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Two monoclonal antibodies to the insulin receptor, MA-5 and MA-20, unlike other monoclonal antibodies, do not mimick the accelerating effect of insulin on the dissociation of 125I-insulin from the receptors (negative cooperativity). On the contrary, MA-5 and MA-20 markedly slow down the dissociation rate. We show now that MA-5 and MA-20 are potent antagonists of the negative cooperativity induced by insulin, and reverse the insulin-induced acceleration whether added simultaneously with insulin or after insulin. The reversal of the insulin-induced acceleration is almost immediate. These data strengthen the concept therefore that the insulin-receptor complex has access to alternative conformational states that can be stabilized by ligand-induced site-site interactions.
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Affiliation(s)
- J L Gu
- Department of Diabetes, Endocrinology and Metabolism, City of Hope National Medical Center, Duarte, CA 91010
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25
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Sweet LJ, Morrison BD, Wilden PA, Pessin JE. Insulin-dependent intermolecular subunit communication between isolated alpha beta heterodimeric insulin receptor complexes. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)49316-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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Krämer H, Deger A, Koch R, Rapp R, Hinz M, Weber U. Generation of oligomeric insulin receptor forms by intramolecular sulfhydryl-disulfide exchange. Involvement of masked sulfhydryl groups. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1987; 368:471-9. [PMID: 3304334 DOI: 10.1515/bchm3.1987.368.1.471] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Insulin receptors from rat liver membranes were labelled with a 125I-labelled photoreactive insulin analogue or by iodination using lactoperoxidase and analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Under nonreducing conditions different receptor forms with Mr 400,000 (alpha 2 beta 2), 360,000 (alpha 2 beta beta'), 330,000 (alpha 2 beta' beta'), 320,000 (alpha 2 beta), 280,000 (alpha 2 beta'), 240,000 (alpha 2), 210,000 (alpha beta), 165,000 (alpha beta') and 115,000 (alpha) were detected. The subunit composition of these receptor forms was determined by two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis in the absence and presence of dithioerythritol. During denaturation in sodium dodecyl sulfate in the absence of reductants, the Mr 400,000 receptor form (alpha 2 beta 2) was converted into the Mr 320,000 (alpha 2 beta) and Mr 240,000 (alpha 2) receptor form. This conversion was prevented either by N-ethylmaleimide, oxidants, or low pH. In contrast, alkylation of the receptor with N-ethylmaleimide under non-denaturing conditions did not prevent the appearance of intermediate-sized receptor forms. Furthermore, the inhibition of receptor cleavage by N-ethylmaleimide during denaturation was also observed when the amount of free sulfhydryl groups was reconstituted by the addition of an unlabelled and non-alkylated receptor sample to the alkylated and photoaffinity-labelled receptor. These results suggest, that the generation of different oligomeric receptor forms detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis is due at least in part to the cleavage of one or both beta-subunits from the insulin receptor.(ABSTRACT TRUNCATED AT 250 WORDS)
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Effect of monoclonal antibodies on human insulin receptor autophosphorylation, negative cooperativity, and down-regulation. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61322-5] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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