1
|
Câmara AS, Kubalová I, Schubert V. Helical chromonema coiling is conserved in eukaryotes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1284-1300. [PMID: 37840457 DOI: 10.1111/tpj.16484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 09/07/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023]
Abstract
Efficient chromatin condensation is required to transport chromosomes during mitosis and meiosis, forming daughter cells. While it is well accepted that these processes follow fundamental rules, there has been a controversial debate for more than 140 years on whether the higher-order chromatin organization in chromosomes is evolutionarily conserved. Here, we summarize historical and recent investigations based on classical and modern methods. In particular, classical light microscopy observations based on living, fixed, and treated chromosomes covering a wide range of plant and animal species, and even in single-cell eukaryotes suggest that the chromatids of large chromosomes are formed by a coiled chromatin thread, named the chromonema. More recently, these findings were confirmed by electron and super-resolution microscopy, oligo-FISH, molecular interaction data, and polymer simulation. Altogether, we describe common and divergent features of coiled chromonemata in different species. We hypothesize that chromonema coiling in large chromosomes is a fundamental feature established early during the evolution of eukaryotes to handle increasing genome sizes.
Collapse
Affiliation(s)
- Amanda Souza Câmara
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
| | - Ivona Kubalová
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
| |
Collapse
|
2
|
Marmorale LJ, Jin H, Reidy TG, Palomino-Alonso B, Zysnarski CJ, Jordan-Javed F, Lahiri S, Duncan MC. Fast-evolving cofactors regulate the role of HEATR5 complexes in intra-Golgi trafficking. J Cell Biol 2024; 223:e202309047. [PMID: 38240799 PMCID: PMC10798858 DOI: 10.1083/jcb.202309047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/22/2023] [Accepted: 12/18/2023] [Indexed: 01/22/2024] Open
Abstract
The highly conserved HEATR5 proteins are best known for their roles in membrane traffic mediated by the adaptor protein complex-1 (AP1). HEATR5 proteins rely on fast-evolving cofactors to bind to AP1. However, how HEATR5 proteins interact with these cofactors is unknown. Here, we report that the budding yeast HEATR5 protein, Laa1, functions in two biochemically distinct complexes. These complexes are defined by a pair of mutually exclusive Laa1-binding proteins, Laa2 and the previously uncharacterized Lft1/Yml037c. Despite limited sequence similarity, biochemical analysis and structure predictions indicate that Lft1 and Laa2 bind Laa1 via structurally similar mechanisms. Both Laa1 complexes function in intra-Golgi recycling. However, only the Laa2-Laa1 complex binds to AP1 and contributes to its localization. Finally, structure predictions indicate that human HEATR5 proteins bind to a pair of fast-evolving interacting partners via a mechanism similar to that observed in yeast. These results reveal mechanistic insight into how HEATR5 proteins bind their cofactors and indicate that Laa1 performs functions besides recruiting AP1.
Collapse
Affiliation(s)
- Lucas J. Marmorale
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Huan Jin
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Thomas G. Reidy
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Brandon Palomino-Alonso
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Christopher J. Zysnarski
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Fatima Jordan-Javed
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Sagar Lahiri
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Mara C. Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| |
Collapse
|
3
|
Marmorale LJ, Jin H, Reidy TG, Palomino-Alonso B, Zysnarski C, Jordan-Javed F, Lahiri S, Duncan MC. Two functionally distinct HEATR5 protein complexes are defined by fast-evolving co-factors in yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554671. [PMID: 37662263 PMCID: PMC10473696 DOI: 10.1101/2023.08.24.554671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The highly conserved HEATR5 proteins are best known for their roles in membrane traffic mediated by the adaptor protein complex-1 (AP1). HEATR5 proteins rely on fast-evolving co-factors to bind to AP1. However, how HEATR5 proteins interact with these co-factors is unknown. Here, we report that the budding yeast HEATR5 protein, Laa1, functions in two biochemically distinct complexes. These complexes are defined by a pair of mutually exclusive Laa1-binding proteins, Laa2 and the previously uncharacterized Lft1/Yml037c. Despite limited sequence similarity, biochemical analysis and structure predictions indicate that Lft1 and Laa2 bind Laa1 via structurally similar mechanisms. Both Laa1 complexes function in intra-Golgi recycling. However, only the Laa2-Laa1 complex binds to AP1 and contributes to its localization. Finally, structure predictions indicate that human HEATR5 proteins bind to a pair of fast-evolving interacting partners via a mechanism similar to that observed in yeast. These results reveal mechanistic insight into how HEATR5 proteins bind their co-factors and indicate that Laa1 performs functions besides recruiting AP1.
Collapse
Affiliation(s)
- Lucas J. Marmorale
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
- Present address: Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ
| | - Huan Jin
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
| | - Thomas G. Reidy
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
- Present address: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | | | | | - Fatima Jordan-Javed
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
| | - Sagar Lahiri
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
| | - Mara C Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
| |
Collapse
|
4
|
Pal P, Alley JR, Townsend CA. Examining Heterodimerization by Aryl C-N Coupling in Dynemicin Biosynthesis. ACS Chem Biol 2023; 18:304-314. [PMID: 36696117 DOI: 10.1021/acschembio.2c00709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Distinct among the enediyne antitumor antibiotics, the dynemicin subgroup is comprised of two discrete halves, an enediyne and an anthraquinone, but each is ultimately derived from the same linear β-hydroxyhexaene precursor. The linkage of these two halves by an aryl C-N bond is examined here using a variety of experimental approaches. We demonstrate that this heterodimerization is specific for anthracenyl iodide as the corresponding bromo- and amino-substituted anthracenes do not support dynemicin biosynthesis. Furthermore, biochemical experiments and chemical model reactions support an SRN1 mechanism for the aryl C-N coupling in which electron transfer occurs to the iodoanthracene, followed by loss of an anthracenyl iodide and partition of the resulting aryl radical between C-N coupling and reduction by hydrogen abstraction. An enzyme pull-down experiment aiming to capture the protein(s) involved in the coupling reaction is described in which two proteins, Orf14 and Orf16, encoded by the dynemicin biosynthetic gene cluster, are specifically isolated. Deletion of orf14 from the genome abolished dynemicin production accompanied by a 3-fold increased accumulation of the iodoanthracene coupling partner, indicating the plausible involvement of this protein in the heterodimerization process. On the other hand, the deletion of orf16 only reduced dynemicin production to 55%, implying a noncatalytic, auxiliary role of the protein. Structural comparisons using AlphaFold imply key similarities between Orf14 and X-ray crystal structures of several proteins from enediyne BGCs believed to bind hydrophobic polyene or enediyne motifs suggest Orf14 templates aryl C-N bond formation during the central heterodimerization in dynemicin biosynthesis.
Collapse
Affiliation(s)
- Paramita Pal
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jamie R Alley
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Craig A Townsend
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| |
Collapse
|
5
|
Donnelly KM, Coleman CM, Fuller ML, Reed VL, Smerina D, Tomlinson DS, Pearce MMP. Hunting for the cause: Evidence for prion-like mechanisms in Huntington’s disease. Front Neurosci 2022; 16:946822. [PMID: 36090278 PMCID: PMC9448931 DOI: 10.3389/fnins.2022.946822] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/28/2022] [Indexed: 11/23/2022] Open
Abstract
The hypothesis that pathogenic protein aggregates associated with neurodegenerative diseases spread from cell-to-cell in the brain in a manner akin to infectious prions has gained substantial momentum due to an explosion of research in the past 10–15 years. Here, we review current evidence supporting the existence of prion-like mechanisms in Huntington’s disease (HD), an autosomal dominant neurodegenerative disease caused by expansion of a CAG repeat tract in exon 1 of the huntingtin (HTT) gene. We summarize information gained from human studies and in vivo and in vitro models of HD that strongly support prion-like features of the mutant HTT (mHTT) protein, including potential involvement of molecular features of mHTT seeds, synaptic structures and connectivity, endocytic and exocytic mechanisms, tunneling nanotubes, and nonneuronal cells in mHTT propagation in the brain. We discuss mechanisms by which mHTT aggregate spreading and neurotoxicity could be causally linked and the potential benefits of targeting prion-like mechanisms in the search for new disease-modifying therapies for HD and other fatal neurodegenerative diseases.
Collapse
Affiliation(s)
- Kirby M. Donnelly
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Cevannah M. Coleman
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Madison L. Fuller
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Victoria L. Reed
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Dayna Smerina
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - David S. Tomlinson
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Margaret M. Panning Pearce
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
- Department of Biology, Saint Joseph’s University, Philadelphia, PA, United States
- *Correspondence: Margaret M. Panning Pearce,
| |
Collapse
|
6
|
Crystal Structures of Wolbachia CidA and CidB Reveal Determinants of Bacteria-induced Cytoplasmic Incompatibility and Rescue. Nat Commun 2022; 13:1608. [PMID: 35338130 PMCID: PMC8956670 DOI: 10.1038/s41467-022-29273-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 03/03/2022] [Indexed: 02/05/2023] Open
Abstract
Cytoplasmic incompatibility (CI) results when Wolbachia bacteria-infected male insects mate with uninfected females, leading to embryonic lethality. “Rescue” of viability occurs if the female harbors the same Wolbachia strain. CI is caused by linked pairs of Wolbachia genes called CI factors (CifA and CifB). The co-evolution of CifA-CifB pairs may account in part for the incompatibility patterns documented in insects infected with different Wolbachia strains, but the molecular mechanisms remain elusive. Here, we use X-ray crystallography and AlphaFold to analyze the CI factors from Wolbachia strain wMel called CidAwMel and CidBwMel. Substituting CidAwMel interface residues with those from CidAwPip (from strain wPip) enables the mutant protein to bind CidBwPip and rescue CidBwPip-induced yeast growth defects, supporting the importance of CifA-CifB interaction in CI rescue. Sequence divergence in CidAwPip and CidBwPip proteins affects their pairwise interactions, which may help explain the complex incompatibility patterns of mosquitoes infected with different wPip strains. Wolbachia induced cytoplasmic incompatibility (CI) is caused by linked pairs of genes named cifA and cifB. Here, authors show that the residues at interfaces of the CidA-CidB complex is crucial for their binding and contribute to the diversity of CI.
Collapse
|
7
|
Trujillo-Del Río C, Tortajada-Pérez J, Gómez-Escribano AP, Casterá F, Peiró C, Millán JM, Herrero MJ, Vázquez-Manrique RP. Metformin to treat Huntington disease: a pleiotropic drug against a multi-system disorder. Mech Ageing Dev 2022; 204:111670. [DOI: 10.1016/j.mad.2022.111670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 12/17/2022]
|
8
|
Structural and mechanistic insights into the complexes formed by Wolbachia cytoplasmic incompatibility factors. Proc Natl Acad Sci U S A 2021; 118:2107699118. [PMID: 34620712 DOI: 10.1073/pnas.2107699118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2021] [Indexed: 11/18/2022] Open
Abstract
Wolbachia bacteria, inherited through the female germ line, infect a large fraction of arthropod species. Many Wolbachia strains manipulate host reproduction, most commonly through cytoplasmic incompatibility (CI). CI, a conditional male sterility, results when Wolbachia-infected male insects mate with uninfected females; viability is restored if the female is similarly infected (called "rescue"). CI is used to help control mosquito-borne viruses such as dengue and Zika, but its mechanisms remain unknown. The coexpressed CI factors CifA and CifB form stable complexes in vitro, but the timing and function of this interaction in the insect are unresolved. CifA expression in the female germ line is sufficient for rescue. We report high-resolution structures of a CI-factor complex, CinA-CinB, which utilizes a unique binding mode between the CinA rescue factor and the CinB nuclease; the structures were validated by biochemical and yeast growth analyses. Importantly, transgenic expression in Drosophila of a nonbinding CinA mutant, designed based on the CinA-CinB structure, suggests CinA expressed in females must bind CinB imported by sperm in order to rescue embryonic viability. Binding between cognate factors is conserved in an enzymatically distinct CI system, CidA-CidB, suggesting universal features in Wolbachia CI induction and rescue.
Collapse
|
9
|
Eshraghi M, Karunadharma PP, Blin J, Shahani N, Ricci EP, Michel A, Urban NT, Galli N, Sharma M, Ramírez-Jarquín UN, Florescu K, Hernandez J, Subramaniam S. Mutant Huntingtin stalls ribosomes and represses protein synthesis in a cellular model of Huntington disease. Nat Commun 2021; 12:1461. [PMID: 33674575 PMCID: PMC7935949 DOI: 10.1038/s41467-021-21637-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
The polyglutamine expansion of huntingtin (mHTT) causes Huntington disease (HD) and neurodegeneration, but the mechanisms remain unclear. Here, we found that mHtt promotes ribosome stalling and suppresses protein synthesis in mouse HD striatal neuronal cells. Depletion of mHtt enhances protein synthesis and increases the speed of ribosomal translocation, while mHtt directly inhibits protein synthesis in vitro. Fmrp, a known regulator of ribosome stalling, is upregulated in HD, but its depletion has no discernible effect on protein synthesis or ribosome stalling in HD cells. We found interactions of ribosomal proteins and translating ribosomes with mHtt. High-resolution global ribosome footprint profiling (Ribo-Seq) and mRNA-Seq indicates a widespread shift in ribosome occupancy toward the 5' and 3' end and unique single-codon pauses on selected mRNA targets in HD cells, compared to controls. Thus, mHtt impedes ribosomal translocation during translation elongation, a mechanistic defect that can be exploited for HD therapeutics.
Collapse
Affiliation(s)
- Mehdi Eshraghi
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Pabalu P. Karunadharma
- grid.214007.00000000122199231The Scripps Research Institute, Genomic Core, Jupiter, FL USA
| | - Juliana Blin
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | - Neelam Shahani
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Emiliano P. Ricci
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | | | | | - Nicole Galli
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Manish Sharma
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Uri Nimrod Ramírez-Jarquín
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Katie Florescu
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Jennifer Hernandez
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Srinivasa Subramaniam
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| |
Collapse
|
10
|
Chang CC, Hsia KC. More than a zip code: global modulation of cellular function by nuclear localization signals. FEBS J 2020; 288:5569-5585. [PMID: 33296547 DOI: 10.1111/febs.15659] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Extensive structural and functional studies have been carried out in the field of nucleocytoplasmic transport. Nuclear transport factors, such as Importin-α/-β, recognize nuclear localization signals (NLSs) on cargo, and together with the small GTPase Ran, facilitate their nuclear localization. However, it is now emerging that binding of nuclear transport factors to NLSs not only mediates nuclear transport but also contributes to a variety of cellular functions in eukaryotes. Here, we describe recent advances that reveal how NLSs facilitate diverse cellular functions beyond nuclear transport activity. We review separately NLS-mediated regulatory mechanisms at different levels of biological organization, including (a) assembly of higher-order structures; (b) cellular organelle dynamics; and (c) modulation of cellular stress responses and viral infections. Finally, we provide mechanistic insights into how NLSs can regulate such a broad range of functions via their structural and biochemical properties.
Collapse
Affiliation(s)
- Chih-Chia Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kuo-Chiang Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang-Ming University, Taipei, Taiwan
| |
Collapse
|
11
|
Jung T, Shin B, Tamo G, Kim H, Vijayvargia R, Leitner A, Marcaida MJ, Astorga-Wells J, Jung R, Aebersold R, Peraro MD, Hebert H, Seong IS, Song JJ. The Polyglutamine Expansion at the N-Terminal of Huntingtin Protein Modulates the Dynamic Configuration and Phosphorylation of the C-Terminal HEAT Domain. Structure 2020; 28:1035-1050.e8. [PMID: 32668197 PMCID: PMC11059206 DOI: 10.1016/j.str.2020.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 04/01/2020] [Accepted: 06/23/2020] [Indexed: 11/15/2022]
Abstract
The polyQ expansion in huntingtin protein (HTT) is the prime cause of Huntington's disease (HD). The recent cryoelectron microscopy (cryo-EM) structure of HTT-HAP40 complex provided the structural information on its HEAT-repeat domains. Here, we present analyses of the impact of polyQ length on the structure and function of HTT via an integrative structural and biochemical approach. The cryo-EM analysis of normal (Q23) and disease (Q78) type HTTs shows that the structures of apo HTTs significantly differ from the structure of HTT in a HAP40 complex and that the polyQ expansion induces global structural changes in the relative movements among the HTT domains. In addition, we show that the polyQ expansion alters the phosphorylation pattern across HTT and that Ser2116 phosphorylation in turn affects the global structure and function of HTT. These results provide a molecular basis for the effect of the polyQ segment on HTT structure and activity, which may be important for HTT pathology.
Collapse
Affiliation(s)
- Taeyang Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea; School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 141 52 Huddinge, Sweden; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden
| | - Baehyun Shin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Giorgio Tamo
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Hyeongju Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea
| | - Ravi Vijayvargia
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Maria J Marcaida
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Juan Astorga-Wells
- Department of Medical Biochemistry & Biophysics, Karolinska Institutet, 171 65 Solna, Sweden; HDxperts AB, 183 48 Täby, Sweden
| | - Roy Jung
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland; Faculty of Science, University of Zürich, Zürich, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Hans Hebert
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 141 52 Huddinge, Sweden; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden.
| | - Ihn Sik Seong
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA.
| | - Ji-Joon Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea.
| |
Collapse
|
12
|
Stairiker CJ, van Meurs M, Leon LG, Brouwers-Haspels AA, Rijsbergen L, Mueller YM, Katsikis PD. Heatr9 is an infection responsive gene that affects cytokine production in alveolar epithelial cells. PLoS One 2020; 15:e0236195. [PMID: 32678841 PMCID: PMC7367486 DOI: 10.1371/journal.pone.0236195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/30/2020] [Indexed: 12/23/2022] Open
Abstract
During infection, viruses enter susceptible host cells in order to replicate their components for production of new virions. In the process of infection, the gene expression of infected cells undergoes changes because of the production of viral components and due to the host response from detection of viral products. In the advent of RNA sequencing, the discovery of new genes and their functions in the host response generates new avenues for interventions in the host-pathogen interaction. We have identified a novel gene, Heatr9, as a virus and cytokine inducible viral responsive gene. We confirm Heatr9’s expression in vitro and in vivo during virus infection and correlate it with viral burden. Heatr9 is induced by influenza virus and RSV. Heatr9 knockdown during viral infection was shown to affect chemokine expression. Our studies identify Heatr9 as a novel inflammatory and virus infection induced gene that can regulate the induction of specific cytokines.
Collapse
Affiliation(s)
- Christopher J. Stairiker
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Marjan van Meurs
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Leticia G. Leon
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - A. A. Brouwers-Haspels
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Laurine Rijsbergen
- Department of Virology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Yvonne M. Mueller
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Peter D. Katsikis
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- * E-mail:
| |
Collapse
|
13
|
Gibcus JH, Samejima K, Goloborodko A, Samejima I, Naumova N, Nuebler J, Kanemaki MT, Xie L, Paulson JR, Earnshaw WC, Mirny LA, Dekker J. A pathway for mitotic chromosome formation. Science 2018; 359:eaao6135. [PMID: 29348367 PMCID: PMC5924687 DOI: 10.1126/science.aao6135] [Citation(s) in RCA: 426] [Impact Index Per Article: 71.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/09/2018] [Indexed: 12/23/2022]
Abstract
Mitotic chromosomes fold as compact arrays of chromatin loops. To identify the pathway of mitotic chromosome formation, we combined imaging and Hi-C analysis of synchronous DT40 cell cultures with polymer simulations. Here we show that in prophase, the interphase organization is rapidly lost in a condensin-dependent manner, and arrays of consecutive 60-kilobase (kb) loops are formed. During prometaphase, ~80-kb inner loops are nested within ~400-kb outer loops. The loop array acquires a helical arrangement with consecutive loops emanating from a central "spiral staircase" condensin scaffold. The size of helical turns progressively increases to ~12 megabases during prometaphase. Acute depletion of condensin I or II shows that nested loops form by differential action of the two condensins, whereas condensin II is required for helical winding.
Collapse
Affiliation(s)
- Johan H Gibcus
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Kumiko Samejima
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Anton Goloborodko
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Itaru Samejima
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Natalia Naumova
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Johannes Nuebler
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Masato T Kanemaki
- Division of Molecular Cell Engineering, National Institute of Genetics, Research Organization of Information and Systems, and Department of Genetics, SOKENDAI, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Linfeng Xie
- Department of Chemistry, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA
| | - James R Paulson
- Department of Chemistry, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK.
| | - Leonid A Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
- Howard Hughes Medical Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| |
Collapse
|
14
|
Horani A, Ustione A, Huang T, Firth AL, Pan J, Gunsten SP, Haspel JA, Piston DW, Brody SL. Establishment of the early cilia preassembly protein complex during motile ciliogenesis. Proc Natl Acad Sci U S A 2018; 115:E1221-E1228. [PMID: 29358401 PMCID: PMC5819421 DOI: 10.1073/pnas.1715915115] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Motile cilia are characterized by dynein motor units, which preassemble in the cytoplasm before trafficking into the cilia. Proteins required for dynein preassembly were discovered by finding human mutations that result in absent ciliary motors, but little is known about their expression, function, or interactions. By monitoring ciliogenesis in primary airway epithelial cells and MCIDAS-regulated induced pluripotent stem cells, we uncovered two phases of expression of preassembly proteins. An early phase, composed of HEATR2, SPAG1, and DNAAF2, preceded other preassembly proteins and was independent of MCIDAS regulation. The early preassembly proteins colocalized within perinuclear foci that also contained dynein arm proteins. These proteins also interacted based on immunoprecipitation and Förster resonance energy transfer (FRET) studies. FRET analysis of HEAT domain deletions and human mutations showed that HEATR2 interacted with itself and SPAG1 at multiple HEAT domains, while DNAAF2 interacted with SPAG1. Human mutations in HEATR2 did not affect this interaction, but triggered the formation of p62/Sequestosome-1-positive aggregates containing the early preassembly proteins, suggesting that degradation of an early preassembly complex is responsible for disease and pointing to key regions required for HEATR2 scaffold stability. We speculate that HEATR2 is an early scaffold for the initiation of dynein complex assembly in motile cilia.
Collapse
Affiliation(s)
- Amjad Horani
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110;
| | - Alessandro Ustione
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Tao Huang
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Amy L Firth
- Department of Medicine, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033
| | - Jiehong Pan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Sean P Gunsten
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Jeffrey A Haspel
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Steven L Brody
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| |
Collapse
|
15
|
Rakesh R, Krishnan R, Sattlegger E, Srinivasan N. Recognition of a structural domain (RWDBD) in Gcn1 proteins that interacts with the RWD domain containing proteins. Biol Direct 2017; 12:12. [PMID: 28526057 PMCID: PMC5438488 DOI: 10.1186/s13062-017-0184-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/12/2017] [Indexed: 11/12/2022] Open
Abstract
Abstract The protein Gcn1 (General control non-derepressible 1) is found in virtually all eukaryotes, and is a key component of the general amino acid control signal transduction pathway. This pathway is best known for its importance for cells to sense and overcome amino acid starvation. Gcn1 directly binds to the RWD (RING finger-containing proteins, WD-repeat-containing proteins, and yeast DEAD (DEXD)-like helicases) domain of the protein kinase Gcn2, and this is essential for delivering the starvation signal to Gcn2. Gcn2, and thus the GAAC (General Amino Acid Control) pathway, then becomes activated enabling the cell to cope and overcome the starvation condition. Using sensitive homology detection and fold recognition methods a conserved structural domain in Gcn1, RWD Binding Domain (RWDBD), has been recognized that encompasses the region experimentally shown previously to be involved in Gcn2 binding. Further, the structural fold for this domain has been recognized as the ARM (Armadillo) domain, and residues likely to be involved in the binding of Gcn2 RWD domain have been identified within this structural domain. Thus, the current analysis provides a structural basis of Gcn1-Gcn2 association. Reviewers This article was reviewed by Dr Oliviero Carugo and Dr Michael Gromiha. Electronic supplementary material The online version of this article (doi:10.1186/s13062-017-0184-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ramachandran Rakesh
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Rangachari Krishnan
- Institute of Natural and Mathematical Sciences (INMS), Massey University, Auckland, 0745, New Zealand
| | - Evelyn Sattlegger
- Institute of Natural and Mathematical Sciences (INMS), Massey University, Auckland, 0745, New Zealand.
| | | |
Collapse
|
16
|
Listeria monocytogenes DNA Glycosylase AdlP Affects Flagellar Motility, Biofilm Formation, Virulence, and Stress Responses. Appl Environ Microbiol 2016; 82:5144-52. [PMID: 27316964 PMCID: PMC4988193 DOI: 10.1128/aem.00719-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/09/2016] [Indexed: 12/16/2022] Open
Abstract
The temperature-dependent alteration of flagellar motility gene expression is critical for the foodborne pathogen Listeria monocytogenes to respond to a changing environment. In this study, a genetic determinant, L. monocytogenesf2365_0220 (lmof2365_0220), encoding a putative protein that is structurally similar to the Bacillus cereus alkyl base DNA glycosylase (AlkD), was identified. This determinant was involved in the transcriptional repression of flagellar motility genes and was named adlP (encoding an AlkD-like protein [AdlP]). Deletion of adlP activated the expression of flagellar motility genes at 37°C and disrupted the temperature-dependent inhibition of L. monocytogenes motility. The adlP null strains demonstrated decreased survival in murine macrophage-like RAW264.7 cells and less virulence in mice. Furthermore, the deletion of adlP significantly decreased biofilm formation and impaired the survival of bacteria under several stress conditions, including the presence of a DNA alkylation compound (methyl methanesulfonate), an oxidative agent (H2O2), and aminoglycoside antibiotics. Our findings strongly suggest that adlP may encode a bifunctional protein that transcriptionally represses the expression of flagellar motility genes and influences stress responses through its DNA glycosylase activity. IMPORTANCE We discovered a novel protein that we named AlkD-like protein (AdlP). This protein affected flagellar motility, biofilm formation, and virulence. Our data suggest that AdlP may be a bifunctional protein that represses flagellar motility genes and influences stress responses through its DNA glycosylase activity.
Collapse
|
17
|
Rakesh R, Joseph AP, Bhaskara RM, Srinivasan N. Structural and mechanistic insights into human splicing factor SF3b complex derived using an integrated approach guided by the cryo-EM density maps. RNA Biol 2016; 13:1025-1040. [PMID: 27618338 DOI: 10.1080/15476286.2016.1218590] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Pre-mRNA splicing in eukaryotes is performed by the spliceosome, a highly complex macromolecular machine. SF3b is a multi-protein complex which recognizes the branch point adenosine of pre-mRNA as part of a larger U2 snRNP or U11/U12 di-snRNP in the dynamic spliceosome machinery. Although a cryo-EM map is available for human SF3b complex, the structure and relative spatial arrangement of all components in the complex are not yet known. We have recognized folds of domains in various proteins in the assembly and generated comparative models. Using an integrative approach involving structural and other experimental data, guided by the available cryo-EM density map, we deciphered a pseudo-atomic model of the closed form of SF3b which is found to be a "fuzzy complex" with highly flexible components and multiplicity of folds. Further, the model provides structural information for 5 proteins (SF3b10, SF3b155, SF3b145, SF3b130 and SF3b14b) and localization information for 4 proteins (SF3b10, SF3b145, SF3b130 and SF3b14b) in the assembly for the first time. Integration of this model with the available U11/U12 di-snRNP cryo-EM map enabled elucidation of an open form. This now provides new insights on the mechanistic features involved in the transition between closed and open forms pivoted by a hinge region in the SF3b155 protein that also harbors cancer causing mutations. Moreover, the open form guided model of the 5' end of U12 snRNA, which includes the branch point duplex, shows that the architecture of SF3b acts as a scaffold for U12 snRNA: pre-mRNA branch point duplex formation with potential implications for branch point adenosine recognition fidelity.
Collapse
Affiliation(s)
- Ramachandran Rakesh
- a Molecular Biophysics Unit, Indian Institute of Science , Bangalore , India
| | - Agnel Praveen Joseph
- b National Center for Biological Sciences, TIFR, GKVK Campus , Bangalore , India
| | - Ramachandra M Bhaskara
- a Molecular Biophysics Unit, Indian Institute of Science , Bangalore , India.,b National Center for Biological Sciences, TIFR, GKVK Campus , Bangalore , India
| | | |
Collapse
|
18
|
Tauchert MJ, Hémonnot C, Neumann P, Köster S, Ficner R, Dickmanns A. Impact of the crystallization condition on importin-β conformation. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:705-17. [DOI: 10.1107/s2059798316004940] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/23/2016] [Indexed: 11/10/2022]
Abstract
In eukaryotic cells, the exchange of macromolecules between the nucleus and cytoplasm is highly selective and requires specialized soluble transport factors. Many of them belong to the importin-β superfamily, the members of which share an overall superhelical structure owing to the tandem arrangement of a specific motif, the HEAT repeat. This structural organization leads to great intrinsic flexibility, which in turn is a prerequisite for the interaction with a variety of proteins and for its transport function. During the passage from the aqueous cytosol into the nucleus, the receptor passes the gated channel of the nuclear pore complex filled with a protein meshwork of unknown organization, which seems to be highly selective owing to the presence of FG-repeats, which are peptides with hydrophobic patches. Here, the structural changes of free importin-β from a single organism, crystallized in polar (salt) or apolar (PEG) buffer conditions, are reported. This allowed analysis of the structural changes, which are attributable to the surrounding milieu and are not affected by bound interaction partners. The importin-β structures obtained exhibit significant conformational changes and suggest an influence of the polarity of the environment, resulting in an extended conformation in the PEG condition. The significance of this observation is supported by SAXS experiments and the analysis of other crystal structures of importin-β deposited in the Protein Data Bank.
Collapse
|
19
|
Halder K, Dölker N, Van Q, Gregor I, Dickmanns A, Baade I, Kehlenbach RH, Ficner R, Enderlein J, Grubmüller H, Neumann H. MD simulations and FRET reveal an environment-sensitive conformational plasticity of importin-β. Biophys J 2016. [PMID: 26200863 DOI: 10.1016/j.bpj.2015.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The nuclear pore complex mediates nucleocytoplasmic transport of macromolecules in eukaryotic cells. Transport through the pore is restricted by a hydrophobic selectivity filter comprising disordered phenylalanine-glycine-rich repeats of nuclear pore proteins. Exchange through the pore requires specialized transport receptors, called exportins and importins, that interact with cargo proteins in a RanGTP-dependent manner. These receptors are highly flexible superhelical structures composed of HEAT-repeat motifs that adopt various degrees of extension in crystal structures. Here, we performed molecular-dynamics simulations using crystal structures of Importin-β in its free form or in complex with nuclear localization signal peptides as the starting conformation. Our simulations predicted that initially compact structures would adopt extended conformations in hydrophilic buffers, while contracted conformations would dominate in more hydrophobic solutions, mimicking the environment of the nuclear pore. We confirmed this experimentally by Förster resonance energy transfer experiments using dual-fluorophore-labeled Importin-β. These observations explain seemingly contradictory crystal structures and suggest a possible mechanism for cargo protection during passage of the nuclear pore. Such hydrophobic switching may be a general principle for environmental control of protein function.
Collapse
Affiliation(s)
- Kangkan Halder
- Free Floater (Junior) Research Group "Applied Synthetic Biology", Institute for Microbiology and Genetics, Georg-August University Göttingen, Göttingen, Germany
| | - Nicole Dölker
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Qui Van
- Third Institute of Physics-Biophysics, Georg-August University Göttingen, Göttingen, Germany
| | - Ingo Gregor
- Third Institute of Physics-Biophysics, Georg-August University Göttingen, Göttingen, Germany
| | - Achim Dickmanns
- Institute for Microbiology and Genetics, Department of Molecular Structural Biology, Georg-August University Göttingen, Göttingen, Germany
| | - Imke Baade
- Department of Molecular Biology, Faculty of Medicine, Georg-August University Göttingen, Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Georg-August University Göttingen, Göttingen, Germany
| | - Ralf Ficner
- Institute for Microbiology and Genetics, Department of Molecular Structural Biology, Georg-August University Göttingen, Göttingen, Germany
| | - Jörg Enderlein
- Third Institute of Physics-Biophysics, Georg-August University Göttingen, Göttingen, Germany
| | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| | - Heinz Neumann
- Free Floater (Junior) Research Group "Applied Synthetic Biology", Institute for Microbiology and Genetics, Georg-August University Göttingen, Göttingen, Germany.
| |
Collapse
|
20
|
Christie M, Chang CW, Róna G, Smith KM, Stewart AG, Takeda AAS, Fontes MRM, Stewart M, Vértessy BG, Forwood JK, Kobe B. Structural Biology and Regulation of Protein Import into the Nucleus. J Mol Biol 2015; 428:2060-90. [PMID: 26523678 DOI: 10.1016/j.jmb.2015.10.023] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/16/2015] [Accepted: 10/24/2015] [Indexed: 11/28/2022]
Abstract
Proteins are translated in the cytoplasm, but many need to access the nucleus to perform their functions. Understanding how these nuclear proteins are transported through the nuclear envelope and how the import processes are regulated is therefore an important aspect of understanding cell function. Structural biology has played a key role in understanding the molecular events during the transport processes and their regulation, including the recognition of nuclear targeting signals by the corresponding receptors. Here, we review the structural basis of the principal nuclear import pathways and the molecular basis of their regulation. The pathways involve transport factors that are members of the β-karyopherin family, which can bind cargo directly (e.g., importin-β, transportin-1, transportin-3, importin-13) or through adaptor proteins (e.g., importin-α, snurportin-1, symportin-1), as well as unrelated transport factors such as Hikeshi, involved in the transport of heat-shock proteins, and NTF2, involved in the transport of RanGDP. Solenoid proteins feature prominently in these pathways. Nuclear transport factors recognize nuclear targeting signals on the cargo proteins, including the classical nuclear localization signals, recognized by the adaptor importin-α, and the PY nuclear localization signals, recognized by transportin-1. Post-translational modifications, particularly phosphorylation, constitute key regulatory mechanisms operating in these pathways.
Collapse
Affiliation(s)
- Mary Christie
- The Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales Faculty of Medicine, Darlinghurst, NSW 2010, Australia
| | - Chiung-Wen Chang
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gergely Róna
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Kate M Smith
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
| | - Alastair G Stewart
- School of Molecular Bioscience, The University of Sydney, Sydney, NSW 2006, Australia
| | - Agnes A S Takeda
- Department of Physics and Biophysics, Institute of Biosciences, Universidade Estadual Paulista, Botucatu, São Paulo 18618-000, Brazil
| | - Marcos R M Fontes
- Department of Physics and Biophysics, Institute of Biosciences, Universidade Estadual Paulista, Botucatu, São Paulo 18618-000, Brazil
| | - Murray Stewart
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Beáta G Vértessy
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia.
| |
Collapse
|
21
|
Abstract
The Toll/interleukin-1 receptor/resistance protein (TIR) domain is a protein-protein interaction domain consisting of 125-200 residues, widely distributed in animals, plants and bacteria but absent from fungi, archea and viruses. In plants and animals, these domains are found in proteins with functions in innate immune pathways, while in bacteria, some TIR domain-containing proteins interfere with the innate immune pathways in the host. TIR domains function as protein scaffolds, mostly involving self-association and homotypic interactions with other TIR domains. In the last 15 years, the three-dimensional structures of TIR domains from several mammalian, plant and bacterial proteins have been reported. These structures, jointly with functional data including the identification of interacting proteins, have started to provide insight into the molecular basis of the assembly of animal and plant immune signaling complexes, and for host immunosuppression by bacterial pathogens. This review focuses on the current knowledge of the structures of the TIR domains and how the structure relates to function.
Collapse
|
22
|
Dickmanns A, Kehlenbach RH, Fahrenkrog B. Nuclear Pore Complexes and Nucleocytoplasmic Transport: From Structure to Function to Disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 320:171-233. [PMID: 26614874 DOI: 10.1016/bs.ircmb.2015.07.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nucleocytoplasmic transport is an essential cellular activity and occurs via nuclear pore complexes (NPCs) that reside in the double membrane of the nuclear envelope. Significant progress has been made during the past few years in unravelling the ultrastructural organization of NPCs and their constituents, the nucleoporins, by cryo-electron tomography and X-ray crystallography. Mass spectrometry and genomic approaches have provided deeper insight into the specific regulation and fine tuning of individual nuclear transport pathways. Recent research has also focused on the roles nucleoporins play in health and disease, some of which go beyond nucleocytoplasmic transport. Here we review emerging results aimed at understanding NPC architecture and nucleocytoplasmic transport at the atomic level, elucidating the specific function individual nucleoporins play in nuclear trafficking, and finally lighting up the contribution of nucleoporins and nuclear transport receptors in human diseases, such as cancer and certain genetic disorders.
Collapse
Affiliation(s)
- Achim Dickmanns
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University of Göttingen, Göttingen, Germany
| | - Birthe Fahrenkrog
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Charleroi, Belgium
| |
Collapse
|
23
|
Chemosensory regulation of a HEAT-repeat protein couples aggregation and sporulation in Myxococcus xanthus. J Bacteriol 2014; 196:3160-8. [PMID: 24957622 DOI: 10.1128/jb.01866-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Chemosensory systems are complex, highly modified two-component systems (TCS) used by bacteria to control various biological functions ranging from motility to sporulation. Chemosensory systems and TCS both modulate phosphorelays comprised of histidine kinases and response regulators, some of which are single-domain response regulators (SD-RRs) such as CheY. In this study, we have identified and characterized the Che7 chemosensory system of Myxococcus xanthus, a common soil bacterium which displays multicellular development in response to stress. Both genetic and biochemical analyses indicate that the Che7 system regulates development via a direct interaction between the SD-RR CheY7 and a HEAT repeat domain-containing protein, Cpc7. Phosphorylation of the SD-RR affects the interaction with its target, and residues within the α4-β5-α5 fold of the REC domain govern this interaction. The identification of the Cpc7 interaction with CheY7 extends the diversity of known targets for SD-RRs in biological systems.
Collapse
|
24
|
Arabidopsis thaliana Tic110, involved in chloroplast protein translocation, contains at least fourteen highly divergent heat-like repeated motifs. Biologia (Bratisl) 2013. [DOI: 10.2478/s11756-013-0310-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
25
|
Dölker N, Blanchet CE, Voß B, Haselbach D, Kappel C, Monecke T, Svergun DI, Stark H, Ficner R, Zachariae U, Grubmüller H, Dickmanns A. Structural determinants and mechanism of mammalian CRM1 allostery. Structure 2013; 21:1350-60. [PMID: 23850451 DOI: 10.1016/j.str.2013.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 05/07/2013] [Accepted: 05/26/2013] [Indexed: 10/26/2022]
Abstract
Proteins carrying nuclear export signals cooperatively assemble with the export factor CRM1 and the effector protein RanGTP. In lower eukaryotes, this cooperativity is coupled to CRM1 conformational changes; however, it is unknown if mammalian CRM1 maintains its compact conformation or shows similar structural flexibility. Here, combinations of small-angle X-ray solution scattering and electron microscopy experiments with molecular dynamics simulations reveal pronounced conformational flexibility in mammalian CRM1 and demonstrate that RanGTP binding induces association of its N- and C-terminal regions to form a toroid structure. The CRM1 toroid is stabilized mainly by local interactions between the terminal regions, rather than by global strain. The CRM1 acidic loop is key in transmitting the effect of this RanGTP-induced global conformational change to the NES-binding cleft by shifting its population to the open state, which displays enhanced cargo affinity. Cooperative CRM1 export complex assembly thus constitutes a highly dynamic process, encompassing an intricate interplay of global and local structural changes.
Collapse
Affiliation(s)
- Nicole Dölker
- Abteilung für Theoretische und Computergestützte Biophysik, Max-Planck-Institut für Biophysikalische Chemie, Am Faßberg 11, 37077 Göttingen, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Bukhari SA, Caetano-Anollés G. Origin and evolution of protein fold designs inferred from phylogenomic analysis of CATH domain structures in proteomes. PLoS Comput Biol 2013; 9:e1003009. [PMID: 23555236 PMCID: PMC3610613 DOI: 10.1371/journal.pcbi.1003009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 02/13/2013] [Indexed: 12/22/2022] Open
Abstract
The spatial arrangements of secondary structures in proteins, irrespective of their connectivity, depict the overall shape and organization of protein domains. These features have been used in the CATH and SCOP classifications to hierarchically partition fold space and define the architectural make up of proteins. Here we use phylogenomic methods and a census of CATH structures in hundreds of genomes to study the origin and diversification of protein architectures (A) and their associated topologies (T) and superfamilies (H). Phylogenies that describe the evolution of domain structures and proteomes were reconstructed from the structural census and used to generate timelines of domain discovery. Phylogenies of CATH domains at T and H levels of structural abstraction and associated chronologies revealed patterns of reductive evolution, the early rise of Archaea, three epochs in the evolution of the protein world, and patterns of structural sharing between superkingdoms. Phylogenies of proteomes confirmed the early appearance of Archaea. While these findings are in agreement with previous phylogenomic studies based on the SCOP classification, phylogenies unveiled sharing patterns between Archaea and Eukarya that are recent and can explain the canonical bacterial rooting typically recovered from sequence analysis. Phylogenies of CATH domains at A level uncovered general patterns of architectural origin and diversification. The tree of A structures showed that ancient structural designs such as the 3-layer (αβα) sandwich (3.40) or the orthogonal bundle (1.10) are comparatively simpler in their makeup and are involved in basic cellular functions. In contrast, modern structural designs such as prisms, propellers, 2-solenoid, super-roll, clam, trefoil and box are not widely distributed and were probably adopted to perform specialized functions. Our timelines therefore uncover a universal tendency towards protein structural complexity that is remarkable.
Collapse
Affiliation(s)
- Syed Abbas Bukhari
- Evolutionary Bioinformatics Laboratory, Department of Crop Sciences, University of Illinois, Urbana, Illinois, United States of America
| | - Gustavo Caetano-Anollés
- Evolutionary Bioinformatics Laboratory, Department of Crop Sciences, University of Illinois, Urbana, Illinois, United States of America
| |
Collapse
|
27
|
Shertz CA, Bastidas RJ, Li W, Heitman J, Cardenas ME. Conservation, duplication, and loss of the Tor signaling pathway in the fungal kingdom. BMC Genomics 2010; 11:510. [PMID: 20863387 PMCID: PMC2997006 DOI: 10.1186/1471-2164-11-510] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 09/23/2010] [Indexed: 11/10/2022] Open
Abstract
Background The nutrient-sensing Tor pathway governs cell growth and is conserved in nearly all eukaryotic organisms from unicellular yeasts to multicellular organisms, including humans. Tor is the target of the immunosuppressive drug rapamycin, which in complex with the prolyl isomerase FKBP12 inhibits Tor functions. Rapamycin is a gold standard drug for organ transplant recipients that was approved by the FDA in 1999 and is finding additional clinical indications as a chemotherapeutic and antiproliferative agent. Capitalizing on the plethora of recently sequenced genomes we have conducted comparative genomic studies to annotate the Tor pathway throughout the fungal kingdom and related unicellular opisthokonts, including Monosiga brevicollis, Salpingoeca rosetta, and Capsaspora owczarzaki. Results Interestingly, the Tor signaling cascade is absent in three microsporidian species with available genome sequences, the only known instance of a eukaryotic group lacking this conserved pathway. The microsporidia are obligate intracellular pathogens with highly reduced genomes, and we hypothesize that they lost the Tor pathway as they adapted and streamlined their genomes for intracellular growth in a nutrient-rich environment. Two TOR paralogs are present in several fungal species as a result of either a whole genome duplication or independent gene/segmental duplication events. One such event was identified in the amphibian pathogen Batrachochytrium dendrobatidis, a chytrid responsible for worldwide global amphibian declines and extinctions. Conclusions The repeated independent duplications of the TOR gene in the fungal kingdom might reflect selective pressure acting upon this kinase that populates two proteinaceous complexes with different cellular roles. These comparative genomic analyses illustrate the evolutionary trajectory of a central nutrient-sensing cascade that enables diverse eukaryotic organisms to respond to their natural environments.
Collapse
Affiliation(s)
- Cecelia A Shertz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | | | | | | | | |
Collapse
|
28
|
Forwood JK, Lange A, Zachariae U, Marfori M, Preast C, Grubmüller H, Stewart M, Corbett AH, Kobe B. Quantitative Structural Analysis of Importin-β Flexibility: Paradigm for Solenoid Protein Structures. Structure 2010; 18:1171-83. [DOI: 10.1016/j.str.2010.06.015] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 05/04/2010] [Accepted: 06/01/2010] [Indexed: 12/24/2022]
|
29
|
Förster F, Lasker K, Nickell S, Sali A, Baumeister W. Toward an integrated structural model of the 26S proteasome. Mol Cell Proteomics 2010; 9:1666-77. [PMID: 20467039 PMCID: PMC2938054 DOI: 10.1074/mcp.r000002-mcp201] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 03/26/2010] [Indexed: 11/06/2022] Open
Abstract
The 26S proteasome is the end point of the ubiquitin-proteasome pathway and degrades ubiquitylated substrates. It is composed of the 20S core particle (CP), where degradation occurs, and the 19S regulatory particle (RP), which ensures substrate specificity of degradation. Whereas the CP is resolved to atomic resolution, the architecture of the RP is largely unknown. We provide a comprehensive analysis of the current structural knowledge on the RP, including structures of the RP subunits, physical protein-protein interactions, and cryoelectron microscopy data. These data allowed us to compute an atomic model for the CP-AAA-ATPase subcomplex. In addition to this atomic model, further subunits can be mapped approximately, which lets us hypothesize on the substrate path during its degradation.
Collapse
Affiliation(s)
- Friedrich Förster
- From the ‡Department of Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Keren Lasker
- ¶Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences (QB3), University of California, San Francisco, California 94158, and
- ‖Blavatnik School of Computer Science, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Stephan Nickell
- From the ‡Department of Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Andrej Sali
- ¶Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences (QB3), University of California, San Francisco, California 94158, and
| | - Wolfgang Baumeister
- From the ‡Department of Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| |
Collapse
|
30
|
Seong IS, Woda JM, Song JJ, Lloret A, Abeyrathne PD, Woo CJ, Gregory G, Lee JM, Wheeler VC, Walz T, Kingston RE, Gusella JF, Conlon RA, MacDonald ME. Huntingtin facilitates polycomb repressive complex 2. Hum Mol Genet 2009; 19:573-83. [PMID: 19933700 PMCID: PMC2807366 DOI: 10.1093/hmg/ddp524] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Huntington's disease (HD) is caused by expansion of the polymorphic polyglutamine segment in the huntingtin protein. Full-length huntingtin is thought to be a predominant HEAT repeat α-solenoid, implying a role as a facilitator of macromolecular complexes. Here we have investigated huntingtin's domain structure and potential intersection with epigenetic silencer polycomb repressive complex 2 (PRC2), suggested by shared embryonic deficiency phenotypes. Analysis of a set of full-length recombinant huntingtins, with different polyglutamine regions, demonstrated dramatic conformational flexibility, with an accessible hinge separating two large α-helical domains. Moreover, embryos lacking huntingtin exhibited impaired PRC2 regulation of Hox gene expression, trophoblast giant cell differentiation, paternal X chromosome inactivation and histone H3K27 tri-methylation, while full-length endogenous nuclear huntingtin in wild-type embryoid bodies (EBs) was associated with PRC2 subunits and was detected with trimethylated histone H3K27 at Hoxb9. Supporting a direct stimulatory role, full-length recombinant huntingtin significantly increased the histone H3K27 tri-methylase activity of reconstituted PRC2 in vitro, and structure–function analysis demonstrated that the polyglutamine region augmented full-length huntingtin PRC2 stimulation, both in HdhQ111 EBs and in vitro, with reconstituted PRC2. Knowledge of full-length huntingtin's α-helical organization and role as a facilitator of the multi-subunit PRC2 complex provides a novel starting point for studying PRC2 regulation, implicates this chromatin repressive complex in a neurodegenerative disorder and sets the stage for further study of huntingtin's molecular function and the impact of its modulatory polyglutamine region.
Collapse
Affiliation(s)
- Ihn Sik Seong
- Center for Human Genetic Research, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Mason DA, Stage DE, Goldfarb DS. Evolution of the metazoan-specific importin alpha gene family. J Mol Evol 2009; 68:351-65. [PMID: 19308634 DOI: 10.1007/s00239-009-9215-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 02/11/2009] [Accepted: 02/16/2009] [Indexed: 01/09/2023]
Abstract
Importin alphas are import receptors for nuclear localization signal-containing proteins. Most animal importin alphas assort into alpha1, alpha2, and alpha3 groups. Studies in Drosophila melanogaster, Caenorhabditis elegans, and mouse suggest that the animal importin alpha gene family evolved from ancestral plant-like genes to serve paralog-specific roles in gametogenesis. To explore this hypothesis we extended the phylogenetic analysis of the importin alpha gene family to nonbilateral animals and investigated whether animal-like genes occur in premetazoan taxa. Maximum likelihood analysis suggests that animal-like importin alpha genes occur in the Choanoflaggelate Monosiga brevicollis and the amoebozoan Dictyostelium; however, both of these results are caused by long-branch attraction effects. The absence of animal-like alpha genes in premetazoan taxa is consistent with the hypothesis that they duplicated and then specialized to function in animal gametogenesis. The gene structures of the importin alphas provide insight into how the animal importin alpha gene family may have evolved from the most likely ancestral gene. Interestingly, animal alpha1s are more similar to plant and fungal alpha1-like sequences than they are to animal alpha2s or alpha3s. We show that animal alpha1 genes share most of their introns with plant alpha1-like genes, and alpha2s and alpha3s share many more intron positions with each other than with the alpha1s. Together, phylogenetics and gene structure analysis suggests a parsimonious path for the evolution of the mammalian importin alpha gene family from an ancestral alpha1-like progenitor. Finally, these results establish a rational basis for a unified nomenclature of the importin alpha gene family.
Collapse
Affiliation(s)
- D Adam Mason
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | | | | |
Collapse
|
32
|
Phillips JC. Scaling and self-organized criticality in proteins I. Proc Natl Acad Sci U S A 2009; 106:3107-12. [PMID: 19218446 PMCID: PMC2651243 DOI: 10.1073/pnas.0811262106] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Indexed: 11/18/2022] Open
Abstract
The complexity of proteins is substantially simplified by regarding them as archetypical examples of self-organized criticality (SOC). To test this idea and elaborate on it, this article applies the Moret-Zebende SOC hydrophobicity scale to the large-scale scaffold repeat protein of the HEAT superfamily, PR65/A. Hydrophobic plasticity is defined and used to identify docking platforms and hinges from repeat sequences alone. The difference between the MZ scale and conventional hydrophobicity scales reflects long-range conformational forces that are central to protein functionality.
Collapse
Affiliation(s)
- J C Phillips
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA.
| |
Collapse
|
33
|
Abstract
The complexity of proteins is substantially simplified by regarding them as archetypical examples of self-organized criticality (SOC). To test this idea and to elaborate it, this article applies the Moret-Zebende (MZ) SOC hydrophobicity scale to transport repeat proteins of the HEAT superfamily, importin beta, and transportin, as well as the export protein Cse1p, and their ubiquitous cargo manager Ran. The difference between the MZ scale and conventional hydrophobicity scales reflects long-range conformational forces that are central to protein functionality. These compete with long-range Coulomb forces associated with cationic and anionic side chains in a revealing way.
Collapse
|
34
|
Abstract
This overview provides an illustrated, comprehensive survey of some commonly observed protein‐fold families and structural motifs, chosen for their functional significance. It opens with descriptions and definitions of the various elements of protein structure and associated terminology. Following is an introduction into web‐based structural bioinformatics that includes surveys of interactive web servers for protein fold or domain annotation, protein‐structure databases, protein‐structure‐classification databases, structural alignments of proteins, and molecular graphics programs available for personal computers. The rest of the overview describes selected families of protein folds in terms of their secondary, tertiary, and quaternary structural arrangements, including ribbon‐diagram examples, tables of representative structures with references, and brief explanations pointing out their respective biological and functional significance.
Collapse
Affiliation(s)
- Peter D Sun
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | | | | |
Collapse
|
35
|
Wei Z, Xue Y, Xu H, Gong W. Crystal structure of the C-terminal domain of S.cerevisiae eIF5. J Mol Biol 2006; 359:1-9. [PMID: 16616930 DOI: 10.1016/j.jmb.2006.03.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 03/08/2006] [Accepted: 03/15/2006] [Indexed: 11/19/2022]
Abstract
eIF5, a GTPase-activating protein (GAP) specific for eIF2, plays a critical role in pre-initiation complex assembly and correct AUG selection during eukaryotic translation initiation. eIF5 is involved in the formation of the multifactor complex (MFC), an important intermediate of the 43S pre-initiation complex. The C-terminal domain (CTD) of eIF5 functions as the structural core in the MFC assembly. Here we report the 1.5A crystal structure of eIF5-CTD, confirming that eIF5-CTD contains an atypical HEAT motif. In addition, analyzing the electrostatic potential and the distribution of conserved residues on the protein surface, we confirm and suggest some potential regions of interactions between eIF5-CTD and other eIFs. The structure of eIF5-CTD provides useful information in understanding the mechanism of the MFC assembly.
Collapse
Affiliation(s)
- Zhiyi Wei
- National Laboratory of Biomacromolecules, USTC-IBP Joint Laboratory for Protein Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | | | | | | |
Collapse
|
36
|
Chen MH, Ben-Efraim I, Mitrousis G, Walker-Kopp N, Sims PJ, Cingolani G. Phospholipid Scramblase 1 Contains a Nonclassical Nuclear Localization Signal with Unique Binding Site in Importin α. J Biol Chem 2005; 280:10599-606. [PMID: 15611084 DOI: 10.1074/jbc.m413194200] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nuclear import of proteins containing a classical nuclear localization signal (NLS) is an energy-dependent process that requires the heterodimer importin alpha/beta. Three to six basic contiguous arginine/lysine residues characterize a classical NLS and are thought to form a basic patch on the surface of the import cargo. In this study, we have characterized the NLS of phospholipid scramblase 1 (PLSCR1), a lipid-binding protein that enters the nucleus via the nonclassical NLS (257)GKISKHWTGI(266). This import sequence lacks a contiguous stretch of positively charged residues, and it is enriched in hydrophobic residues. We have determined the 2.2 A crystal structure of a complex between the PLSCR1 NLS and the armadillo repeat core of vertebrate importin alpha. Our crystallographic analysis reveals that PLSCR1 NLS binds to armadillo repeats 1-4 of importin alpha, but its interaction partially overlaps the classical NLS binding site. Two PLSCR1 lysines occupy the canonical positions indicated as P2 and P5. Moreover, we present in vivo evidence that the critical lysine at position P2, which is essential in other known NLS sequences, is dispensable in PLSCR1 NLS. Taken together, these data provide insight into a novel nuclear localization signal that presents a distinct motif for binding to importin alpha.
Collapse
Affiliation(s)
- Min-Hsuan Chen
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, 750, E. Adams St., Syracuse, NY 13210, USA
| | | | | | | | | | | |
Collapse
|
37
|
Gorbea C, Goellner GM, Teter K, Holmes RK, Rechsteiner M. Characterization of mammalian Ecm29, a 26 S proteasome-associated protein that localizes to the nucleus and membrane vesicles. J Biol Chem 2004; 279:54849-61. [PMID: 15496406 DOI: 10.1074/jbc.m410444200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In addition to its thirty or so core subunits, a number of accessory proteins associate with the 26 S proteasome presumably to assist in substrate degradation or to localize the enzyme within cells. Among these proteins is ecm29p, a 200-kDa yeast protein that contains numerous HEAT repeats as well as a putative VHS domain. Higher eukaryotes possess a well conserved homolog of yeast ecm29p, and we produced antibodies to three peptides in the human Ecm29 sequence. The antibodies show that Ecm29 is present exclusively on 26 S proteasomes in HeLa cells and that Ecm29 levels vary markedly among mouse organs. Confocal immunofluorescence microscopy localizes Ecm29 to the centrosome and a subset of secretory compartments including endosomes, the ER and the ERGIC. Ecm29 is up-regulated 2-3-fold in toxinresistant mutant CHO cells exhibiting increased rates of ER-associated degradation. Based on these results we propose that Ecm29 serves to couple the 26 S proteasome to secretory compartments engaged in quality control and to other sites of enhanced proteolysis.
Collapse
Affiliation(s)
- Carlos Gorbea
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
| | | | | | | | | |
Collapse
|
38
|
Wei Z, Zhang P, Zhou Z, Cheng Z, Wan M, Gong W. Crystal structure of human eIF3k, the first structure of eIF3 subunits. J Biol Chem 2004; 279:34983-90. [PMID: 15180986 DOI: 10.1074/jbc.m405158200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
eIF3k, the smallest subunit of eukaryotic initiation factor 3 (eIF3), interacts with several other subunits of eIF3 and the 40 S ribosomal subunit. eIF3k is conserved among high eukaryotes, including mammals, insects, and plants, and it is ubiquitously expressed in human tissues. Interestingly, eIF3k does not exist in some species of yeast. Thus, eIF3k may play a unique regulatory role in higher organisms. Here we report the crystal structure of human eIF3k, the first high-resolution structure of an eIF3 component. This novel structure contains two distinct domains, a HEAT (named for Huntington, elongation factor 3, A subunit of protein phosphatase 2A, target of rapamycin) repeat-like HAM (HEAT analogous motif) domain and a winged-helix-like WH domain. Through structural comparison and sequence conservation analysis, we show that eIF3k has three putative protein-binding surfaces and has potential RNA binding activity. The structure provides key information for understanding the structure and function of the eIF3 complex.
Collapse
Affiliation(s)
- Zhiyi Wei
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | | | | | | | | | | |
Collapse
|
39
|
Dlakić M, Tollervey D. The Noc proteins involved in ribosome synthesis and export contain divergent HEAT repeats. RNA (NEW YORK, N.Y.) 2004; 10:351-4. [PMID: 14970380 PMCID: PMC1370930 DOI: 10.1261/rna.5184704] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The Noc1-4p proteins were previously reported to be involved in intranuclear and nucleocytoplasmic transport of pre-ribosomes. Using fold recognition and structural modeling, we show that Noc1-4p are largely comprised of alpha-helical repeats similar to HEAT repeats. Because other HEAT-repeat proteins play key roles in transport processes, this finding provides a plausible mechanistic explanation for the function of the Noc proteins.
Collapse
|
40
|
Abstract
mTOR/RAFT1/FRAP is the target of the FKBP12-rapamycin complex as well as a central component of a nutrient- and hormone-sensitive pathway that controls cellular growth. Recent work reveals that mTOR interacts with a novel evolutionarily conserved protein that we named raptor, for "regulatory associated protein of mTOR." Raptor has several roles in the mTOR pathway. It is necessary for nutrient-mediated activation of the downstream effector S6K1 and increases in cell size. In addition, under conditions that repress the mTOR pathway, the association of raptor with mTOR is strengthened, leading to a decrease in mTOR kinase activity. Raptor is a critical component of the mTOR pathway that regulates cell growth in response to nutrient levels by associating with mTOR.
Collapse
Affiliation(s)
- D H Kim
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | | |
Collapse
|
41
|
Gard DL, Becker BE, Josh Romney S. MAPping the Eukaryotic Tree of Life: Structure, Function, and Evolution of the MAP215⧸Dis1 Family of Microtubule-Associated Proteins. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 239:179-272. [PMID: 15464854 DOI: 10.1016/s0074-7696(04)39004-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The MAP215/Dis1 family of proteins is an evolutionarily ancient family of microtubule-associated proteins, with characterized members in all major kingdoms of eukaryotes, including fungi (Stu2 in S. cerevisiae, Dis1 and Alp14 in S. pombe), Dictyostelium (DdCP224), plants (Mor1 in A. thaliana and TMBP200 in N. tabaccum), and animals (Zyg9 in C. elegans, Msps in Drosophila, XMAP215 in Xenopus, and ch-TOG in humans). All MAP215/Dis1 proteins (with the exception of those in plants) localize to microtubule-organizing centers (MTOCs), including spindle pole bodies in yeast and centrosomes in animals, and all bind to microtubules in vitro and?or in vivo. Diverse roles in regulating microtubule assembly and organization have been proposed for individual family members, and a substantial body of evidence suggests that MAP215/Dis1-related proteins play critical roles in the assembly and function of the meiotic/mitotic spindles and/or cell division. An extensive search of public databases (including both EST and genome databases) identified partial sequences predicted to encode more than three dozen new members of the MAP215/Dis1 family, including putative MAP215/Dis1-related proteins in Giardia lamblia and four other protists, sixteen additional species of fungi, six plants, and twelve animals. The structure and function of MAP215/Dis1 proteins are discussed in relation to the evolution of this ancient family of microtubule-associated proteins.
Collapse
Affiliation(s)
- David L Gard
- Department of Biology, University of Utah, Salt Lake City, Utah 84112-0840, USA
| | | | | |
Collapse
|
42
|
Abstract
Over a 4-day period of development, Drosophila larvae undergo a roughly 1,000-fold increase in mass. This impressive growth requires a continuous source of dietary protein; in the absence of amino acids, growth is arrested and various larval tissues display characteristic cell-cycle, metabolic, and structural changes. Mutations in the Drosophila target of rapamycin (dTOR) gene result in strikingly similar phenotypes, suggesting that dTOR acts in a signaling pathway responsive to nutrient availability. Genetic epistasis experiments indicate that dTOR is also required for cell growth in response to insulin and PI3K signaling, and that S6K activation can partially rescue dTOR loss of function. Thus dTOR has roles in both nutrient- and growth factor-mediated signaling, and may act to coordinate the activities of these pathways during development. Here we describe the use of mutations in dTOR to dissect its role in various signaling events, to gain insight into TOR protein structure, and to identify novel factors involved in TOR signaling.
Collapse
Affiliation(s)
- T P Neufeld
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street S.E., Minneapolis, MN 55455, USA.
| |
Collapse
|
43
|
Steggerda SM, Paschal BM. Regulation of nuclear import and export by the GTPase Ran. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 217:41-91. [PMID: 12019565 DOI: 10.1016/s0074-7696(02)17012-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review focuses on the control of nuclear import and export pathways by the small GTPase Ran. Transport of signal-containing cargo substrates is mediated by receptors that bind to the cargo proteins and RNAs and deliver them to the appropriate cellular compartment. Ran is an evolutionarily conserved member of the Ras superfamily that regulates all receptor-mediated transport between the nucleus and the cytoplasm. We describe the identification and characterization of the RanGTPase and its binding partners: the guanine nucleotide exchange factor, RanGEF; the GTPase activating protein, RanGAP; the soluble import and export receptors; Ran-binding domain-(RBD) containing proteins; and NTF2 and related factors.
Collapse
Affiliation(s)
- Susanne M Steggerda
- Center for Cell Signaling and Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville 22908, USA
| | | |
Collapse
|
44
|
Kono Y, Maeda K, Kuwahara K, Yamamoto H, Miyamoto E, Yonezawa K, Takagi K, Sakaguchi N. MCM3-binding GANP DNA-primase is associated with a novel phosphatase component G5PR. Genes Cells 2002; 7:821-34. [PMID: 12167160 DOI: 10.1046/j.1365-2443.2002.00562.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND GANP, carrying DNA-primase and MCM3-binding domains, is up-regulated in germinal centre B cells. To understand the regulatory function of GANP upon MCM complex, we searched for GANP-associated molecules by yeast two-hybrid screening. RESULTS Using the 1 kb fragment (G5) of the ganp cDNA, we identified a clone named G5PR that is structurally homologous to known regulatory subunits of protein phosphatases (PPases) and determined the association of G5PR with GANP in vivo in the DNA transfectant. G5PR is associated with protein phosphatase 5 (PP5) through its tetratricopeptide-repeat (TPR) domain. Pull-down assays demonstrated that G5PR is also associated with protein phosphatase 2A (PP2A), the complex of A subunit (PR65) and the catalytic (C) subunit (PP2Ac), similar to the B" subunit. The G5PR-associated complex had phosphatase activity on casein, histone H1 and MCM3 in vitro, but the addition of G5PR did not stimulate or inhibit the phosphatase activities of PP5 and PP2A. The cellular localization of G5PR in transfected cells varies during cell cycling, appearing in the nucleus during prophase, in the peri-chromatin during mitotic phase, and in the cytoplasm after cell division. CONCLUSION G5PR is capable of recruiting two kinds of PPases, PP5 and PP2A, into the GANP/MCM3 complex, which might regulate its phosphorylation state during cell cycle progression.
Collapse
Affiliation(s)
- Yoshihiko Kono
- Department of Immunology, Kumamoto University School of Medicine, 2-2-1, Honjo, Kumamoto, 860-0811, Japan
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
Plant microtubule arrays differ fundamentally from their animal, fungal and protistan counterparts. These differences largely reflect the requirements of plant composite polymer cell walls and probably also relate to the acquisition of chloroplasts. Plant microtubules are usually dispersed and lack conspicuous organizing centres. The key to understanding this dispersed nature is the identification of proteins that interact with and regulate the spatial and dynamic properties of microtubules. Over the past decade, a number of these proteins have been uncovered, including numerous kinesin-related proteins and a 65 kDa class of structural microtubule-associated proteins that appear to be unique to plants. Mutational analysis has identified MOR1, a probable stabilizer of microtubules that is a homologue of the TOGp-XMAP215 class of high-molecular-weight microtubule-associated proteins, and a katanin p60 subunit homologue implicated in the severing of microtubules. The identification of these two proteins provides new insights into the mechanisms controlling microtubule assembly and dynamics, particularly in the dispersed cortical array found in highly polarized plant cells.
Collapse
Affiliation(s)
- Geoffrey O Wasteneys
- Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, GPO Box 475, Canberra ACT 2601, Australia.
| |
Collapse
|
46
|
|
47
|
Lubert EJ, Hong Y, Sarge KD. Interaction between protein phosphatase 5 and the A subunit of protein phosphatase 2A: evidence for a heterotrimeric form of protein phosphatase 5. J Biol Chem 2001; 276:38582-7. [PMID: 11504734 DOI: 10.1074/jbc.m106906200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the phosphoprotein phosphatase family of serine/threonine phosphatases are thought to exist in different native oligomeric complexes. Protein phosphatase 2A (PP2A) is composed of a catalytic subunit (PP2Ac) that complexes with an A subunit, which in turn also interacts with one of many B subunits that regulate substrate specificity and/or (sub)cellular localization of the enzyme. Another family member, protein phosphatase 5 (PP5), contains a tetratricopeptide repeat domain at its N terminus, which has been suggested to mediate interactions with other proteins. PP5 was not thought to interact with partners homologous to the A or B subunits that exist within PP2A. However, our results indicate that this may not be the case. A yeast two-hybrid screen revealed an interaction between PP5 and the A subunit of PP2A. This interaction was confirmed for endogenous proteins in vivo using immunoprecipitation analysis and for recombinant proteins by in vitro binding experiments. Our results also indicate that the tetratricopeptide repeat domain of PP5 is required and sufficient for this interaction. In addition, immunoprecipitated PP5 contains associated B subunits. Thus, our results suggest that PP5 can exist in a PP2A-like heterotrimeric form containing both A and B subunits.
Collapse
Affiliation(s)
- E J Lubert
- Department of Biochemistry, University of Kentucky, Chandler Medical Center, Lexington, Kentucky 40536-0084, USA
| | | | | |
Collapse
|
48
|
Jenkins J, Pickersgill R. The architecture of parallel beta-helices and related folds. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2001; 77:111-75. [PMID: 11747907 DOI: 10.1016/s0079-6107(01)00013-x] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three-dimensional structures have been determined of a large number of proteins characterized by a repetitive fold where each of the repeats (coils) supplies a strand to one or more parallel beta-sheets. Some of these proteins form superfamilies of proteins, which have probably arisen by divergent evolution from a common ancestor. The classical example is the family including four families of pectinases without obviously related primary sequences, the phage P22 tailspike endorhamnosidase, chrondroitinase B and possibly pertactin from Bordetella pertusis. These show extensive stacking of similar residues to give aliphatic, aromatic and polar stacks such as the asparagine ladder. This suggests that coils can be added or removed by duplication or deletion of the DNA corresponding to one or more coils and explains how homologous proteins can have different numbers of coils. This process can also account for the evolution of other families of proteins such as the beta-rolls, the leucine-rich repeat proteins, the hexapeptide repeat family, two separate families of beta-helical antifreeze proteins and the spiral folds. These families need not be related to each other but will share features such as relative untwisted beta-sheets, stacking of similar residues and turns between beta-strands of approximately 90 degrees often stabilized by hydrogen bonding along the direction of the parallel beta-helix.Repetitive folds present special problems in the comparison of structures but offer attractive targets for structure prediction. The stacking of similar residues on a flat parallel beta-sheet may account for the formation of amyloid with beta-strands at right-angles to the fibril axis from many unrelated peptides.
Collapse
Affiliation(s)
- J Jenkins
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich NR4 7UA, UK.
| | | |
Collapse
|
49
|
Abstract
ARM and HEAT motifs are tandemly repeated sequences of approximately 50 amino acid residues that occur in a wide variety of eukaryotic proteins. An exhaustive search of sequence databases detected new family members and revealed that at least 1 in 500 eukaryotic protein sequences contain such repeats. It also rendered the similarity between ARM and HEAT repeats, believed to be evolutionarily related, readily apparent. All the proteins identified in the database searches could be clustered by sequence similarity into four groups: canonical ARM-repeat proteins and three groups of the more divergent HEAT-repeat proteins. This allowed us to build improved sequence profiles for the automatic detection of repeat motifs. Inspection of these profiles indicated that the individual repeat motifs of all four classes share a common set of seven highly conserved hydrophobic residues, which in proteins of known three-dimensional structure are buried within or between repeats. However, the motifs differ at several specific residue positions, suggesting important structural or functional differences among the classes. Our results illustrate that ARM and HEAT-repeat proteins, while having a common phylogenetic origin, have since diverged significantly. We discuss evolutionary scenarios that could account for the great diversity of repeats observed.
Collapse
Affiliation(s)
- M A Andrade
- European Molecular Biology Laboratory, Heidelberg, Germany
| | | | | | | | | |
Collapse
|
50
|
Neuwald AF, Hirano T. HEAT repeats associated with condensins, cohesins, and other complexes involved in chromosome-related functions. Genome Res 2000; 10:1445-52. [PMID: 11042144 PMCID: PMC310966 DOI: 10.1101/gr.147400] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2000] [Accepted: 08/17/2000] [Indexed: 11/25/2022]
Abstract
HEAT repeats correspond to tandemly arranged curlicue-like structures that appear to serve as flexible scaffolding on which other components can assemble. Using sensitive sequence analysis techniques we detected HEAT repeats in various chromosome-associated proteins, including four families of proteins associated with condensins and cohesins, which are nuclear complexes that contain structural maintenance of chromosome (SMC) proteins. Among the proteins detected were the XCAP-D2 and XCAP-G subunits of the Xenopus laevis 13S condensin complex, the Aspergillus BimD and Sordaria macrospora Spo76p proteins, the budding yeast Scc2p protein, and the related Drosophila transcriptional activator Nipped-B. Clathrin adaptor and COP-I coatomer subunits, which function in vesicle coat assembly and were previously noted to share weak sequence similarity to condensin subunits, also contain HEAT repeats. HEAT repeats were also found in the TBP-associated TIP120 protein, a global enhancer of transcription, and in the budding yeast Mot1p protein, which is a member of the SWI2/SNF2 family. SWI2/SNF2 proteins, some of which are helicases, perform diverse roles in transcription control, DNA repair, and chromosome segregation and form chromatin-remodeling complexes. HEAT repeats also were found in dis1-TOG family and cofactor D family microtubule-associated proteins, which, owing to their roles in microtubule dynamics, perform functions related to mitotic progression and chromosome segregation. Hence, our analysis predicts structural features of these proteins and suggests that HEAT repeats may play important roles in chromosome dynamics.
Collapse
Affiliation(s)
- A F Neuwald
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724,
| | | |
Collapse
|