1
|
Pla-Prats C, Thomä NH. Quality control of protein complex assembly by the ubiquitin-proteasome system. Trends Cell Biol 2022; 32:696-706. [PMID: 35300891 DOI: 10.1016/j.tcb.2022.02.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 12/12/2022]
Abstract
The majority of human proteins operate as multimeric complexes with defined compositions and distinct architectures. How the assembly of these complexes is surveyed and how defective complexes are recognized is just beginning to emerge. In eukaryotes, over 600 E3 ubiquitin ligases form part of the ubiquitin-proteasome system (UPS) which detects structural characteristics in its target proteins and selectively induces their degradation. The UPS has recently been shown to oversee key quality control steps during the assembly of protein complexes. We review recent findings on how E3 ubiquitin ligases regulate protein complex assembly and highlight unanswered questions relating to their mechanism of action.
Collapse
Affiliation(s)
- Carlos Pla-Prats
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; Faculty of Science, University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Nicolas H Thomä
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
| |
Collapse
|
2
|
Abstract
Microbes are hardly seen as planktonic species and are most commonly found as biofilm communities in cases of chronic infections. Biofilms are regarded as a biological condition, where a large group of microorganisms gets adhered to a biotic or abiotic surface. In this context, Pseudomonas aeruginosa, a Gram-negative nosocomial pathogen is the main causative organism responsible for life-threatening and persistent infections in individuals affected with cystic fibrosis and other lung ailments. The bacteria can form a strong biofilm structure when it adheres to a surface suitable for the development of a biofilm matrix. These bacterial biofilms pose higher natural resistance to conventional antibiotic therapy due to their multiple tolerance mechanisms. This prevailing condition has led to an increasing rate of treatment failures associated with P. aeruginosa biofilm infections. A better understanding of the effect of a diverse group of antibiotics on established biofilms would be necessary to avoid inappropriate treatment strategies. Hence, the search for other alternative strategies as effective biofilm treatment options has become a growing area of research. The current review aims to give an overview of the mechanisms governing biofilm formation and the different strategies employed so far in the control of biofilm infections caused by P. aeruginosa. Moreover, this review can also help researchers to search for new antibiofilm agents to tackle the effect of biofilm infections that are currently imprudent to conventional antibiotics.
Collapse
|
3
|
Yeo HK, Park TH, Kim HY, Jang H, Lee J, Hwang GS, Ryu SE, Park SH, Song HK, Ban HS, Yoon HJ, Lee BI. Phospholipid transfer function of PTPIP51 at mitochondria-associated ER membranes. EMBO Rep 2021; 22:e51323. [PMID: 33938112 DOI: 10.15252/embr.202051323] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 02/24/2021] [Accepted: 03/22/2021] [Indexed: 01/08/2023] Open
Abstract
In eukaryotic cells, mitochondria are closely tethered to the endoplasmic reticulum (ER) at sites called mitochondria-associated ER membranes (MAMs). Ca2+ ion and phospholipid transfer occurs at MAMs to support diverse cellular functions. Unlike those in yeast, the protein complexes involved in phospholipid transfer at MAMs in humans have not been identified. Here, we determine the crystal structure of the tetratricopeptide repeat domain of PTPIP51 (PTPIP51_TPR), a mitochondrial protein that interacts with the ER-anchored VAPB protein at MAMs. The structure of PTPIP51_TPR shows an archetypal TPR fold, and an electron density map corresponding to an unidentified lipid-like molecule probably derived from the protein expression host is found in the structure. We reveal functions of PTPIP51 in phospholipid binding/transfer, particularly of phosphatidic acid, in vitro. Depletion of PTPIP51 in cells reduces the mitochondrial cardiolipin level. Additionally, we confirm that the PTPIP51-VAPB interaction is mediated by the FFAT-like motif of PTPIP51 and the MSP domain of VAPB. Our findings suggest that PTPIP51 is a phospholipid transfer protein with a MAM-tethering function.
Collapse
Affiliation(s)
- Hyun Ku Yeo
- Research Institute, National Cancer Center, Goyang-si, Korea
| | - Tae Hyun Park
- Research Institute, National Cancer Center, Goyang-si, Korea.,Department of Bioengineering, Hanyang University, Seoul, Korea
| | - Hee Yeon Kim
- Research Institute, National Cancer Center, Goyang-si, Korea
| | - Hyonchol Jang
- Research Institute, National Cancer Center, Goyang-si, Korea.,Department of Cancer Biomedical Science, National Cancer Center Graduate School of Cancer Science and Policy, Goyang-si, Korea
| | - Jueun Lee
- Integrated Metabolomics Research Group, Western Seoul Center, Korea Basic Science Institute, Seoul, Korea
| | - Geum-Sook Hwang
- Integrated Metabolomics Research Group, Western Seoul Center, Korea Basic Science Institute, Seoul, Korea.,Department of Chemistry and Nano Science, Ewha Womans University, Seoul, Korea
| | - Seong Eon Ryu
- Department of Bioengineering, Hanyang University, Seoul, Korea
| | - Si Hoon Park
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Hyun Kyu Song
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Hyun Seung Ban
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Hye-Jin Yoon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Byung Il Lee
- Research Institute, National Cancer Center, Goyang-si, Korea.,Department of Cancer Biomedical Science, National Cancer Center Graduate School of Cancer Science and Policy, Goyang-si, Korea
| |
Collapse
|
4
|
Mueller F, Friese A, Pathe C, da Silva RC, Rodriguez KB, Musacchio A, Bange T. Overlap of NatA and IAP substrates implicates N-terminal acetylation in protein stabilization. SCIENCE ADVANCES 2021; 7:7/3/eabc8590. [PMID: 33523899 PMCID: PMC7810383 DOI: 10.1126/sciadv.abc8590] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/24/2020] [Indexed: 05/15/2023]
Abstract
SMAC/DIABLO and HTRA2 are mitochondrial proteins whose amino-terminal sequences, known as inhibitor of apoptosis binding motifs (IBMs), bind and activate ubiquitin ligases known as inhibitor of apoptosis proteins (IAPs), unleashing a cell's apoptotic potential. IBMs comprise a four-residue, loose consensus sequence, and binding to IAPs requires an unmodified amino terminus. Closely related, IBM-like N termini are present in approximately 5% of human proteins. We show that suppression of the N-alpha-acetyltransferase NatA turns these cryptic IBM-like sequences into very efficient IAP binders in cell lysates and in vitro and ultimately triggers cellular apoptosis. Thus, amino-terminal acetylation of IBM-like motifs in NatA substrates shields them from IAPs. This previously unrecognized relationship suggests that amino-terminal acetylation is generally protective against protein degradation in human cells. It also identifies IAPs as agents of a general quality control mechanism targeting unacetylated rogues in metazoans.
Collapse
Affiliation(s)
- Franziska Mueller
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Alexandra Friese
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Claudio Pathe
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Richard Cardoso da Silva
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Kenny Bravo Rodriguez
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany.
- Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitaetsstrasse, 45141 Essen, Germany
| | - Tanja Bange
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany.
- Institute of Medical Psychology, Faculty of Medicine, LMU Munich
| |
Collapse
|
5
|
Gaynor AS, Chen W. Conditional Protein Rescue by Binding-Induced Protective Shielding. ACS Synth Biol 2020; 9:2639-2647. [PMID: 33025786 DOI: 10.1021/acssynbio.0c00367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthetic protein-level circuits offer an extra layer of cellular control on top of conventional gene-level circuits. Here, we describe a technology that allows conditional protein rescue (CPR) from proteasomal degradation using different protein inputs as masking agents. A target protein is fused to a degron tag and an affinity sensor domain. The use of nanobodies as the sensor domain offers a generalizable strategy to execute a wide range of protein-level circuits with ease. The utility of this new strategy was successfully demonstrated to distinguish cancer cells out of a healthy population using the HPV-specific E7 protein as a cellular marker. Because CPR can be programmed to execute more complex Boolean logic designs using cell-specific proteomes, this platform offers a highly modular and scalable framework for a wide range of applications based on synthetic protein circuits.
Collapse
Affiliation(s)
- Andrew S. Gaynor
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| |
Collapse
|
6
|
Melloy PG. The anaphase-promoting complex: A key mitotic regulator associated with somatic mutations occurring in cancer. Genes Chromosomes Cancer 2019; 59:189-202. [PMID: 31652364 DOI: 10.1002/gcc.22820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 10/18/2019] [Accepted: 10/22/2019] [Indexed: 12/14/2022] Open
Abstract
The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase that helps control chromosome separation and exit from mitosis in many different kinds of organisms, including yeast, flies, worms, and humans. This review represents a new perspective on the connection between APC/C subunit mutations and cancer. The complex nature of APC/C and limited mutation analysis of its subunits has made it difficult to determine the relationship of each subunit to cancer. In this work, cancer genomic data were examined to identify APC/C subunits with a greater than 5% alteration frequency in 11 representative cancers using the cBioPortal database. Using the Genetic Determinants of Cancer Patient Survival database, APC/C subunits were also studied and found to be significantly associated with poor patient prognosis in several cases. In comparing these two kinds of cancer genomics data to published large-scale genomic analyses looking for cancer driver genes, ANAPC1 and ANAPC3/CDC27 stood out as being represented in all three types of analyses. Seven other subunits were found to be associated both with >5% alteration frequency in certain cancers and being associated with an effect on cancer patient prognosis. The aim of this review is to provide new approaches for investigators conducting in vivo studies of APC/C subunits and cancer progression. In turn, a better understanding of these APC/C subunits and their role in different cancers will help scientists design drugs that are more precisely targeted to certain cancers, using APC/C mutation status as a biomarker.
Collapse
Affiliation(s)
- Patricia G Melloy
- Department of Biological and Allied Health Sciences, Fairleigh Dickinson University, Madison, New Jersey
| |
Collapse
|
7
|
Zhang B, Zhu L, Dai Y, Li H, Huang K, Luo Y, Xu W. An in vitro attempt at precision toxicology reveals the involvement of DNA methylation alteration in ochratoxin A-induced G0/G1 phase arrest. Epigenetics 2019; 15:199-214. [PMID: 31314649 DOI: 10.1080/15592294.2019.1644878] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Precision toxicology evaluates the toxicity of certain substances by isolating a small group of cells with a typical phenotype of interest followed by a single cell sequencing-based analysis. In this in vitro attempt, ochratoxin A (OTA), a typical mycotoxin and food contaminant, is found to induce G0/G1 phase cell cycle arrest in human renal proximal tubular HKC cells at a concentration of 20 μM after a 24h-treatment. A small number of G0/G1 phase HKC cells are evaluated in both the presence and absence of OTA. These cells are sorted with a flow cytometer and subjected to mRNA and DNA methylation sequencing using Smart-Seq2 and single-cell reduced-representation bisulfite sequencing (scRRBS) technology, respectively. Integrated analysis of the transcriptome and methylome profiles reveals that OTA causes abnormal expression of the essential genes that regulate G1/S phase transition, act as signal transductors in G1 DNA damage checkpoints, and associate with the anaphase-promoting complex/cyclosome. The alteration of their DNA methylation status is a significant underlying epigenetic mechanism. Furthermore, Notch signaling and Ras/MAPK/CREB pathways are found to be suppressed by OTA. This attempt at precision toxicology paves the way for a deeper understanding of OTA toxicity and provides an innovative strategy to researchers in the toxicology and pharmacology field.
Collapse
Affiliation(s)
- Boyang Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Liye Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Yaqi Dai
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Hongyu Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Kunlun Huang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing, China
| | - Yunbo Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing, China
| | - Wentao Xu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing, China
| |
Collapse
|
8
|
Perez-Riba A, Lowe AR, Main ERG, Itzhaki LS. Context-Dependent Energetics of Loop Extensions in a Family of Tandem-Repeat Proteins. Biophys J 2019; 114:2552-2562. [PMID: 29874606 PMCID: PMC6129472 DOI: 10.1016/j.bpj.2018.03.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/28/2018] [Accepted: 03/29/2018] [Indexed: 11/16/2022] Open
Abstract
Consensus-designed tetratricopeptide repeat proteins are highly stable, modular proteins that are strikingly amenable to rational engineering. They therefore have tremendous potential as building blocks for biomaterials and biomedicine. Here, we explore the possibility of extending the loops between repeats to enable further diversification, and we investigate how this modification affects stability and folding cooperativity. We find that extending a single loop by up to 25 residues does not disrupt the overall protein structure, but, strikingly, the effect on stability is highly context-dependent: in a two-repeat array, destabilization is relatively small and can be accounted for purely in entropic terms, whereas extending a loop in the middle of a large array is much more costly because of weakening of the interaction between the repeats. Our findings provide important and, to our knowledge, new insights that increase our understanding of the structure, folding, and function of natural repeat proteins and the design of artificial repeat proteins in biotechnology.
Collapse
Affiliation(s)
- Albert Perez-Riba
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Alan R Lowe
- London Centre for Nanotechnology, London, United Kingdom; Structural & Molecular Biology, University College London, London, United Kingdom; Department of Biological Sciences, Birkbeck College, University of London, London, United Kingdom
| | - Ewan R G Main
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.
| | - Laura S Itzhaki
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom.
| |
Collapse
|
9
|
Levasseur MD, Thomas C, Davies OR, Higgins JMG, Madgwick S. Aneuploidy in Oocytes Is Prevented by Sustained CDK1 Activity through Degron Masking in Cyclin B1. Dev Cell 2019; 48:672-684.e5. [PMID: 30745144 PMCID: PMC6416240 DOI: 10.1016/j.devcel.2019.01.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 10/22/2018] [Accepted: 12/29/2018] [Indexed: 01/10/2023]
Abstract
Successful mitosis requires that cyclin B1:CDK1 kinase activity remains high until chromosomes are correctly aligned on the mitotic spindle. It has therefore been unclear why, in mammalian oocyte meiosis, cyclin B1 destruction begins before chromosome alignment is complete. Here, we resolve this paradox and show that mouse oocytes exploit an imbalance in the ratio of cyclin B1 to CDK1 to control CDK1 activity; early cyclin B1 destruction reflects the loss of an excess of non-CDK1-bound cyclin B1 in late prometaphase, while CDK1-bound cyclin B1 is destroyed only during metaphase. The ordered destruction of the two forms of cyclin B1 is brought about by a previously unidentified motif that is accessible in free cyclin B1 but masked when cyclin B1 is in complex with CDK1. This protects the CDK1-bound fraction from destruction in prometaphase, ensuring a period of prolonged CDK1 activity sufficient to achieve optimal chromosome alignment and prevent aneuploidy. In mouse oocytes, an excess of cyclin B1 preserves CDK1 activity A motif in non-CDK1-bound cyclin B1 confers preferential APC/C targeting Non-CDK1-bound cyclin B1 is gradually destroyed before CDK1-bound cyclin B1 Prolonged CDK1 activity assists the spindle checkpoint and prevents aneuploidy
Collapse
Affiliation(s)
- Mark D Levasseur
- Cell Division Biology Group, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Christopher Thomas
- Cell Division Biology Group, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Owen R Davies
- Cell Division Biology Group, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Jonathan M G Higgins
- Cell Division Biology Group, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Suzanne Madgwick
- Cell Division Biology Group, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
| |
Collapse
|
10
|
Watson ER, Brown NG, Peters JM, Stark H, Schulman BA. Posing the APC/C E3 Ubiquitin Ligase to Orchestrate Cell Division. Trends Cell Biol 2018; 29:117-134. [PMID: 30482618 DOI: 10.1016/j.tcb.2018.09.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/23/2018] [Accepted: 09/25/2018] [Indexed: 01/01/2023]
Abstract
The anaphase promoting complex/cyclosome (APC/C) E3 ligase controls mitosis and nonmitotic pathways through interactions with proteins that coordinate ubiquitylation. Since the discovery that the catalytic subunits of APC/C are conformationally dynamic cullin and RING proteins, many unexpected and intricate regulatory mechanisms have emerged. Here, we review structural knowledge of this regulation, focusing on: (i) coactivators, E2 ubiquitin (Ub)-conjugating enzymes, and inhibitors engage or influence multiple sites on APC/C including the cullin-RING catalytic core; and (ii) the outcomes of these interactions rely on mobility of coactivators and cullin-RING domains, which permits distinct conformations specifying different functions. Thus, APC/C is not simply an interaction hub, but is instead a dynamic, multifunctional molecular machine whose structure is remodeled by binding partners to achieve temporal ubiquitylation regulating cell division.
Collapse
Affiliation(s)
- Edmond R Watson
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany
| | - Nicholas G Brown
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Campus Vienna Biocenter (VBC) 1, 1030 Vienna, Austria
| | - Holger Stark
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany; Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| |
Collapse
|
11
|
Pivovarova Y, Liu J, Lesigang J, Koldyka O, Rauschmeier R, Hu K, Dong G. Structure of a Novel Dimeric SET Domain Methyltransferase that Regulates Cell Motility. J Mol Biol 2018; 430:4209-4229. [PMID: 30148980 PMCID: PMC7141177 DOI: 10.1016/j.jmb.2018.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/17/2018] [Accepted: 08/21/2018] [Indexed: 11/21/2022]
Abstract
Lysine methyltransferases (KMTs) were initially associated with transcriptional control through their methylation of histones and other nuclear proteins, but have since been found to regulate many other cellular activities. The apical complex lysine (K) methyltransferase (AKMT) of the human parasite Toxoplasma gondii was recently shown to play a critical role in regulating cellular motility. Here we report a 2.1-Å resolution crystal structure of the conserved and functional C-terminal portion (aa289-709) of T. gondii AKMT. AKMT dimerizes via a unique intermolecular interface mediated by the C-terminal tetratricopeptide repeat-like domain together with a specific zinc-binding motif that is absent from all other KMTs. Disruption of AKMT dimerization impaired both its enzyme activity and parasite egress from infected host cells in vivo. Structural comparisons reveal that AKMT is related to the KMTs in the SMYD family, with, however, a number of distinct structural features in addition to the unusual dimerization interface. These features are conserved among the apicomplexan parasites and their free-living relatives, but not found in any known KMTs in animals. AKMT therefore is the founding member of a new subclass of KMT that has important implications for the evolution of the apicomplexans.
Collapse
Affiliation(s)
- Yulia Pivovarova
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Jun Liu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Johannes Lesigang
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | | | - Rene Rauschmeier
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Ke Hu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
| | - Gang Dong
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
| |
Collapse
|
12
|
Paf1 and Ctr9 subcomplex formation is essential for Paf1 complex assembly and functional regulation. Nat Commun 2018; 9:3795. [PMID: 30228257 PMCID: PMC6143631 DOI: 10.1038/s41467-018-06237-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 08/15/2018] [Indexed: 11/09/2022] Open
Abstract
The evolutionarily conserved multifunctional polymerase-associated factor 1 (Paf1) complex (Paf1C), which is composed of at least five subunits (Paf1, Leo1, Ctr9, Cdc73, and Rtf1), plays vital roles in gene regulation and has connections to development and human diseases. Here, we report two structures of each of the human and yeast Ctr9/Paf1 subcomplexes, which assemble into heterodimers with very similar conformations, revealing an interface between the tetratricopeptide repeat module in Ctr9 and Paf1. The structure of the Ctr9/Paf1 subcomplex may provide mechanistic explanations for disease-associated mutations in human PAF1 and CTR9. Our study reveals that the formation of the Ctr9/Paf1 heterodimer is required for the assembly of yeast Paf1C, and is essential for yeast viability. In addition, disruption of the interaction between Paf1 and Ctr9 greatly affects the level of histone H3 methylation in vivo. Collectively, our results shed light on Paf1C assembly and functional regulation.
Collapse
|
13
|
Nguyen KT, Mun SH, Lee CS, Hwang CS. Control of protein degradation by N-terminal acetylation and the N-end rule pathway. Exp Mol Med 2018; 50:1-8. [PMID: 30054456 PMCID: PMC6063864 DOI: 10.1038/s12276-018-0097-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 04/11/2018] [Indexed: 11/10/2022] Open
Abstract
Nα-terminal acetylation (Nt-acetylation) occurs very frequently and is found in most proteins in eukaryotes. Despite the pervasiveness and universality of Nt-acetylation, its general functions in terms of physiological outcomes remain largely elusive. However, several recent studies have revealed that Nt-acetylation has a significant impact on protein stability, activity, folding patterns, cellular localization, etc. In addition, Nt-acetylation marks specific proteins for degradation by a branch of the N-end rule pathway, a subset of the ubiquitin-mediated proteolytic system. The N-end rule associates a protein's in vivo half-life with its N-terminal residue or modifications on its N-terminus. This review provides a current understanding of intracellular proteolysis control by Nt-acetylation and the N-end rule pathway.
Collapse
Affiliation(s)
- Kha The Nguyen
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Sang-Hyeon Mun
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Chang-Seok Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea.
| |
Collapse
|
14
|
Molecular basis of GID4-mediated recognition of degrons for the Pro/N-end rule pathway. Nat Chem Biol 2018; 14:466-473. [DOI: 10.1038/s41589-018-0036-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/22/2018] [Indexed: 11/08/2022]
|
15
|
Abstract
Asymmetric cell divisions balance stem cell proliferation and differentiation to sustain tissue morphogenesis and homeostasis. During asymmetric divisions, fate determinants and niche contacts segregate unequally between daughters, but little is known on how this is achieved mechanistically. In Drosophila neuroblasts and murine mammary stem cells, the association of the spindle orientation protein LGN with the stem cell adaptor Inscuteable has been connected to asymmetry. Here we report the crystal structure of Drosophila LGN in complex with the asymmetric domain of Inscuteable, which reveals a tetrameric arrangement of intertwined molecules. We show that Insc:LGN tetramers constitute stable cores of Par3–Insc-LGN-GαiGDP complexes, which cannot be dissociated by NuMA. In mammary stem cells, the asymmetric domain of Insc bound to LGN:GαiGDP suffices to drive asymmetric fate, and reverts aberrant symmetric divisions induced by p53 loss. We suggest a novel role for the Insc-bound pool of LGN acting independently of microtubule motors to promote asymmetric fate specification. During asymmetric divisions fate determinants and niche contacts segregate unequally between daughter cells, but the mechanism is unclear. Here the authors show that Insc:LGN tetramers promote assembly of Par3-Insc-LGN-GαiGDP complexes and asymmetric fate specification independently of microtubule motors.
Collapse
|
16
|
Peterson LX, Shin WH, Kim H, Kihara D. Improved performance in CAPRI round 37 using LZerD docking and template-based modeling with combined scoring functions. Proteins 2018; 86 Suppl 1:311-320. [PMID: 28845596 PMCID: PMC5820220 DOI: 10.1002/prot.25376] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/09/2017] [Accepted: 08/24/2017] [Indexed: 12/12/2022]
Abstract
We report our group's performance for protein-protein complex structure prediction and scoring in Round 37 of the Critical Assessment of PRediction of Interactions (CAPRI), an objective assessment of protein-protein complex modeling. We demonstrated noticeable improvement in both prediction and scoring compared to previous rounds of CAPRI, with our human predictor group near the top of the rankings and our server scorer group at the top. This is the first time in CAPRI that a server has been the top scorer group. To predict protein-protein complex structures, we used both multi-chain template-based modeling (TBM) and our protein-protein docking program, LZerD. LZerD represents protein surfaces using 3D Zernike descriptors (3DZD), which are based on a mathematical series expansion of a 3D function. Because 3DZD are a soft representation of the protein surface, LZerD is tolerant to small conformational changes, making it well suited to docking unbound and TBM structures. The key to our improved performance in CAPRI Round 37 was to combine multi-chain TBM and docking. As opposed to our previous strategy of performing docking for all target complexes, we used TBM when multi-chain templates were available and docking otherwise. We also describe the combination of multiple scoring functions used by our server scorer group, which achieved the top rank for the scorer phase.
Collapse
Affiliation(s)
- Lenna X. Peterson
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Woong-Hee Shin
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Hyungrae Kim
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Daisuke Kihara
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
- Department of Computer Science, Purdue University, West Lafayette, IN, 47907, USA
| |
Collapse
|
17
|
Croft T, James Theoga Raj C, Salemi M, Phinney BS, Lin SJ. A functional link between NAD + homeostasis and N-terminal protein acetylation in Saccharomyces cerevisiae. J Biol Chem 2018; 293:2927-2938. [PMID: 29317496 DOI: 10.1074/jbc.m117.807214] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 12/15/2017] [Indexed: 12/12/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite participating in cellular redox chemistry and signaling, and the complex regulation of NAD+ metabolism is not yet fully understood. To investigate this, we established a NAD+-intermediate specific reporter system to identify factors required for salvage of metabolically linked nicotinamide (NAM) and nicotinic acid (NA). Mutants lacking components of the NatB complex, NAT3 and MDM20, appeared as hits in this screen. NatB is an Nα-terminal acetyltransferase responsible for acetylation of the N terminus of specific Met-retained peptides. In NatB mutants, increased NA/NAM levels were concomitant with decreased NAD+ We identified the vacuolar pool of nicotinamide riboside (NR) as the source of this increased NA/NAM. This NR pool is increased by nitrogen starvation, suggesting NAD+ and related metabolites may be trafficked to the vacuole for recycling. Supporting this, increased NA/NAM release in NatB mutants was abolished by deleting the autophagy protein ATG14 We next examined Tpm1 (tropomyosin), whose function is regulated by NatB-mediated acetylation, and Tpm1 overexpression (TPM1-oe) was shown to restore some NatB mutant defects. Interestingly, although TPM1-oe largely suppressed NA/NAM release in NatB mutants, it did not restore NAD+ levels. We showed that decreased nicotinamide mononucleotide adenylyltransferase (Nma1/Nma2) levels probably caused the NAD+ defects, and NMA1-oe was sufficient to restore NAD+ NatB-mediated N-terminal acetylation of Nma1 and Nma2 appears essential for maintaining NAD+ levels. In summary, our results support a connection between NatB-mediated protein acetylation and NAD+ homeostasis. Our findings may contribute to understanding the molecular basis and regulation of NAD+ metabolism.
Collapse
Affiliation(s)
- Trevor Croft
- Department of Microbiology and Molecular Genetics, College of Biological Sciences
| | | | - Michelle Salemi
- Proteomic Core Facility, University of California, Davis, California 95616
| | - Brett S Phinney
- Proteomic Core Facility, University of California, Davis, California 95616
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences.
| |
Collapse
|
18
|
Alfieri C, Zhang S, Barford D. Visualizing the complex functions and mechanisms of the anaphase promoting complex/cyclosome (APC/C). Open Biol 2017; 7:170204. [PMID: 29167309 PMCID: PMC5717348 DOI: 10.1098/rsob.170204] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/10/2017] [Indexed: 12/17/2022] Open
Abstract
The anaphase promoting complex or cyclosome (APC/C) is a large multi-subunit E3 ubiquitin ligase that orchestrates cell cycle progression by mediating the degradation of important cell cycle regulators. During the two decades since its discovery, much has been learnt concerning its role in recognizing and ubiquitinating specific proteins in a cell-cycle-dependent manner, the mechanisms governing substrate specificity, the catalytic process of assembling polyubiquitin chains on its target proteins, and its regulation by phosphorylation and the spindle assembly checkpoint. The past few years have witnessed significant progress in understanding the quantitative mechanisms underlying these varied APC/C functions. This review integrates the overall functions and properties of the APC/C with mechanistic insights gained from recent cryo-electron microscopy (cryo-EM) studies of reconstituted human APC/C complexes.
Collapse
Affiliation(s)
- Claudio Alfieri
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Suyang Zhang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - David Barford
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| |
Collapse
|
19
|
Magin RS, Deng S, Zhang H, Cooperman B, Marmorstein R. Probing the interaction between NatA and the ribosome for co-translational protein acetylation. PLoS One 2017; 12:e0186278. [PMID: 29016658 PMCID: PMC5634638 DOI: 10.1371/journal.pone.0186278] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/28/2017] [Indexed: 01/02/2023] Open
Abstract
N-terminal acetylation is among the most abundant protein modifications in eukaryotic cells. Over the last decade, significant progress has been made in elucidating the function of N-terminal acetylation for a number of diverse systems, involved in a wide variety of biological processes. The enzymes responsible for the modification are the N-terminal acetyltransferases (NATs). The NATs are a highly conserved group of enzymes in eukaryotes, which are responsible for acetylating over 80% of the soluble proteome in human cells. Importantly, many of these NATs act co-translationally; they interact with the ribosome near the exit tunnel and acetylate the nascent protein chain as it is being translated. While the structures of many of the NATs have been determined, the molecular basis for the interaction with ribosome is not known. Here, using purified ribosomes and NatA, a very well-studied NAT, we show that NatA forms a stable complex with the ribosome in the absence of other stabilizing factors and through two conserved regions; primarily through an N-terminal domain and an internal basic helix. These regions may orient the active site of the NatA to face the peptide emerging from the exit tunnel. This work provides a framework for understanding how NatA and potentially other NATs interact with the ribosome for co-translational protein acetylation and sets the foundation for future studies to decouple N-terminal acetyltransferase activity from ribosome association.
Collapse
Affiliation(s)
- Robert S. Magin
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Graduate Group in Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sunbin Deng
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Haibo Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Barry Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ronen Marmorstein
- Department of Biochemistry and Biophysics, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| |
Collapse
|
20
|
Bakkum AL, Hill RB. Removal of a consensus proline is not sufficient to allow tetratricopeptide repeat oligomerization. Protein Sci 2017; 26:1974-1983. [PMID: 28707340 DOI: 10.1002/pro.3234] [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] [Received: 05/17/2017] [Revised: 07/07/2017] [Accepted: 07/07/2017] [Indexed: 11/10/2022]
Abstract
Tetratricopeptide repeat (TPR) domains are ubiquitous protein interaction domains that adopt a modular antiparallel array of α-helices. The TPR fold typically adopts a monomeric state, and consensus TPRs sequences successfully fold into the expected monomeric topology. The versatility of the TPR fold also supports different quaternary structures, which may function as regulatory switches. One example is yeast mitochondrial fission 1 (Fis1) that appears to interconvert between monomer and dimer states in regulating division of peroxisomes and mitochondria. Whether human Fis1 can also interconvert like the yeast molecule is unknown. A TPR consensus proline residue present in human Fis1 is absent in the yeast molecule and, when added, prevents yeast Fis1 dimerization suggesting that the TPR consensus proline might have persisted to prevent TPR oligomerization. Here, we address this question with human Fis1 and the consensus TPR protein CTPR3. We demonstrate that human Fis1 does not form a noncovalent dimer via its TPR domain, despite conditions that favor dimerization of the yeast protein. We also show that the presence of the consensus proline is not sufficient to forbid TPR dimerization. Lastly, an analysis of all available TPR protein structures (22 nonredundant structures, totaling 64 TPRs-42 with the consensus proline and 22 without) revealed that the consensus proline is not necessary for turn formation, but does favor shorter turns. This work suggests the TPR consensus proline is not to prevent oligomerization, but to favor tight turns between repeats.
Collapse
Affiliation(s)
- Amber L Bakkum
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226
| | - R Blake Hill
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226
| |
Collapse
|
21
|
Scott DC, Hammill JT, Min J, Rhee DY, Connelly M, Sviderskiy VO, Bhasin D, Chen Y, Ong SS, Chai SC, Goktug AN, Huang G, Monda JK, Low J, Kim HS, Paulo JA, Cannon JR, Shelat AA, Chen T, Kelsall IR, Alpi AF, Pagala V, Wang X, Peng J, Singh B, Harper JW, Schulman BA, Guy RK. Blocking an N-terminal acetylation-dependent protein interaction inhibits an E3 ligase. Nat Chem Biol 2017; 13:850-857. [PMID: 28581483 PMCID: PMC5577376 DOI: 10.1038/nchembio.2386] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 04/07/2017] [Indexed: 12/25/2022]
Abstract
N-terminal acetylation is an abundant modification influencing protein functions. Since ≈80% of mammalian cytosolic proteins are N-terminally acetylated, this potentially represents an untapped target for chemical control of their functions. Structural studies have revealed that, like lysine acetylation, N-terminal acetylation converts a positively charged amine into a hydrophobic handle that mediates protein interactions, suggesting it may be a druggable target. We report the development of chemical probes targeting the N-terminal acetylation-dependent interaction between an E2 conjugating enzyme (UBE2M, aka UBC12) and DCN1 (aka DCUN1D1), a subunit of a multiprotein E3 ligase for the ubiquitin-like protein NEDD8. The inhibitors are highly selective with respect to other protein acetyl amide binding sites, inhibit NEDD8 ligation in vitro and in cells, and suppress the anchorage-independent growth of a cell line harboring DCN1 amplification. Overall, the data demonstrate that N-terminal acetyl-dependent protein interactions are druggable targets, and provide insights into targeting multiprotein E2–E3 ligases.
Collapse
Affiliation(s)
- Daniel C Scott
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.,Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jared T Hammill
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jaeki Min
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - David Y Rhee
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Michele Connelly
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Vladislav O Sviderskiy
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Deepak Bhasin
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Yizhe Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Su-Sien Ong
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Sergio C Chai
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Asli N Goktug
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Guochang Huang
- Laboratory of Epithelial Cancer Biology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
| | - Julie K Monda
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jonathan Low
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Ho Shin Kim
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Joe R Cannon
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Anang A Shelat
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Ian R Kelsall
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Arno F Alpi
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Vishwajeeth Pagala
- St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Xusheng Wang
- St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Junmin Peng
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.,St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Bhuvanesh Singh
- Laboratory of Epithelial Cancer Biology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Brenda A Schulman
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.,Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - R Kip Guy
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| |
Collapse
|
22
|
Control of Hsp90 chaperone and its clients by N-terminal acetylation and the N-end rule pathway. Proc Natl Acad Sci U S A 2017; 114:E4370-E4379. [PMID: 28515311 DOI: 10.1073/pnas.1705898114] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We found that the heat shock protein 90 (Hsp90) chaperone system of the yeast Saccharomyces cerevisiae is greatly impaired in naa10Δ cells, which lack the NatA Nα-terminal acetylase (Nt-acetylase) and therefore cannot N-terminally acetylate a majority of normally N-terminally acetylated proteins, including Hsp90 and most of its cochaperones. Chk1, a mitotic checkpoint kinase and a client of Hsp90, was degraded relatively slowly in wild-type cells but was rapidly destroyed in naa10Δ cells by the Arg/N-end rule pathway, which recognized a C terminus-proximal degron of Chk1. Diverse proteins (in addition to Chk1) that are shown here to be targeted for degradation by the Arg/N-end rule pathway in naa10Δ cells include Kar4, Tup1, Gpd1, Ste11, and also, remarkably, the main Hsp90 chaperone (Hsc82) itself. Protection of Chk1 by Hsp90 could be overridden not only by ablation of the NatA Nt-acetylase but also by overexpression of the Arg/N-end rule pathway in wild-type cells. Split ubiquitin-binding assays detected interactions between Hsp90 and Chk1 in wild-type cells but not in naa10Δ cells. These and related results revealed a major role of Nt-acetylation in the Hsp90-mediated protein homeostasis, a strong up-regulation of the Arg/N-end rule pathway in the absence of NatA, and showed that a number of Hsp90 clients are previously unknown substrates of the Arg/N-end rule pathway.
Collapse
|
23
|
Zhu H, Sepulveda E, Hartmann MD, Kogenaru M, Ursinus A, Sulz E, Albrecht R, Coles M, Martin J, Lupas AN. Origin of a folded repeat protein from an intrinsically disordered ancestor. eLife 2016; 5:e16761. [PMID: 27623012 PMCID: PMC5074805 DOI: 10.7554/elife.16761] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 09/09/2016] [Indexed: 01/03/2023] Open
Abstract
Repetitive proteins are thought to have arisen through the amplification of subdomain-sized peptides. Many of these originated in a non-repetitive context as cofactors of RNA-based replication and catalysis, and required the RNA to assume their active conformation. In search of the origins of one of the most widespread repeat protein families, the tetratricopeptide repeat (TPR), we identified several potential homologs of its repeated helical hairpin in non-repetitive proteins, including the putatively ancient ribosomal protein S20 (RPS20), which only becomes structured in the context of the ribosome. We evaluated the ability of the RPS20 hairpin to form a TPR fold by amplification and obtained structures identical to natural TPRs for variants with 2-5 point mutations per repeat. The mutations were neutral in the parent organism, suggesting that they could have been sampled in the course of evolution. TPRs could thus have plausibly arisen by amplification from an ancestral helical hairpin.
Collapse
Affiliation(s)
- Hongbo Zhu
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Edgardo Sepulveda
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Marcus D Hartmann
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Manjunatha Kogenaru
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Astrid Ursinus
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Eva Sulz
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Reinhard Albrecht
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Murray Coles
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Jörg Martin
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Andrei N Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| |
Collapse
|
24
|
Aksnes H, Drazic A, Marie M, Arnesen T. First Things First: Vital Protein Marks by N-Terminal Acetyltransferases. Trends Biochem Sci 2016; 41:746-760. [PMID: 27498224 DOI: 10.1016/j.tibs.2016.07.005] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 07/01/2016] [Accepted: 07/08/2016] [Indexed: 11/28/2022]
Abstract
N-terminal (Nt) acetylation is known to be a highly abundant co-translational protein modification, but the recent discovery of Golgi- and chloroplast-resident N-terminal acetyltransferases (NATs) revealed that it can also be added post-translationally. Nt-acetylation may act as a degradation signal in a novel branch of the N-end rule pathway, whose functions include the regulation of human blood pressure. Nt-acetylation also modulates protein interactions, targeting, and folding. In plants, Nt-acetylation plays a role in the control of resistance to drought and in regulation of immune responses. Mutations of specific human NATs that decrease their activity can cause either the lethal Ogden syndrome or severe intellectual disability and cardiovascular defects. In sum, recent advances highlight Nt-acetylation as a key factor in many biological pathways.
Collapse
Affiliation(s)
- Henriette Aksnes
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Adrian Drazic
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Michaël Marie
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Thomas Arnesen
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway; Department of Surgery, Haukeland University Hospital, 5021 Bergen, Norway.
| |
Collapse
|
25
|
Lee KE, Heo JE, Kim JM, Hwang CS. N-Terminal Acetylation-Targeted N-End Rule Proteolytic System: The Ac/N-End Rule Pathway. Mol Cells 2016; 39:169-78. [PMID: 26883906 PMCID: PMC4794598 DOI: 10.14348/molcells.2016.2329] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/11/2016] [Accepted: 01/14/2016] [Indexed: 12/12/2022] Open
Abstract
Although Nα-terminal acetylation (Nt-acetylation) is a pervasive protein modification in eukaryotes, its general functions in a majority of proteins are poorly understood. In 2010, it was discovered that Nt-acetylation creates a specific protein degradation signal that is targeted by a new class of the N-end rule proteolytic system, called the Ac/N-end rule pathway. Here, we review recent advances in our understanding of the mechanism and biological functions of the Ac/N-end rule pathway, and its crosstalk with the Arg/N-end rule pathway (the classical N-end rule pathway).
Collapse
Affiliation(s)
- Kang-Eun Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Ji-Eun Heo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Jeong-Mok Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| |
Collapse
|
26
|
Zhang Z, Yang J, Barford D. Recombinant expression and reconstitution of multiprotein complexes by the USER cloning method in the insect cell-baculovirus expression system. Methods 2016; 95:13-25. [PMID: 26454197 DOI: 10.1016/j.ymeth.2015.10.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/03/2015] [Accepted: 10/05/2015] [Indexed: 01/02/2023] Open
Abstract
The capacity to reconstitute complex biological processes in vitro is a crucial step in providing a quantitative understanding of these systems. It provides material for structural, biochemical and biophysical analyses and allows the testing of biological hypotheses and the introduction of chemical probes and tags for single molecule analysis. Reconstitution of these systems requires access to homogenous components, usually through their over-production in heterologous over-expression systems. Here we describe the application of the USER (Uracil-Specific Excision Reagent) ligation-free cloning method to assemble recombinant MultiBac transfer vectors for the generation of recombinant baculovirus suitable for the expression of multi-protein complexes in insect cells.
Collapse
Affiliation(s)
- Ziguo Zhang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Jing Yang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - David Barford
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
| |
Collapse
|
27
|
Piatkov KI, Vu TTM, Hwang CS, Varshavsky A. Formyl-methionine as a degradation signal at the N-termini of bacterial proteins. MICROBIAL CELL (GRAZ, AUSTRIA) 2016; 2:376-393. [PMID: 26866044 PMCID: PMC4745127 DOI: 10.15698/mic2015.10.231] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 08/17/2015] [Indexed: 02/04/2023]
Abstract
In bacteria, all nascent proteins bear the pretranslationally formed N-terminal formyl-methionine (fMet) residue. The fMet residue is cotranslationally deformylated by a ribosome-associated deformylase. The formylation of N-terminal Met in bacterial proteins is not strictly essential for either translation or cell viability. Moreover, protein synthesis by the cytosolic ribosomes of eukaryotes does not involve the formylation of N-terminal Met. What, then, is the main biological function of this metabolically costly, transient, and not strictly essential modification of N-terminal Met, and why has Met formylation not been eliminated during bacterial evolution? One possibility is that the similarity of the formyl and acetyl groups, their identical locations in N-terminally formylated (Nt-formylated) and Nt-acetylated proteins, and the recently discovered proteolytic function of Nt-acetylation in eukaryotes might also signify a proteolytic role of Nt-formylation in bacteria. We addressed this hypothesis about fMet-based degradation signals, termed fMet/N-degrons, using specific E. coli mutants, pulse-chase degradation assays, and protein reporters whose deformylation was altered, through site-directed mutagenesis, to be either rapid or relatively slow. Our findings strongly suggest that the formylated N-terminal fMet can act as a degradation signal, largely a cotranslational one. One likely function of fMet/N-degrons is the control of protein quality. In bacteria, the rate of polypeptide chain elongation is nearly an order of magnitude higher than in eukaryotes. We suggest that the faster emergence of nascent proteins from bacterial ribosomes is one mechanistic and evolutionary reason for the pretranslational design of bacterial fMet/N-degrons, in contrast to the cotranslational design of analogous Ac/N-degrons in eukaryotes.
Collapse
Affiliation(s)
- Konstantin I. Piatkov
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
- Center for Biotechnology and Biomedicine, Skolkovo Institute of Science and Technology, Moscow, 143026, Russia
| | - Tri T. M. Vu
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 790-784, South Korea
| | - Alexander Varshavsky
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| |
Collapse
|
28
|
Cifuentes M, Jolivet S, Cromer L, Harashima H, Bulankova P, Renne C, Crismani W, Nomura Y, Nakagami H, Sugimoto K, Schnittger A, Riha K, Mercier R. TDM1 Regulation Determines the Number of Meiotic Divisions. PLoS Genet 2016; 12:e1005856. [PMID: 26871453 PMCID: PMC4752240 DOI: 10.1371/journal.pgen.1005856] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 01/20/2016] [Indexed: 11/18/2022] Open
Abstract
Cell cycle control must be modified at meiosis to allow two divisions to follow a single round of DNA replication, resulting in ploidy reduction. The mechanisms that ensure meiosis termination at the end of the second and not at the end of first division are poorly understood. We show here that Arabidopsis thaliana TDM1, which has been previously shown to be essential for meiotic termination, interacts directly with the Anaphase-Promoting Complex. Further, mutations in TDM1 in a conserved putative Cyclin-Dependant Kinase (CDK) phosphorylation site (T16-P17) dominantly provoked premature meiosis termination after the first division, and the production of diploid spores and gametes. The CDKA;1-CYCA1.2/TAM complex, which is required to prevent premature meiotic exit, phosphorylated TDM1 at T16 in vitro. Finally, while CYCA1;2/TAM was previously shown to be expressed only at meiosis I, TDM1 is present throughout meiosis. These data, together with epistasis analysis, lead us to propose that TDM1 is an APC/C component whose function is to ensure meiosis termination at the end of meiosis II, and whose activity is inhibited at meiosis I by CDKA;1-TAM-mediated phosphorylation to prevent premature meiotic exit. This provides a molecular mechanism for the differential decision of performing an additional round of division, or not, at the end of meiosis I and II, respectively. Meiosis is a fundamental process for sexually reproducing organisms that creates genetic diversity within populations. A key feature of meiosis is the reduction of the number of chromosomes, from two sets to one set, prior to fertilization. This reduction in chromosome number is due to two cell divisions following a single round of DNA replication. In this study, we analysed the mechanism which controls the number of cell divisions, ensuring that meiotic termination occurs after the second meiotic division, and not at the end of the first division. We used the model plant Arabidopsis thaliana to show that the gene TDM1 has a central role in regulating meiotic cell divisions. The integrity of the gene affects whether one, two or three meiotic divisions will occur. We further explain the relationship between TDM1 and its regulator the cyclin TAM, and how they work together to produce reproductive cells with a reduced number of chromosomes. This tightly controlled mechanism ensures the transmission of the correct number of chromosomes from one generation to the next.
Collapse
Affiliation(s)
- Marta Cifuentes
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026 Versailles Cedex, France
| | - Sylvie Jolivet
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026 Versailles Cedex, France
| | - Laurence Cromer
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026 Versailles Cedex, France
| | - Hirofumi Harashima
- RIKEN Center for Sustainable Resource Science, Suehiro, Tsurumi, Yokohama, Japan
| | - Petra Bulankova
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna, Austria
| | - Charlotte Renne
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026 Versailles Cedex, France
| | - Wayne Crismani
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026 Versailles Cedex, France
| | - Yuko Nomura
- RIKEN Center for Sustainable Resource Science, Suehiro, Tsurumi, Yokohama, Japan
| | - Hirofumi Nakagami
- RIKEN Center for Sustainable Resource Science, Suehiro, Tsurumi, Yokohama, Japan
| | - Keiko Sugimoto
- RIKEN Center for Sustainable Resource Science, Suehiro, Tsurumi, Yokohama, Japan
| | - Arp Schnittger
- University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, Hamburg, Germany
| | - Karel Riha
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna, Austria
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice, Brno, Czech Republic
| | - Raphael Mercier
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026 Versailles Cedex, France
- * E-mail:
| |
Collapse
|
29
|
Cronin NB, Yang J, Zhang Z, Kulkarni K, Chang L, Yamano H, Barford D. Atomic-Resolution Structures of the APC/C Subunits Apc4 and the Apc5 N-Terminal Domain. J Mol Biol 2015; 427:3300-3315. [PMID: 26343760 PMCID: PMC4590430 DOI: 10.1016/j.jmb.2015.08.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/19/2015] [Accepted: 08/26/2015] [Indexed: 10/25/2022]
Abstract
Many essential biological processes are mediated by complex molecular machines comprising multiple subunits. Knowledge on the architecture of individual subunits and their positions within the overall multimeric complex is key to understanding the molecular mechanisms of macromolecular assemblies. The anaphase-promoting complex/cyclosome (APC/C) is a large multisubunit complex that regulates cell cycle progression by ubiquitinating cell cycle proteins for proteolysis by the proteasome. The holo-complex is composed of 15 different proteins that assemble to generate a complex of 20 subunits. Here, we describe the crystal structures of Apc4 and the N-terminal domain of Apc5 (Apc5(N)). Apc4 comprises a WD40 domain split by a long α-helical domain, whereas Apc5(N) has an α-helical fold. In a separate study, we had fitted these atomic models to a 3.6-Å-resolution cryo-electron microscopy map of the APC/C. We describe how, in the context of the APC/C, regions of Apc4 disordered in the crystal assume order through contacts to Apc5, whereas Apc5(N) shows small conformational changes relative to its crystal structure. We discuss the complementary approaches of high-resolution electron microscopy and protein crystallography to the structure determination of subunits of multimeric complexes.
Collapse
Affiliation(s)
- Nora B Cronin
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom
| | - Jing Yang
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Ziguo Zhang
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Kiran Kulkarni
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom; Division of Biochemical Sciences, Council of Scientific and Industrial Research National Chemical Laboratory, Pune 411008, India
| | - Leifu Chang
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Hiroyuki Yamano
- Cancer Institute, University College London, Paul O'Gorman Building, 72 Huntley Street, London WC1E 6BT, United Kingdom
| | - David Barford
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
| |
Collapse
|
30
|
Rahimi H, Ahmadzadeh A, Yousef-amoli S, Kokabee L, Shokrgozar MA, Mahdian R, Karimipoor M. The expression pattern of APC2 and APC7 in various cancer cell lines and AML patients. Adv Med Sci 2015; 60:259-63. [PMID: 26046517 DOI: 10.1016/j.advms.2015.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 03/11/2015] [Accepted: 04/30/2015] [Indexed: 01/29/2023]
Abstract
PURPOSE Anaphase promoting complex (APC/C) is an E3 ligase enzyme, which ubiquinates various proteins involved in the cell cycle. This protein complex may have a pivotal role in the cell cycle control affecting pathological conditions such as cancer. APC7 and APC2 subunits of the APC/C complex are involved in the substrate recognition and the catalytic reaction, respectively. MATERIALS AND METHODS In this study, quantitative Real-time PCR was used to analyse APC2 and APC7 expression in different cancer cell lines as well as AML patient's blood cells. RESULTS The results showed that APC2 and APC7 subunits were both over expressed in cancer cell lines (p=0.008). The mean expression ratio of APC2 and APC7 in different cancer cells were 2.60±0.22 and 4.83±0.11, respectively. An increase in expression of APC2 and APC7 was seen among 12 out of 14 AML patients (85%). There was a significant positive correlation between APC2 upregulation and the detection of splenomegaly in the patients (r=0.808, p=0.001). CONCLUSION This was the first study suggesting that APC/C upregulation may contribute to the pathogenesis of cancer and can be used as a molecular biomarker to predict the progression and the prognosis of AML.
Collapse
Affiliation(s)
- Hamzeh Rahimi
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Ahmad Ahmadzadeh
- Thalassemia and Hemoglobinopathy Research Center, Shafa Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Shamseddin Yousef-amoli
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Leila Kokabee
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | | | - Reza Mahdian
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
| | - Mortaza Karimipoor
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
| |
Collapse
|
31
|
Chang L, Zhang Z, Yang J, McLaughlin SH, Barford D. Atomic structure of the APC/C and its mechanism of protein ubiquitination. Nature 2015; 522:450-454. [PMID: 26083744 PMCID: PMC4608048 DOI: 10.1038/nature14471] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 04/10/2015] [Indexed: 12/12/2022]
Abstract
The anaphase-promoting complex (APC/C) is a multimeric RING E3 ubiquitin ligase that controls chromosome segregation and mitotic exit. Its regulation by coactivator subunits, phosphorylation, the mitotic checkpoint complex and interphase early mitotic inhibitor 1 (Emi1) ensures the correct order and timing of distinct cell-cycle transitions. Here we use cryo-electron microscopy to determine atomic structures of APC/C-coactivator complexes with either Emi1 or a UbcH10-ubiquitin conjugate. These structures define the architecture of all APC/C subunits, the position of the catalytic module and explain how Emi1 mediates inhibition of the two E2s UbcH10 and Ube2S. Definition of Cdh1 interactions with the APC/C indicates how they are antagonized by Cdh1 phosphorylation. The structure of the APC/C with UbcH10-ubiquitin reveals insights into the initiating ubiquitination reaction. Our results provide a quantitative framework for the design of future experiments to investigate APC/C functions in vivo.
Collapse
MESH Headings
- Anaphase-Promoting Complex-Cyclosome/chemistry
- Anaphase-Promoting Complex-Cyclosome/metabolism
- Anaphase-Promoting Complex-Cyclosome/ultrastructure
- Antigens, CD
- Apc1 Subunit, Anaphase-Promoting Complex-Cyclosome/chemistry
- Apc1 Subunit, Anaphase-Promoting Complex-Cyclosome/metabolism
- Apc1 Subunit, Anaphase-Promoting Complex-Cyclosome/ultrastructure
- Apc10 Subunit, Anaphase-Promoting Complex-Cyclosome/chemistry
- Apc10 Subunit, Anaphase-Promoting Complex-Cyclosome/metabolism
- Apc10 Subunit, Anaphase-Promoting Complex-Cyclosome/ultrastructure
- Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome/chemistry
- Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome/metabolism
- Apc3 Subunit, Anaphase-Promoting Complex-Cyclosome/chemistry
- Apc3 Subunit, Anaphase-Promoting Complex-Cyclosome/metabolism
- Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome/chemistry
- Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome/metabolism
- Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome/ultrastructure
- Cadherins/chemistry
- Cadherins/metabolism
- Cadherins/ultrastructure
- Catalytic Domain
- Cell Cycle Proteins/chemistry
- Cell Cycle Proteins/metabolism
- Cell Cycle Proteins/ultrastructure
- Cryoelectron Microscopy
- Cytoskeletal Proteins/chemistry
- Cytoskeletal Proteins/metabolism
- F-Box Proteins/chemistry
- F-Box Proteins/metabolism
- F-Box Proteins/ultrastructure
- Humans
- Lysine/metabolism
- Models, Molecular
- Phosphorylation
- Protein Binding
- Protein Subunits/chemistry
- Protein Subunits/metabolism
- Structure-Activity Relationship
- Substrate Specificity
- Ubiquitin/chemistry
- Ubiquitin/metabolism
- Ubiquitin/ultrastructure
- Ubiquitin-Conjugating Enzymes/chemistry
- Ubiquitin-Conjugating Enzymes/metabolism
- Ubiquitin-Conjugating Enzymes/ultrastructure
- Ubiquitination
Collapse
Affiliation(s)
- Leifu Chang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Ziguo Zhang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Jing Yang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Stephen H McLaughlin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - David Barford
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| |
Collapse
|
32
|
Sivakumar S, Gorbsky GJ. Spatiotemporal regulation of the anaphase-promoting complex in mitosis. Nat Rev Mol Cell Biol 2015; 16:82-94. [PMID: 25604195 DOI: 10.1038/nrm3934] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The appropriate timing of events that lead to chromosome segregation during mitosis and cytokinesis is essential to prevent aneuploidy, and defects in these processes can contribute to tumorigenesis. Key mitotic regulators are controlled through ubiquitylation and proteasome-mediated degradation. The APC/C (anaphase-promoting complex; also known as the cyclosome) is an E3 ubiquitin ligase that has a crucial function in the regulation of the mitotic cell cycle, particularly at the onset of anaphase and during mitotic exit. Co-activator proteins, inhibitor proteins, protein kinases and phosphatases interact with the APC/C to temporally and spatially control its activity and thus ensure accurate timing of mitotic events.
Collapse
Affiliation(s)
- Sushama Sivakumar
- Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, Oklahoma 73104, USA
| | - Gary J Gorbsky
- Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, Oklahoma 73104, USA
| |
Collapse
|
33
|
Barford D. Understanding the structural basis for controlling chromosome division. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:20130392. [PMID: 25624511 PMCID: PMC4308986 DOI: 10.1098/rsta.2013.0392] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The process of chromosome division, termed mitosis, involves a complex sequence of events that is tightly controlled to ensure that the faithful segregation of duplicated chromosomes is coordinated with each cell division cycle. The large macromolecular complex responsible for regulating this process is the anaphase-promoting complex or cyclosome (APC/C). In humans, the APC/C is assembled from 20 subunits derived from 15 different proteins. The APC/C functions to ubiquitinate cell cycle regulatory proteins, thereby targeting them for destruction by the proteasome. This review describes our research aimed at understanding the structure and mechanism of the APC/C. We have determined the crystal structures of individual subunits and subcomplexes that provide atomic models to interpret density maps of the whole complex derived from single particle cryo-electron microscopy. With this information, we are generating pseudo-atomic models of functional states of the APC/C that provide insights into its overall architecture and mechanisms of substrate recognition, catalysis and regulation by inhibitory complexes.
Collapse
Affiliation(s)
- David Barford
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| |
Collapse
|
34
|
Masuda K, Chiyoda T, Sugiyama N, Segura-Cabrera A, Kabe Y, Ueki A, Banno K, Suematsu M, Aoki D, Ishihama Y, Saya H, Kuninaka S. LATS1 and LATS2 phosphorylate CDC26 to modulate assembly of the tetratricopeptide repeat subcomplex of APC/C. PLoS One 2015; 10:e0118662. [PMID: 25723520 PMCID: PMC4344199 DOI: 10.1371/journal.pone.0118662] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/09/2015] [Indexed: 12/15/2022] Open
Abstract
In budding yeast, the Mitotic Exit Network (MEN) regulates anaphase promoting complex/cyclosome (APC/C) via the Dbf2-Cdc14 signaling cascade. Dbf2 kinase phosphorylates and activates Cdc14 phosphatase, which removes the inhibitory phosphorylation of the APC/C cofactor Cdh1. Although each component of the MEN was highly conserved during evolution, there is presently no evidence supporting direct phosphorylation of CDC14 by large tumor suppressor kinase 1 (LATS1), the human counterpart of Dbf2; hence, it is unclear how LATS1 regulates APC/C. Here, we demonstrate that LATS1 phosphorylates the Thr7 (T7) residue of the APC/C component CDC26 directly. Nocodazole-induced phosphorylation of T7 was reduced by knockdown of LATS1 and LATS2 in HeLa cells, indicating that both of these kinases contribute to the phosphorylation of CDC26 in vivo. The T7 residue of CDC26 is critical for its interaction with APC6, a tetratricopeptide repeat-containing subunit of APC/C, and mutation of this residue to Asp (T7D) reduced the interaction of CDC26 with APC6. Replacement of endogenous CDC26 in HeLa cells with exogenous phosphor-mimic T7D-mutated CDC26 increased the elution size of APC/C subunits in a gel filtration assay, implying a change in the APC/C assembly upon phosphorylation of CDC26. Furthermore, T7D-mutated CDC26 promoted the ubiquitination of polo-like kinase 1, a well-known substrate of APC/C. Overall, these results suggest that LATS1/2 are novel kinases involved in APC/C phosphorylation and indicate a direct regulatory link between LATS1/2 and APC/C.
Collapse
Affiliation(s)
- Kenta Masuda
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Tatsuyuki Chiyoda
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Naoyuki Sugiyama
- Department of Molecular & Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Aldo Segura-Cabrera
- Division of Experimental Hematology & Cancer Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Yasuaki Kabe
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
| | - Arisa Ueki
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Koji Banno
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Makoto Suematsu
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
- CREST, Japan Science and Technology Agency, Tokyo, Japan
| | - Daisuke Aoki
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Yasushi Ishihama
- Department of Molecular & Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hideyuki Saya
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
- * E-mail: (SK); (HS)
| | - Shinji Kuninaka
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
- * E-mail: (SK); (HS)
| |
Collapse
|
35
|
Yamaguchi M, Yu S, Qiao R, Weissmann F, Miller DJ, VanderLinden R, Brown NG, Frye JJ, Peters JM, Schulman BA. Structure of an APC3-APC16 complex: insights into assembly of the anaphase-promoting complex/cyclosome. J Mol Biol 2014; 427:1748-64. [PMID: 25490258 DOI: 10.1016/j.jmb.2014.11.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 11/14/2014] [Accepted: 11/15/2014] [Indexed: 01/05/2023]
Abstract
The anaphase-promoting complex/cyclosome (APC/C) is a massive E3 ligase that controls mitosis by catalyzing ubiquitination of key cell cycle regulatory proteins. The APC/C assembly contains two subcomplexes: the "Platform" centers around a cullin-RING-like E3 ligase catalytic core; the "Arc Lamp" is a hub that mediates transient association with regulators and ubiquitination substrates. The Arc Lamp contains the small subunits APC16, CDC26, and APC13, and tetratricopeptide repeat (TPR) proteins (APC7, APC3, APC6, and APC8) that homodimerize and stack with quasi-2-fold symmetry. Within the APC/C complex, APC3 serves as center for regulation. APC3's TPR motifs recruit substrate-binding coactivators, CDC20 and CDH1, via their C-terminal conserved Ile-Arg (IR) tail sequences. Human APC3 also binds APC16 and APC7 and contains a >200-residue loop that is heavily phosphorylated during mitosis, although the basis for APC3 interactions and whether loop phosphorylation is required for ubiquitination are unclear. Here, we map the basis for human APC3 assembly with APC16 and APC7, report crystal structures of APC3Δloop alone and in complex with the C-terminal domain of APC16, and test roles of APC3's loop and IR tail binding surfaces in APC/C-catalyzed ubiquitination. The structures show how one APC16 binds asymmetrically to the symmetric APC3 dimer and, together with biochemistry and prior data, explain how APC16 recruits APC7 to APC3, show how APC3's C-terminal domain is rearranged in the full APC/C assembly, and visualize residues in the IR tail binding cleft important for coactivator-dependent ubiquitination. Overall, the results provide insights into assembly, regulation, and interactions of TPR proteins and the APC/C.
Collapse
Affiliation(s)
- Masaya Yamaguchi
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Shanshan Yu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Renping Qiao
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Florian Weissmann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Darcie J Miller
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ryan VanderLinden
- Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, TN 38105 USA
| | - Nicholas G Brown
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jeremiah J Frye
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Brenda A Schulman
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, TN 38105 USA.
| |
Collapse
|
36
|
Chang LF, Zhang Z, Yang J, McLaughlin SH, Barford D. Molecular architecture and mechanism of the anaphase-promoting complex. Nature 2014; 513:388-393. [PMID: 25043029 PMCID: PMC4456660 DOI: 10.1038/nature13543] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 05/28/2014] [Indexed: 12/12/2022]
Abstract
The ubiquitination of cell cycle regulatory proteins by the anaphase-promoting complex/cyclosome (APC/C) controls sister chromatid segregation, cytokinesis and the establishment of the G1 phase of the cell cycle. The APC/C is an unusually large multimeric cullin-RING ligase. Its activity is strictly dependent on regulatory coactivator subunits that promote APC/C-substrate interactions and stimulate its catalytic reaction. Because the structures of many APC/C subunits and their organization within the assembly are unknown, the molecular basis for these processes is poorly understood. Here, from a cryo-electron microscopy reconstruction of a human APC/C-coactivator-substrate complex at 7.4 Å resolution, we have determined the complete secondary structural architecture of the complex. With this information we identified protein folds for structurally uncharacterized subunits, and the definitive location of all 20 APC/C subunits within the 1.2 MDa assembly. Comparison with apo APC/C shows that the coactivator promotes a profound allosteric transition involving displacement of the cullin-RING catalytic subunits relative to the degron-recognition module of coactivator and APC10. This transition is accompanied by increased flexibility of the cullin-RING subunits and enhanced affinity for UBCH10-ubiquitin, changes which may contribute to coactivator-mediated stimulation of APC/C E3 ligase activity.
Collapse
Affiliation(s)
- Lei-Fu Chang
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Ziguo Zhang
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Jing Yang
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | | | - David Barford
- Division of Structural Biology, Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| |
Collapse
|
37
|
How chemistry supports cell biology: the chemical toolbox at your service. Trends Cell Biol 2014; 24:751-60. [PMID: 25108565 DOI: 10.1016/j.tcb.2014.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/10/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
Abstract
Chemical biology is a young and rapidly developing scientific field. In this field, chemistry is inspired by biology to create various tools to monitor and modulate biochemical and cell biological processes. Chemical contributions such as small-molecule inhibitors and activity-based probes (ABPs) can provide new and unique insights into previously unexplored cellular processes. This review provides an overview of recent breakthroughs in chemical biology that are likely to have a significant impact on cell biology. We also discuss the application of several chemical tools in cell biology research.
Collapse
|
38
|
Mirabella F, Murison A, Aronson LI, Wardell CP, Thompson AJ, Hanrahan SJ, Fok JHL, Pawlyn C, Kaiser MF, Walker BA, Davies FE, Morgan GJ. A novel functional role for MMSET in RNA processing based on the link between the REIIBP isoform and its interaction with the SMN complex. PLoS One 2014; 9:e99493. [PMID: 24923560 PMCID: PMC4055699 DOI: 10.1371/journal.pone.0099493] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/15/2014] [Indexed: 11/18/2022] Open
Abstract
The chromosomal translocation t(4;14) deregulates MMSET (WHSC1/NSD2) expression and is a poor prognostic factor in multiple myeloma (MM). MMSET encodes two major protein isoforms. We have characterized the role of the shorter isoform (REIIBP) in myeloma cells and identified a clear and novel interaction of REIIBP with members of the SMN (survival of motor neuron) complex that directly affects the assembly of the spliceosomal ribonucleic particles. Using RNA-seq we show that REIIBP influences the RNA splicing pattern of the cell. This new discovery provides novel insights into the understanding of MM pathology, and potential new leads for therapeutic targeting.
Collapse
Affiliation(s)
- Fabio Mirabella
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Alexander Murison
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Lauren I. Aronson
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Christopher P. Wardell
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Andrew J. Thompson
- Proteomics Core Facility, The Institute of Cancer Research, London, United Kingdom
| | - Sarah J. Hanrahan
- Proteomics Core Facility, The Institute of Cancer Research, London, United Kingdom
| | - Jacqueline H. L. Fok
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Charlotte Pawlyn
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Martin F. Kaiser
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Brian A. Walker
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Faith E. Davies
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| | - Gareth J. Morgan
- Centre for Myeloma Research, Division of Molecular Pathology, The Institute of Cancer Research, Sutton, United Kingdom
| |
Collapse
|
39
|
Itzhak D, Bright M, McAndrew P, Mirza A, Newbatt Y, Strover J, Widya M, Thompson A, Morgan G, Collins I, Davies F. Multiple autophosphorylations significantly enhance the endoribonuclease activity of human inositol requiring enzyme 1α. BMC BIOCHEMISTRY 2014; 15:3. [PMID: 24524643 PMCID: PMC3928614 DOI: 10.1186/1471-2091-15-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 01/31/2014] [Indexed: 12/04/2022]
Abstract
Background Endoplasmic reticulum stress, caused by the presence of misfolded proteins, activates the stress sensor inositol-requiring enzyme 1α (IRE1α). The resulting increase in IRE1α RNase activity causes sequence-specific cleavage of X-box binding protein 1 (XBP1) mRNA, resulting in upregulation of the unfolded protein response and cellular adaptation to stress. The precise mechanism of human IRE1α activation is currently unclear. The role of IRE1α kinase activity is disputed, as results from the generation of various kinase-inactivating mutations in either yeast or human cells are discordant. Kinase activity can also be made redundant by small molecules which bind the ATP binding site. We set out to uncover a role for IRE1α kinase activity using wild-type cytosolic protein constructs. Results We show that concentration-dependent oligomerisation is sufficient to cause IRE1α cytosolic domain RNase activity in vitro. We demonstrate a role for the kinase activity by showing that autophosphorylation enhances RNase activity. Inclusion of the IRE1α linker domain in protein constructs allows hyperphosphorylation and further enhancement of RNase activity, highlighting the importance of kinase activity. We show that IRE1α phosphorylation status correlates with an increased propensity to form oligomeric complexes and that forced dimerisation causes great enhancement in RNase activity. In addition we demonstrate that even when IRE1α is forced to dimerise, by a GST-tag, phospho-enhancement of activity is still observed. Conclusions Taken together these experiments support the hypothesis that phosphorylation is important in modulating IRE1α RNase activity which is achieved by increasing the propensity of IRE1α to dimerise. This work supports the development of IRE1α kinase inhibitors for use in the treatment of secretory cancers.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Faith Davies
- From the Division of Cancer Therapeutics, Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK.
| |
Collapse
|
40
|
Panigrahi R, Adina-Zada A, Whelan J, Vrielink A. Ligand recognition by the TPR domain of the import factor Toc64 from Arabidopsis thaliana. PLoS One 2013; 8:e83461. [PMID: 24391770 PMCID: PMC3877065 DOI: 10.1371/journal.pone.0083461] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/04/2013] [Indexed: 01/21/2023] Open
Abstract
The specific targeting of protein to organelles is achieved by targeting signals being recognised by their cognate receptors. Cytosolic chaperones, bound to precursor proteins, are recognized by specific receptors of the import machinery enabling transport into the specific organelle. The aim of this study was to gain greater insight into the mode of recognition of the C-termini of Hsp70 and Hsp90 chaperones by the Tetratricopeptide Repeat (TPR) domain of the chloroplast import receptor Toc64 from Arabidopsis thaliana (At). The monomeric TPR domain binds with 1∶1 stoichiometry in similar micromolar affinity to both Hsp70 and Hsp90 as determined by isothermal titration calorimetry (ITC). Mutations of the terminal EEVD motif caused a profound decrease in affinity. Additionally, this study considered the contributions of residues upstream as alanine scanning experiments of these residues showed reduced binding affinity. Molecular dynamics simulations of the TPR domain helices upon peptide binding predicted that two helices within the TPR domain move backwards, exposing the cradle surface for interaction with the peptide. Our findings from ITC and molecular dynamics studies suggest that AtToc64_TPR does not discriminate between C-termini peptides of Hsp70 and Hsp90.
Collapse
Affiliation(s)
- Rashmi Panigrahi
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia, Australia
| | - Abdussalam Adina-Zada
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia, Australia
| | - James Whelan
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia, Australia
- Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria, Australia
| | - Alice Vrielink
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia, Australia
| |
Collapse
|
41
|
Kim HK, Kim RR, Oh JH, Cho H, Varshavsky A, Hwang CS. The N-terminal methionine of cellular proteins as a degradation signal. Cell 2013; 156:158-69. [PMID: 24361105 DOI: 10.1016/j.cell.2013.11.031] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 09/26/2013] [Accepted: 11/20/2013] [Indexed: 11/28/2022]
Abstract
The Arg/N-end rule pathway targets for degradation proteins that bear specific unacetylated N-terminal residues while the Ac/N-end rule pathway targets proteins through their N(α)-terminally acetylated (Nt-acetylated) residues. Here, we show that Ubr1, the ubiquitin ligase of the Arg/N-end rule pathway, recognizes unacetylated N-terminal methionine if it is followed by a hydrophobic residue. This capability of Ubr1 expands the range of substrates that can be targeted for degradation by the Arg/N-end rule pathway because virtually all nascent cellular proteins bear N-terminal methionine. We identified Msn4, Sry1, Arl3, and Pre5 as examples of normal or misfolded proteins that can be destroyed through the recognition of their unacetylated N-terminal methionine. Inasmuch as proteins bearing the Nt-acetylated N-terminal methionine residue are substrates of the Ac/N-end rule pathway, the resulting complementarity of the Arg/N-end rule and Ac/N-end rule pathways enables the elimination of protein substrates regardless of acetylation state of N-terminal methionine in these substrates.
Collapse
Affiliation(s)
- Heon-Ki Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Ryu-Ryun Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Jang-Hyun Oh
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hanna Cho
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Alexander Varshavsky
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea.
| |
Collapse
|
42
|
Zhang Z, Chang L, Yang J, Conin N, Kulkarni K, Barford D. The four canonical tpr subunits of human APC/C form related homo-dimeric structures and stack in parallel to form a TPR suprahelix. J Mol Biol 2013; 425:4236-48. [PMID: 23583778 PMCID: PMC3898896 DOI: 10.1016/j.jmb.2013.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 03/28/2013] [Accepted: 04/05/2013] [Indexed: 12/18/2022]
Abstract
The anaphase-promoting complex or cyclosome (APC/C) is a large E3 RING-cullin ubiquitin ligase composed of between 14 and 15 individual proteins. A striking feature of the APC/C is that only four proteins are involved in directly recognizing target proteins and catalyzing the assembly of a polyubiquitin chain. All other subunits, which account for >80% of the mass of the APC/C, provide scaffolding functions. A major proportion of these scaffolding subunits are structurally related. In metazoans, there are four canonical tetratricopeptide repeat (TPR) proteins that form homo-dimers (Apc3/Cdc27, Apc6/Cdc16, Apc7 and Apc8/Cdc23). Here, we describe the crystal structure of the N-terminal homo-dimerization domain of Schizosaccharomyces pombe Cdc23 (Cdc23(Nterm)). Cdc23(Nterm) is composed of seven contiguous TPR motifs that self-associate through a related mechanism to those of Cdc16 and Cdc27. Using the Cdc23(Nterm) structure, we generated a model of full-length Cdc23. The resultant "V"-shaped molecule docks into the Cdc23-assigned density of the human APC/C structure determined using negative stain electron microscopy (EM). Based on sequence conservation, we propose that Apc7 forms a homo-dimeric structure equivalent to those of Cdc16, Cdc23 and Cdc27. The model is consistent with the Apc7-assigned density of the human APC/C EM structure. The four canonical homo-dimeric TPR proteins of human APC/C stack in parallel on one side of the complex. Remarkably, the uniform relative packing of neighboring TPR proteins generates a novel left-handed suprahelical TPR assembly. This finding has implications for understanding the assembly of other TPR-containing multimeric complexes.
Collapse
Affiliation(s)
| | | | | | | | - Kiran Kulkarni
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
| | - David Barford
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
| |
Collapse
|
43
|
Kulkarni K, Zhang Z, Chang L, Yang J, da Fonseca PCA, Barford D. Building a pseudo-atomic model of the anaphase-promoting complex. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:2236-43. [PMID: 24189235 PMCID: PMC3817697 DOI: 10.1107/s0907444913018593] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/04/2013] [Indexed: 11/10/2022]
Abstract
The anaphase-promoting complex (APC/C) is a large E3 ubiquitin ligase that regulates progression through specific stages of the cell cycle by coordinating the ubiquitin-dependent degradation of cell-cycle regulatory proteins. Depending on the species, the active form of the APC/C consists of 14-15 different proteins that assemble into a 20-subunit complex with a mass of approximately 1.3 MDa. A hybrid approach of single-particle electron microscopy and protein crystallography of individual APC/C subunits has been applied to generate pseudo-atomic models of various functional states of the complex. Three approaches for assigning regions of the EM-derived APC/C density map to specific APC/C subunits are described. This information was used to dock atomic models of APC/C subunits, determined either by protein crystallography or homology modelling, to specific regions of the APC/C EM map, allowing the generation of a pseudo-atomic model corresponding to 80% of the entire complex.
Collapse
Affiliation(s)
- Kiran Kulkarni
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, England
| | - Ziguo Zhang
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, England
| | - Leifu Chang
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, England
| | - Jing Yang
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, England
| | - Paula C. A. da Fonseca
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, England
| | - David Barford
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, England
| |
Collapse
|
44
|
Abstract
The anaphase-promoting complex or cyclosome (APC/C) is a conserved, multisubunit E3 ubiquitin (Ub) ligase that is active both in dividing and in postmitotic cells. Its contributions to life are especially well studied in the domain of cell division, in which the APC/C lies at the epicenter of a regulatory network that controls the directionality and timing of cell cycle events. Biochemical and structural work is shedding light on the overall organization of APC/C subunits and on the mechanism of substrate recognition and Ub chain initiation and extension as well as on the molecular mechanisms of a checkpoint that seizes control of APC/C activity during mitosis. Here, we review how these recent advancements are modifying our understanding of the APC/C.
Collapse
Affiliation(s)
- Ivana Primorac
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | | |
Collapse
|
45
|
Barford D, Takagi Y, Schultz P, Berger I. Baculovirus expression: tackling the complexity challenge. Curr Opin Struct Biol 2013; 23:357-64. [PMID: 23628287 PMCID: PMC7125881 DOI: 10.1016/j.sbi.2013.03.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/18/2013] [Accepted: 03/29/2013] [Indexed: 10/26/2022]
Abstract
Most essential functions in eukaryotic cells are catalyzed by complex molecular machines built of many subunits. To fully understand their biological function in health and disease, it is imperative to study these machines in their entirety. The provision of many essential multiprotein complexes of higher eukaryotes including humans, can be a considerable challenge, as low abundance and heterogeneity often rule out their extraction from native source material. The baculovirus expression vector system (BEVS), specifically tailored for multiprotein complex production, has proven itself to be uniquely suited for overcoming this impeding bottleneck. Here we highlight recent major achievements in multiprotein complex structure research that were catalyzed by this versatile recombinant complex expression tool.
Collapse
Affiliation(s)
- David Barford
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
| | | | | | | |
Collapse
|
46
|
Shemorry A, Hwang CS, Varshavsky A. Control of protein quality and stoichiometries by N-terminal acetylation and the N-end rule pathway. Mol Cell 2013; 50:540-51. [PMID: 23603116 DOI: 10.1016/j.molcel.2013.03.018] [Citation(s) in RCA: 221] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/04/2013] [Accepted: 03/12/2013] [Indexed: 11/19/2022]
Abstract
N(α)-terminal acetylation of cellular proteins was recently discovered to create specific degradation signals termed Ac/N-degrons and targeted by the Ac/N-end rule pathway. We show that Hcn1, a subunit of the APC/C ubiquitin ligase, contains an Ac/N-degron that is repressed by Cut9, another APC/C subunit and the ligand of Hcn1. Cog1, a subunit of the Golgi-associated COG complex, is also shown to contain an Ac/N-degron. Cog2 and Cog3, direct ligands of Cog1, can repress this degron. The subunit decoy technique was used to show that the long-lived endogenous Cog1 is destabilized and destroyed via its activated (unshielded) Ac/N-degron if the total level of Cog1 increased in a cell. Hcn1 and Cog1 are the first examples of protein regulation through the physiologically relevant transitions that shield and unshield natural Ac/N-degrons. This mechanistically straightforward circuit can employ the demonstrated conditionality of Ac/N-degrons to regulate subunit stoichiometries and other aspects of protein quality control.
Collapse
Affiliation(s)
- Anna Shemorry
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | | | | |
Collapse
|
47
|
Structural and functional insights into the role of the N-terminal Mps1 TPR domain in the SAC (spindle assembly checkpoint). Biochem J 2013; 448:321-8. [PMID: 23067341 DOI: 10.1042/bj20121448] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The SAC (spindle assembly checkpoint) is a surveillance system that ensures the timely and accurate transmission of the genetic material to offspring. The process implies kinetochore targeting of the mitotic kinases Bub1 (budding uninhibited by benzamidine 1), BubR1 (Bub1 related) and Mps1 (monopolar spindle 1), which is mediated by the N-terminus of each kinase. In the present study we report the 1.8 Å (1 Å=0.1 nm) crystal structure of the TPR (tetratricopeptide repeat) domain in the N-terminal region of human Mps1. The structure reveals an overall high similarity to the TPR motif of the mitotic checkpoint kinases Bub1 and BubR1, and a number of unique features that include the absence of the binding site for the kinetochore structural component KNL1 (kinetochore-null 1; blinkin), and determinants of dimerization. Moreover, we show that a stretch of amino acids at the very N-terminus of Mps1 is required for dimer formation, and that interfering with dimerization results in mislocalization and misregulation of kinase activity. The results of the present study provide an important insight into the molecular details of the mitotic functions of Mps1 including features that dictate substrate selectivity and kinetochore docking.
Collapse
|
48
|
Monda JK, Scott DC, Miller DJ, Lydeard J, King D, Harper JW, Bennett EJ, Schulman BA. Structural conservation of distinctive N-terminal acetylation-dependent interactions across a family of mammalian NEDD8 ligation enzymes. Structure 2013; 21:42-53. [PMID: 23201271 PMCID: PMC3786212 DOI: 10.1016/j.str.2012.10.013] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/20/2012] [Accepted: 10/25/2012] [Indexed: 01/07/2023]
Abstract
Little is known about molecular recognition of acetylated N termini, despite prevalence of this modification among eukaryotic cytosolic proteins. We report that the family of human DCN-like (DCNL) co-E3s, which promote ligation of the ubiquitin-like protein NEDD8 to cullin targets, recognizes acetylated N termini of the E2 enzymes UBC12 and UBE2F. Systematic biochemical and biophysical analyses reveal 40- and 10-fold variations in affinities among different DCNL-cullin and DCNL-E2 complexes, contributing to varying efficiencies of different NEDD8 ligation cascades. Structures of DCNL2 and DCNL3 complexes with N-terminally acetylated peptides from UBC12 and UBE2F illuminate a common mechanism by which DCNL proteins recognize N-terminally acetylated E2s and how selectivity for interactions dependent on N-acetyl-methionine are established through side chains recognizing distal residues. Distinct preferences of UBC12 and UBE2F peptides for inhibiting different DCNLs, including the oncogenic DCNL1 protein, suggest it may be possible to develop small molecules blocking specific N-acetyl-methionine-dependent protein interactions.
Collapse
Affiliation(s)
- Julie K. Monda
- Department of Structural Biology and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis TN, 38105
| | - Daniel C. Scott
- Department of Structural Biology and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis TN, 38105,Department of Howard Hughes Medical Institute, St. Jude Children’s Research Hospital, Memphis TN, 38105
| | - Darcie J. Miller
- Department of Structural Biology and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis TN, 38105
| | - John Lydeard
- Department of Cell Biology, Harvard Medical School, Boston MA 02115
| | - David King
- HHMI Mass Spectrometry Laboratory, University of California, Berkeley CA 94720
| | - J. Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston MA 02115
| | - Eric J. Bennett
- Department of Cell Biology, Harvard Medical School, Boston MA 02115,Division of Biological Sciences, University of California San Diego, La Jolla CA 92093
| | - Brenda A. Schulman
- Department of Structural Biology and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis TN, 38105,Department of Howard Hughes Medical Institute, St. Jude Children’s Research Hospital, Memphis TN, 38105
| |
Collapse
|
49
|
Rockenbauch U, Ritz AM, Sacristan C, Roncero C, Spang A. The complex interactions of Chs5p, the ChAPs, and the cargo Chs3p. Mol Biol Cell 2012; 23:4402-15. [PMID: 23015758 PMCID: PMC3496614 DOI: 10.1091/mbc.e11-12-1015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The exomer complex, consisting of ChAPs and Chs5p, exports specialized cargoes from the TGN. ChAPs bind to Chs5p through TPR repeats, whereas cargo specificity of the ChAPs is outside these interaction modules. Chs3p and Chs6p may require a complex interaction to form a complex. The exomer complex is a putative vesicle coat required for the direct transport of a subset of cargoes from the trans-Golgi network (TGN) to the plasma membrane. Exomer comprises Chs5p and the ChAPs family of proteins (Chs6p, Bud7p, Bch1p, and Bch2p), which are believed to act as cargo receptors. In particular, Chs6p is required for the transport of the chitin synthase Chs3p to the bud neck. However, how the ChAPs associate with Chs5p and recognize cargo is not well understood. Using domain-switch chimeras of Chs6p and Bch2p, we show that four tetratricopeptide repeats (TPRs) are involved in interaction with Chs5p. Because these roles are conserved among the ChAPs, the TPRs are interchangeable among different ChAP proteins. In contrast, the N-terminal and the central parts of the ChAPs contribute to cargo specificity. Although the entire N-terminal domain of Chs6p is required for Chs3p export at all cell cycle stages, the central part seems to predominantly favor Chs3p export in small-budded cells. The cargo Chs3p probably also uses a complex motif for the interaction with Chs6, as the C-terminus of Chs3p interacts with Chs6p and is necessary, but not sufficient, for TGN export.
Collapse
|
50
|
Muñoz-Martínez F, García-Fontana C, Rico-Jiménez M, Alfonso C, Krell T. Genes encoding Cher-TPR fusion proteins are predominantly found in gene clusters encoding chemosensory pathways with alternative cellular functions. PLoS One 2012; 7:e45810. [PMID: 23029255 PMCID: PMC3447774 DOI: 10.1371/journal.pone.0045810] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 08/24/2012] [Indexed: 12/14/2022] Open
Abstract
Chemosensory pathways correspond to major signal transduction mechanisms and can be classified into the functional families flagellum-mediated taxis, type four pili-mediated taxis or pathways with alternative cellular functions (ACF). CheR methyltransferases are core enzymes in all of these families. CheR proteins fused to tetratricopeptide repeat (TPR) domains have been reported and we present an analysis of this uncharacterized family. We show that CheR-TPRs are widely distributed in GRAM-negative but almost absent from GRAM-positive bacteria. Most strains contain a single CheR-TPR and its abundance does not correlate with the number of chemoreceptors. The TPR domain fused to CheR is comparatively short and frequently composed of 2 repeats. The majority of CheR-TPR genes were found in gene clusters that harbor multidomain response regulators in which the REC domain is fused to different output domains like HK, GGDEF, EAL, HPT, AAA, PAS, GAF, additional REC, HTH, phosphatase or combinations thereof. The response regulator architectures coincide with those reported for the ACF family of pathways. Since the presence of multidomain response regulators is a distinctive feature of this pathway family, we conclude that CheR-TPR proteins form part of ACF type pathways. The diversity of response regulator output domains suggests that the ACF pathways form a superfamily which regroups many different regulatory mechanisms, in which all CheR-TPR proteins appear to participate. In the second part we characterize WspC of Pseudomonas putida, a representative example of CheR-TPR. The affinities of WspC-Pp for S-adenosylmethionine and S-adenosylhomocysteine were comparable to those of prototypal CheR, indicating that WspC-Pp activity is in analogy to prototypal CheRs controlled by product feed-back inhibition. The removal of the TPR domain did not impact significantly on the binding constants and consequently not on the product feed-back inhibition. WspC-Pp was found to be monomeric, which rules out a role of the TPR domain in self-association.
Collapse
Affiliation(s)
- Francisco Muñoz-Martínez
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Cristina García-Fontana
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Miriam Rico-Jiménez
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | | | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
- * E-mail:
| |
Collapse
|