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Padi SKR, Vos MR, Godek RJ, Fuller JR, Kruse T, Hein JB, Nilsson J, Kelker MS, Page R, Peti W. Cryo-EM structures of PP2A:B55-FAM122A and PP2A:B55-ARPP19. Nature 2024; 625:195-203. [PMID: 38123684 PMCID: PMC10765524 DOI: 10.1038/s41586-023-06870-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/15/2023] [Indexed: 12/23/2023]
Abstract
Progression through the cell cycle is controlled by regulated and abrupt changes in phosphorylation1. Mitotic entry is initiated by increased phosphorylation of mitotic proteins, a process driven by kinases2, whereas mitotic exit is achieved by counteracting dephosphorylation, a process driven by phosphatases, especially PP2A:B553. Although the role of kinases in mitotic entry is well established, recent data have shown that mitosis is only successfully initiated when the counterbalancing phosphatases are also inhibited4. Inhibition of PP2A:B55 is achieved by the intrinsically disordered proteins ARPP195,6 and FAM122A7. Despite their critical roles in mitosis, the mechanisms by which they achieve PP2A:B55 inhibition is unknown. Here, we report the single-particle cryo-electron microscopy structures of PP2A:B55 bound to phosphorylated ARPP19 and FAM122A. Consistent with our complementary NMR spectroscopy studies, both intrinsically disordered proteins bind PP2A:B55, but do so in highly distinct manners, leveraging multiple distinct binding sites on B55. Our extensive structural, biophysical and biochemical data explain how substrates and inhibitors are recruited to PP2A:B55 and provide a molecular roadmap for the development of therapeutic interventions for PP2A:B55-related diseases.
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Affiliation(s)
- Sathish K R Padi
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Margaret R Vos
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Rachel J Godek
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | | | - Thomas Kruse
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Jamin B Hein
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Jakob Nilsson
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | | | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA.
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA.
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2
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Padi SK, Vos MR, Godek RJ, Fuller JR, Kruse T, Hein JB, Nilsson J, Kelker MS, Page R, Peti W. Cryo-EM structures of PP2A:B55-FAM122A and PP2A:B55-ARPP19. bioRxiv 2023:2023.08.31.555365. [PMID: 37693408 PMCID: PMC10491220 DOI: 10.1101/2023.08.31.555365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Progression through the cell cycle is controlled by regulated and abrupt changes in phosphorylation.1 Mitotic entry is initiated by increased phosphorylation of mitotic proteins, a process driven by kinases,2 while mitotic exit is achieved by counteracting dephosphorylation, a process driven by phosphatases, especially PP2A:B55.3 While the role of kinases in mitotic entry is well-established, recent data have shown that mitosis is only successfully initiated when the counterbalancing phosphatases are also inhibited.4 For PP2A:B55, inhibition is achieved by the two intrinsically disordered proteins (IDPs), ARPP19 (phosphorylation-dependent)6,7 and FAM122A5 (inhibition is phosphorylation-independent). Despite their critical roles in mitosis, the mechanisms by which they achieve PP2A:B55 inhibition is unknown. Here, we report the cryo-electron microscopy structures of PP2A:B55 bound to phosphorylated ARPP19 and FAM122A. Consistent with our complementary NMR spectroscopy studies both IDPs bind PP2A:B55, but do so in highly distinct manners, unexpectedly leveraging multiple distinct binding sites on B55. Our extensive structural, biophysical and biochemical data explain how substrates and inhibitors are recruited to PP2A:B55 and provides a molecular roadmap for the development of therapeutic interventions for PP2A:B55 related diseases.
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Affiliation(s)
- Sathish K.R. Padi
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, USA
| | - Margaret R. Vos
- Department of Cell Biology, University of Connecticut Health Center, Farmington, USA
| | - Rachel J. Godek
- Department of Cell Biology, University of Connecticut Health Center, Farmington, USA
| | | | - Thomas Kruse
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Jamin B. Hein
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Jakob Nilsson
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | | | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, USA
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, USA
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3
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Dementiev A, Board J, Sitaram A, Hey T, Kelker MS, Xu X, Hu Y, Vidal-Quist C, Chikwana V, Griffin S, McCaskill D, Wang NX, Hung SC, Chan MK, Lee MM, Hughes J, Wegener A, Aroian RV, Narva KE, Berry C. The pesticidal Cry6Aa toxin from Bacillus thuringiensis is structurally similar to HlyE-family alpha pore-forming toxins. BMC Biol 2016; 14:71. [PMID: 27576487 PMCID: PMC5004264 DOI: 10.1186/s12915-016-0295-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/10/2016] [Indexed: 12/02/2022] Open
Abstract
Background The Cry6 family of proteins from Bacillus thuringiensis represents a group of powerful toxins with great potential for use in the control of coleopteran insects and of nematode parasites of importance to agriculture. These proteins are unrelated to other insecticidal toxins at the level of their primary sequences and the structure and function of these proteins has been poorly studied to date. This has inhibited our understanding of these toxins and their mode of action, along with our ability to manipulate the proteins to alter their activity to our advantage. To increase our understanding of their mode of action and to facilitate further development of these proteins we have determined the structure of Cry6Aa in protoxin and trypsin-activated forms and demonstrated a pore-forming mechanism of action. Results The two forms of the toxin were resolved to 2.7 Å and 2.0 Å respectively and showed very similar structures. Cry6Aa shows structural homology to a known class of pore-forming toxins including hemolysin E from Escherichia coli and two Bacillus cereus proteins: the hemolytic toxin HblB and the NheA component of the non-hemolytic toxin (pfam05791). Cry6Aa also shows atypical features compared to other members of this family, including internal repeat sequences and small loop regions within major alpha helices. Trypsin processing was found to result in the loss of some internal sequences while the C-terminal region remains disulfide-linked to the main core of the toxin. Based on the structural similarity of Cry6Aa to other toxins, the mechanism of action of the toxin was probed and its ability to form pores in vivo in Caenorhabditis elegans was demonstrated. A non-toxic mutant was also produced, consistent with the proposed pore-forming mode of action. Conclusions Cry6 proteins are members of the alpha helical pore-forming toxins – a structural class not previously recognized among the Cry toxins of B. thuringiensis and representing a new paradigm for nematocidal and insecticidal proteins. Elucidation of both the structure and the pore-forming mechanism of action of Cry6Aa now opens the way to more detailed analysis of toxin specificity and the development of new toxin variants with novel activities. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0295-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Jason Board
- Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff, CF15 8FA, UK
| | - Anand Sitaram
- University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA, 01605-2377, USA
| | - Timothy Hey
- Dow AgroSciences, LLC, Indianapolis, IN, USA.,Present address: Indiana State Department of Health Laboratories, Indianapolis, IN, USA
| | - Matthew S Kelker
- Dow AgroSciences, LLC, Indianapolis, IN, USA.,Present address: Xylogenics, LLC, Indianapolis, IN, USA
| | - Xiaoping Xu
- Dow AgroSciences, LLC, Indianapolis, IN, USA
| | - Yan Hu
- University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA, 01605-2377, USA
| | - Cristian Vidal-Quist
- Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff, CF15 8FA, UK.,Present address: Laboratorio de Interacción Planta-Insecto, Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas - CSIC, Madrid, Spain
| | | | | | | | - Nick X Wang
- Dow AgroSciences, LLC, Indianapolis, IN, USA
| | | | - Michael K Chan
- School of Life Sciences and Center of Novel Biomaterials, The Chinese University of Hong Kong, Shatin, HK SAR, China
| | - Marianne M Lee
- School of Life Sciences and Center of Novel Biomaterials, The Chinese University of Hong Kong, Shatin, HK SAR, China
| | - Jessica Hughes
- Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff, CF15 8FA, UK.,Present address: Antimicrobial Reference Laboratory, Southmead Hospital, Westbury-on-Trym, Bristol, BS10 5NB, UK
| | - Alice Wegener
- Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff, CF15 8FA, UK
| | - Raffi V Aroian
- University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA, 01605-2377, USA
| | | | - Colin Berry
- Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff, CF15 8FA, UK.
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4
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Kelker MS, Berry C, Evans SL, Pai R, McCaskill DG, Wang NX, Russell JC, Baker MD, Yang C, Pflugrath JW, Wade M, Wess TJ, Narva KE. Structural and biophysical characterization of Bacillus thuringiensis insecticidal proteins Cry34Ab1 and Cry35Ab1. PLoS One 2014; 9:e112555. [PMID: 25390338 PMCID: PMC4229197 DOI: 10.1371/journal.pone.0112555] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 10/07/2014] [Indexed: 11/18/2022] Open
Abstract
Bacillus thuringiensis strains are well known for the production of insecticidal proteins upon sporulation and these proteins are deposited in parasporal crystalline inclusions. The majority of these insect-specific toxins exhibit three domains in the mature toxin sequence. However, other Cry toxins are structurally and evolutionarily unrelated to this three-domain family and little is known of their three dimensional structures, limiting our understanding of their mechanisms of action and our ability to engineer the proteins to enhance their function. Among the non-three domain Cry toxins, the Cry34Ab1 and Cry35Ab1 proteins from B. thuringiensis strain PS149B1 are required to act together to produce toxicity to the western corn rootworm (WCR) Diabrotica virgifera virgifera Le Conte via a pore forming mechanism of action. Cry34Ab1 is a protein of ∼14 kDa with features of the aegerolysin family (Pfam06355) of proteins that have known membrane disrupting activity, while Cry35Ab1 is a ∼44 kDa member of the toxin_10 family (Pfam05431) that includes other insecticidal proteins such as the binary toxin BinA/BinB. The Cry34Ab1/Cry35Ab1 proteins represent an important seed trait technology having been developed as insect resistance traits in commercialized corn hybrids for control of WCR. The structures of Cry34Ab1 and Cry35Ab1 have been elucidated to 2.15 Å and 1.80 Å resolution, respectively. The solution structures of the toxins were further studied by small angle X-ray scattering and native electrospray ion mobility mass spectrometry. We present here the first published structure from the aegerolysin protein domain family and the structural comparisons of Cry34Ab1 and Cry35Ab1 with other pore forming toxins.
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Affiliation(s)
- Matthew S. Kelker
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Colin Berry
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Steven L. Evans
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Reetal Pai
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | | | - Nick X. Wang
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Joshua C. Russell
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Matthew D. Baker
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Cheng Yang
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - J. W. Pflugrath
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - Matthew Wade
- School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Tim J. Wess
- School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Kenneth E. Narva
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
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Kelker MS, Page R, Peti W. Crystal structures of protein phosphatase-1 bound to nodularin-R and tautomycin: a novel scaffold for structure-based drug design of serine/threonine phosphatase inhibitors. J Mol Biol 2008; 385:11-21. [PMID: 18992256 DOI: 10.1016/j.jmb.2008.10.053] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 10/08/2008] [Accepted: 10/09/2008] [Indexed: 11/15/2022]
Abstract
Protein phosphatase 1 occurs in all tissues and regulates many pathways, ranging from cell-cycle progression to carbohydrate metabolism. Many naturally occurring, molecular toxins modulate PP1 activity, though the exact mechanism of this differential regulation is not understood. A detailed elucidation of these interactions is crucial for understanding the cellular basis of phosphatase function and signaling pathways but, more importantly, they can serve as the basis for highly specific therapeutics, e.g. against cancer. We report the crystal structures of PP1 in complex with nodularin-R at 1.63 A and tautomycin at 1.70 A resolution. The PP1:nodularin-R complex was used to demonstrate the utility of our improved PP1 production technique, which produces highly active, soluble PP1. Tautomycin is one of the few toxins that reportedly preferentially binds PP1>PP2A. Therefore, the PP1:tautomycin structure is the first complex structure with a toxin with preferred PP1 specificity. Furthermore, since tautomycin is a linear non-peptide-based toxin, our reported structure will aid the design of lead compounds for novel PP1-specific pharmaceuticals.
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Affiliation(s)
- Matthew S Kelker
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02903, USA
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6
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Abstract
Neurabin and spinophilin are neuronal scaffolding proteins that play important roles in the regulation of synaptic transmission through their ability to target protein phosphatase 1 (PP1) to dendritic spines where PP1 dephosphorylates and inactivates glutamate receptors. However, thus far, it is still unknown how neurabin and spinophilin themselves are targeted to these membrane receptors. Spinophilin and neurabin contain a single PDZ domain, a common protein-protein interaction recognition motif, which are 86% identical in sequence. We report the structures of both the neurabin and spinophilin PDZ domains determined using biomolecular NMR spectroscopy. These proteins form the canonical PDZ domain fold. However, despite their high degree of sequence identity, there are distinct and significant structural differences between them, especially between the peptide binding pockets. Using two-dimensional 1H-15N HSQC NMR analysis, we demonstrate that C-terminal peptide ligands derived from glutamatergic AMPA and NMDA receptors and cytosolic proteins directly and differentially bind spinophilin and neurabin PDZ domains. This peptide binding data also allowed us to classify the neurabin and spinophilin PDZ domains as the first identified neuronal hybrid class V PDZ domains, which are capable of binding both class I and II peptides. Finally, the ability to bind to glutamate receptor subunits suggests that the PDZ domains of neurabin and spinophilin are important for targeting PP1 to C-terminal phosphorylation sites in AMPA and NMDA receptor subunits.
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Affiliation(s)
- Matthew S Kelker
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, 70 Ship Street, Box G-E3, Providence, Rhode Island 02912, USA
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7
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Affiliation(s)
- Matthew S Kelker
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
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8
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Abstract
Toll-like receptors (TLRs) play key roles in activating immune responses during infection. The human TLR3 ectodomain structure at 2.1 angstroms reveals a large horseshoe-shaped solenoid assembled from 23 leucine-rich repeats (LRRs). Asparagines conserved in the 24-residue LRR motif contribute extensive hydrogen-bonding networks for solenoid stabilization. TLR3 is largely masked by carbohydrate, but one face is glycosylation-free, which suggests its potential role in ligand binding and oligomerization. Highly conserved surface residues and a TLR3-specific LRR insertion form a homodimer interface in the crystal, whereas two patches of positively charged residues and a second insertion would provide an appropriate binding site for double-stranded RNA.
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Affiliation(s)
- Jungwoo Choe
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, Scripps Research Institute (TSRI), 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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9
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Foss TR, Kelker MS, Wiseman RL, Wilson IA, Kelly JW. Kinetic Stabilization of the Native State by Protein Engineering: Implications for Inhibition of Transthyretin Amyloidogenesis. J Mol Biol 2005; 347:841-54. [PMID: 15769474 DOI: 10.1016/j.jmb.2005.01.050] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Revised: 01/19/2005] [Accepted: 01/21/2005] [Indexed: 11/23/2022]
Abstract
The amyloidogenic homotetrameric protein transthyretin (TTR) must undergo rate-limiting dissociation to partially denatured monomers in order to aggregate. TTR contains two distinct quaternary interfaces, one of which defines the binding sites for thyroxine and small-molecule amyloidogenesis inhibitors. Kinetic stabilization of the tetramer can be accomplished either by the binding of amyloidogenesis inhibitors selectively to the native state over the dissociative transition state or by the introduction of trans-suppressor subunits (T119M) into heterotetramers to destabilize the dissociative transition state. In each case, increasing the dissociation activation barrier prevents tetramer dissociation. Herein, we demonstrate that tethering two subunits whose quaternary interface defines the thyroxine binding site also dramatically increases the barrier for tetramer dissociation, apparently by destabilization of the dissociative transition state. The tethered construct (TTR-L-TTR)2 is structurally and functionally equivalent to wild-type TTR. Urea is unable to denature (TTR-L-TTR)2, yet it is able to maintain the denatured state once denaturation is achieved by GdnHCl treatment, suggesting that (TTR-L-TTR)2 is kinetically rather than thermodynamically stabilized, consistent with the identical wild-type TTR and (TTR-L-TTR)2 GdnHCl denaturation curves. Studies focused on a construct containing a single TTR-L-TTR chain and two normal monomer subunits establish that alteration of only one quaternary structural interface is sufficient to impose kinetic stabilization on the entire quaternary structure.
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Affiliation(s)
- Ted R Foss
- Department of Chemistry and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
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10
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Wiseman RL, Johnson SM, Kelker MS, Foss T, Wilson IA, Kelly JW. Kinetic Stabilization of an Oligomeric Protein by a Single Ligand Binding Event. J Am Chem Soc 2005; 127:5540-51. [PMID: 15826192 DOI: 10.1021/ja042929f] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein native state stabilization imposed by small molecule binding is an attractive strategy to prevent the misfolding and misassembly processes associated with amyloid diseases. Transthyretin (TTR) amyloidogenesis requires rate-limiting tetramer dissociation before misassembly of a partially denatured monomer ensues. Selective stabilization of the native TTR tetramer over the dissociative transition state by small molecule binding to both thyroxine binding sites raises the kinetic barrier of tetramer dissociation, preventing amyloidogenesis. Assessing the amyloidogenicity of a TTR tetramer having only one amyloidogenesis inhibitor (I) bound is challenging because the two small molecule binding constants are generally not distinct enough to allow for the exclusive formation of TTR.I in solution to the exclusion of TTR.I(2) and unliganded TTR. Herein, we report a method to tether one fibril formation inhibitor to TTR by disulfide bond formation. Occupancy of only one of the two thyroxine binding sites is sufficient to inhibit tetramer dissociation in 6.0 M urea and amyloidogenesis under acidic conditions by imposing kinetic stabilization on the entire tetramer. The sufficiency of single occupancy for stabilizing the native state of TTR provides the incentive to search for compounds displaying striking negative binding cooperativity (e.g., K(d1) in nanomolar range and K(d2) in the micromolar to millimolar range), enabling lower doses of inhibitor to be employed in the clinic, mitigating potential side effects.
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Affiliation(s)
- R Luke Wiseman
- Department of Chemistry, the Department of Molecular Biology, and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, BCC 265, La Jolla, California 92037, USA
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Kelker MS, Debler EW, Wilson IA. Crystal Structure of Mouse Triggering Receptor Expressed on Myeloid Cells 1 (TREM-1) at 1.76Å. J Mol Biol 2004; 344:1175-81. [PMID: 15561137 DOI: 10.1016/j.jmb.2004.10.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2004] [Revised: 10/05/2004] [Accepted: 10/05/2004] [Indexed: 10/26/2022]
Abstract
Triggering receptor expressed on myeloid cells (TREM) 1 is an activating receptor expressed on myeloid cells whose ligand(s) remain elusive. TREM-1 stimulation activates neutrophils and monocytes and induces the secretion of pro-inflammatory molecules, which amplifies the Toll-like receptor-initiated responses to invading pathogens. In addition, TREM-1 mediates the septic shock pathway, and thus represents a potential therapeutic target. We report the crystal structure of the mouse TREM-1 extracellular domain at 1.76A resolution. The mouse extracellular domain is monomeric, consistent with our previous human TREM-1 structure, and strongly supports the contention that the globular TREM-1 head is a monomer contrary to proposals of a symmetric dimer.
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Affiliation(s)
- Matthew S Kelker
- Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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12
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Kelker MS, Foss TR, Peti W, Teyton L, Kelly JW, Wüthrich K, Wilson IA. Crystal Structure of Human Triggering Receptor Expressed on Myeloid Cells 1 (TREM-1) at 1.47Å. J Mol Biol 2004; 342:1237-48. [PMID: 15351648 DOI: 10.1016/j.jmb.2004.07.089] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Revised: 07/13/2004] [Accepted: 07/26/2004] [Indexed: 11/18/2022]
Abstract
The triggering receptor expressed on myeloid cells (TREM) family of single extracellular immunoglobulin receptors includes both activating and inhibitory isoforms whose ligands are unknown. TREM-1 activation amplifies the Toll-like receptor initiated responses to invading pathogens allowing the secretion of pro-inflammatory chemokines and cytokines. Hence, TREM-1 amplifies the inflammation induced by both bacteria and fungi, and thus represents a potential therapeutic target. We report the crystal structure of the human TREM-1 extracellular domain at 1.47 A resolution. The overall fold places it within the V-type immunoglobulin domain family and reveals close homology with Ig domains from antibodies, T-cell receptors and other activating receptors, such as NKp44. With the additional use of analytical ultracentrifugation and 1H NMR spectroscopy of both human and mouse TREM-1, we have conclusively demonstrated the monomeric state of this extracellular ectodomain in solution and, presumably, of the TREM family in general.
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Affiliation(s)
- Matthew S Kelker
- Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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13
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Rudolph MG, Kelker MS, Schneider TR, Yeates TO, Oseroff V, Heidary DK, Jennings PA, Wilson IA. Use of multiple anomalous dispersion to phase highly merohedrally twinned crystals of interleukin-1beta. Acta Crystallogr D Biol Crystallogr 2003; 59:290-8. [PMID: 12554939 DOI: 10.1107/s0907444902021704] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2002] [Accepted: 11/22/2002] [Indexed: 11/11/2022]
Abstract
The crystal structure at 1.54 A resolution of a double mutant of interleukin-1beta (F42W/W120F), a cytokine secreted by macrophages, was determined by multiple-wavelength anomalous dispersion (MAD) using data from highly twinned selenomethionine-modified crystals. The space group is P4(3), with unit-cell parameters a = b = 53.9, c = 77.4 A. Self-rotation function analysis and various intensity statistics revealed the presence of merohedral twinning in crystals of both the native (twinning fraction alpha approximately 0.35) and SeMet (alpha approximately 0.40) forms. Structure determination and refinement are discussed with emphasis on the possible reasons for successful phasing using untreated twinned MAD data.
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Affiliation(s)
- Markus G Rudolph
- Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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