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Ramatsui L, Dongola TH, Zininga T, Multhoff G, Shonhai A. Human granzyme B binds Plasmodium falciparum Hsp70-x and mediates antiplasmodial activity in vitro. Cell Stress Chaperones 2023; 28:321-331. [PMID: 37074531 PMCID: PMC10167072 DOI: 10.1007/s12192-023-01339-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 03/15/2023] [Accepted: 03/21/2023] [Indexed: 04/20/2023] Open
Abstract
Cell surface-bound human Hsp70 (hHsp70) sensitises tumour cells to the cytolytic attack of natural killer (NK) cells through the mediation of apoptosis-inducing serine protease, granzyme B (GrB). hHsp70 is thought to recruit NK cells to the immunological synapse via the extracellularly exposed 14 amino acid sequence, TKDNNLLGRFELSG, known as the TKD motif of Hsp70. Plasmodium falciparum-infected red blood cells (RBCs) habour both hHsp70 and an exported parasite Hsp70 termed PfHsp70-x. Both PfHsp70-x and hHsp70 share conserved TKD motifs. The role of PfHsp70-x in facilitating GrB uptake in malaria parasite-infected RBCs remains unknown, but hHsp70 enables a perforin-independent uptake of GrB into tumour cells. In the current study, we comparatively investigated the direct binding of GrB to either PfHsp70-x or hHsp70 in vitro. Using ELISA, slot blot assay and surface plasmon resonance (SPR) analysis, we demonstrated a direct interaction of GrB with hHsp70 and PfHsp70-x. SPR analysis revealed a higher affinity of GrB for PfHsp70-x than hHsp70. In addition, we established that the TKD motif of PfHsp70-x directly interacts with GrB. The data further suggest that the C-terminal EEVN motif of PfHsp70-x augments the affinity of PfHsp70-x for GrB but is not a prerequisite for the binding. A potent antiplasmodial activity (IC50 of 0.5 µM) of GrB could be demonstrated. These findings suggest that the uptake of GrB by parasite-infected RBCs might be mediated by both hHsp70 and PfHsp70-x. The combined activity of both proteins could account for the antiplasmodial activity of GrB at the blood stage.
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Affiliation(s)
- Lebogang Ramatsui
- Department of Biochemistry and Microbiology, Faculty of Science, University of Venda, Engineering & Agriculture, Thohoyandou, 0950, Limpopo, South Africa
| | - Tendamudzimu Harmfree Dongola
- Department of Biochemistry and Microbiology, Faculty of Science, University of Venda, Engineering & Agriculture, Thohoyandou, 0950, Limpopo, South Africa
| | - Tawanda Zininga
- Department of Biochemistry and Microbiology, Faculty of Science, University of Venda, Engineering & Agriculture, Thohoyandou, 0950, Limpopo, South Africa
- Department of Biochemistry, Stellenbosch University, Stellenbosch, 7600, South Africa
| | - Gabriele Multhoff
- Klinik Und Poliklinik Für Strahlentherapie Und Radiologische Onkologie, Klinikum Rechts Der Isar and Central Institute for Translational Cancer Research TU München, TranslaTUM) Einsteinstr. 25, 81675, Munich, Germany
| | - Addmore Shonhai
- Department of Biochemistry and Microbiology, Faculty of Science, University of Venda, Engineering & Agriculture, Thohoyandou, 0950, Limpopo, South Africa.
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Mansilla S, Tórtora V, Pignataro F, Sastre S, Castro I, Chiribao ML, Robello C, Zeida A, Santos J, Castro L. Redox sensitive human mitochondrial aconitase and its interaction with frataxin: In vitro and in silico studies confirm that it takes two to tango. Free Radic Biol Med 2023; 197:71-84. [PMID: 36738801 DOI: 10.1016/j.freeradbiomed.2023.01.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/11/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023]
Abstract
Mitochondrial aconitase (ACO2) has been postulated as a redox sensor in the tricarboxylic acid cycle. Its high sensitivity towards reactive oxygen and nitrogen species is due to its particularly labile [4Fe-4S]2+ prosthetic group which yields an inactive [3Fe-4S]+ cluster upon oxidation. Moreover, ACO2 was found as a main oxidant target during aging and in pathologies where mitochondrial dysfunction is implied. Herein, we report the expression and characterization of recombinant human ACO2 and its interaction with frataxin (FXN), a protein that participates in the de novo biosynthesis of Fe-S clusters. A high yield of pure ACO2 (≥99%, 22 ± 2 U/mg) was obtained and kinetic parameters for citrate, isocitrate, and cis-aconitate were determined. Superoxide, carbonate radical, peroxynitrite, and hydrogen peroxide reacted with ACO2 with second-order rate constants of 108, 108, 105, and 102 M-1 s-1, respectively. Temperature-induced unfolding assessed by tryptophan fluorescence of ACO2 resulted in apparent melting temperatures of 51.1 ± 0.5 and 43.6 ± 0.2 °C for [4Fe-4S]2+ and [3Fe-4S]+ states of ACO2, sustaining lower thermal stability upon cluster oxidation. Differences in protein dynamics produced by the Fe-S cluster redox state were addressed by molecular dynamics simulations. Reactivation of [3Fe-4S]+-ACO2 by FXN was verified by activation assays and direct iron-dependent interaction was confirmed by protein-protein interaction ELISA and fluorescence spectroscopic assays. Multimer modeling and protein-protein docking predicted an ACO2-FXN complex where the metal ion binding region of FXN approaches the [3Fe-4S]+ cluster, supporting that FXN is a partner for reactivation of ACO2 upon oxidative cluster inactivation.
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Affiliation(s)
- Santiago Mansilla
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Métodos Cuantitativos, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Verónica Tórtora
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Educación Médica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Florencia Pignataro
- Instituto de Biociencias, Biotecnología y Biología traslacional, Facultad de Ciencias Exactas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Santiago Sastre
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Biofísica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Ignacio Castro
- Instituto de Biociencias, Biotecnología y Biología traslacional, Facultad de Ciencias Exactas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ma Laura Chiribao
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Laboratorio de Interacciones Hospedero-Patógeno, Institut Pasteur de Montevideo, Uruguay
| | - Carlos Robello
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Laboratorio de Interacciones Hospedero-Patógeno, Institut Pasteur de Montevideo, Uruguay
| | - Ari Zeida
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Javier Santos
- Instituto de Biociencias, Biotecnología y Biología traslacional, Facultad de Ciencias Exactas, Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - Laura Castro
- Centro de Investigaciones Biomédicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
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Baroni L, Abreu-Filho PG, Pereira LM, Nagl M, Yatsuda AP. Recombinant actin-depolymerizing factor of the apicomplexan Neospora caninum (NcADF) is susceptible to oxidation. Front Cell Infect Microbiol 2022; 12:952720. [PMID: 36601306 PMCID: PMC9806845 DOI: 10.3389/fcimb.2022.952720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/21/2022] [Indexed: 12/24/2022] Open
Abstract
Neospora caninum is a member of Apicomplexa Phylum and the causative agent of neosporosis, a disease responsible for abortions in cattle. Apicomplexan parasites have a limited set of actin-binding proteins conducting the regulation of the dynamics of nonconventional actin. The parasite actin-based motility is implicated in the parasite invasion process in the host cell. Once no commercial strategy for the neosporosis control is available, the interference in the parasite actin function may result in novel drug targets. Actin-depolymerization factor (ADF) is a member of the ADF/cofilin family, primarily known for its function in actin severing and depolymerization. ADF/cofilins are versatile proteins modulated by different mechanisms, including reduction and oxidation. In apicomplexan parasites, the mechanisms involved in the modulation of ADF function are barely explored and the effects of oxidation in the protein are unknown so far. In this study, we used the oxidants N-chlorotaurine (NCT) and H2O2 to investigate the susceptibility of the recombinant N. caninum ADF (NcADF) to oxidation. After exposing the protein to either NCT or H2O2, the dimerization status and cysteine residue oxidation were determined. Also, the interference of NcADF oxidation in the interaction with actin was assessed. The treatment of the recombinant protein with oxidants reversibly induced the production of dimers, indicating that disulfide bonds between NcADF cysteine residues were formed. In addition, the exposure of NcADF to NCT resulted in more efficient oxidation of the cysteine residues compared to H2O2. Finally, the oxidation of NcADF by NCT reduced the ability of actin-binding and altered the function of NcADF in actin polymerization. Altogether, our results clearly show that recombinant NcADF is sensitive to redox conditions, indicating that the function of this protein in cellular processes involving actin dynamics may be modulated by oxidation.
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Affiliation(s)
- Luciana Baroni
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Péricles Gama Abreu-Filho
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Luiz Miguel Pereira
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Markus Nagl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Ana Patricia Yatsuda
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil,*Correspondence: Ana Patricia Yatsuda,
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Early Divergence of the C-Terminal Variable Region of Troponin T Via a Pair of Mutually Exclusive Alternatively Spliced Exons Followed by a Selective Fixation in Vertebrate Heart. J Mol Evol 2022; 90:452-467. [PMID: 36171395 PMCID: PMC10080876 DOI: 10.1007/s00239-022-10075-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 09/13/2022] [Indexed: 10/14/2022]
Abstract
Troponin T (TnT) is the thin filament anchoring subunit of troponin complex and plays an organizer role in the Ca2+-regulation of striated muscle contraction. From an ancestral gene emerged ~ 700 million years ago in Bilateria, three homologous genes have evolved in vertebrates to encode muscle type-specific isoforms of TnT. Alternative splicing variants of TnT are present in vertebrate and invertebrate muscles to add functional diversity. While the C-terminal region of TnT is largely conserved, it contains an alternatively spliced segment emerged early in C. elegans, which has evolved into a pair of mutually exclusive exons in arthropods (10A and 10B of Drosophila TpnT gene) and vertebrates (16 and 17 of fast skeletal muscle Tnnt3 gene). The C-terminal alternatively spliced segment of TnT interfaces with the other two subunits of troponin with functional significance. The vertebrate cardiac TnT gene that emerged from duplication of the fast TnT gene has eliminated this alternative splicing by the fixation of an exon 17-like constitutive exon, indicating a functional value in slower and rhythmic contractions. The vertebrate slow skeletal muscle TnT gene that emerged from duplication of the cardiac TnT gene has the exon 17-like structure conserved, indicating its further function in sustained and fatigue resistant contractions. This functionality-based evolution is consistent with the finding that exon 10B-encoded segment of Drosophila TnT homologous to the exon 17-encoded segment of vertebrate fast TnT is selectively expressed in insect heart and leg muscles. The evolution of the C-terminal variable region of TnT demonstrates a submolecular mechanism in modifying striated muscle contractility and for the treatment of muscle and heart diseases.
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Wu X, Zhang Q, Guo Y, Zhang H, Guo X, You Q, Wang L. Methods for the Discovery and Identification of Small Molecules Targeting Oxidative Stress-Related Protein–Protein Interactions: An Update. Antioxidants (Basel) 2022; 11:antiox11040619. [PMID: 35453304 PMCID: PMC9025695 DOI: 10.3390/antiox11040619] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 02/04/2023] Open
Abstract
The oxidative stress response pathway is one of the hotspots of current pharmaceutical research. Many proteins involved in these pathways work through protein–protein interactions (PPIs). Hence, targeting PPI to develop drugs for an oxidative stress response is a promising strategy. In recent years, small molecules targeting protein–protein interactions (PPIs), which provide efficient methods for drug discovery, are being investigated by an increasing number of studies. However, unlike the enzyme–ligand binding mode, PPIs usually exhibit large and dynamic binding interfaces, which raise additional challenges for the discovery and optimization of small molecules and for the biochemical techniques used to screen compounds and study structure–activity relationships (SARs). Currently, multiple types of PPIs have been clustered into different classes, which make it difficult to design stationary methods for small molecules. Deficient experimental methods are plaguing medicinal chemists and are becoming a major challenge in the discovery of PPI inhibitors. In this review, we present current methods that are specifically used in the discovery and identification of small molecules that target oxidative stress-related PPIs, including proximity-based, affinity-based, competition-based, structure-guided, and function-based methods. Our aim is to introduce feasible methods and their characteristics that are implemented in the discovery of small molecules for different types of PPIs. For each of these methods, we highlight successful examples of PPI inhibitors associated with oxidative stress to illustrate the strategies and provide insights for further design.
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Affiliation(s)
- Xuexuan Wu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; (X.W.); (Q.Z.); (Y.G.); (H.Z.)
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Qiuyue Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; (X.W.); (Q.Z.); (Y.G.); (H.Z.)
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yuqi Guo
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; (X.W.); (Q.Z.); (Y.G.); (H.Z.)
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Hengheng Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; (X.W.); (Q.Z.); (Y.G.); (H.Z.)
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Xiaoke Guo
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; (X.W.); (Q.Z.); (Y.G.); (H.Z.)
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
- Correspondence: (X.G.); (Q.Y.); (L.W.); Tel.: +86-025-83271351 (Q.Y.); +86-15261483858 (L.W.)
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; (X.W.); (Q.Z.); (Y.G.); (H.Z.)
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
- Correspondence: (X.G.); (Q.Y.); (L.W.); Tel.: +86-025-83271351 (Q.Y.); +86-15261483858 (L.W.)
| | - Lei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; (X.W.); (Q.Z.); (Y.G.); (H.Z.)
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
- Correspondence: (X.G.); (Q.Y.); (L.W.); Tel.: +86-025-83271351 (Q.Y.); +86-15261483858 (L.W.)
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A Microplate-Based Approach to Map Interactions between TDP-43 and α-Synuclein. J Clin Med 2022; 11:jcm11030573. [PMID: 35160025 PMCID: PMC8836581 DOI: 10.3390/jcm11030573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/15/2022] [Accepted: 01/18/2022] [Indexed: 11/30/2022] Open
Abstract
Trans-active response DNA-binding protein (TDP-43) is a multifunctional regulatory protein, whose abnormal deposition in neurons was linked to debilitating neurodegenerative diseases, such as amyotrophic lateral sclerosis, frontotemporal lobar degeneration, Limbic-predominant age-related TDP-43 encephalopathy, and Alzheimer’s disease with a secondary pathology. Several reports showed that TDP-43 proteinopathy as a comorbidity can form aggregates with other pathological proteins. The co-deposition of alpha synuclein and TDP-43 inclusions was previously reported in glial cells and by observing TDP-43 proteinopathy in Lewy body disease. In this study, it was hypothesized that alpha synuclein and TDP-43 may co-aggregate, resulting in comorbid synucleinopathy and TDP-43 proteinopathy. A solid-phase microplate-based immunoassay was used to map out the epitopes of anti-TDP-43 antibodies and locate the interaction of TDP-43 with α-synuclein. A region of the low complexity domain of TDP-43 (aa 311–314) was shown to interact with full-length α-synuclein. Conversely, full-length TDP-43 was shown to bind to the non-amyloid beta component of α-synuclein. Using in silico sequence-based prediction, the affinity and dissociation constant of full-length TDP-43 and α-synuclein were calculated to be −10.83 kcal/mol and 1.13 × 10−8, respectively. Taken together, this microplate-based method is convenient, economical, and rapid in locating antibody epitopes as well as interaction sites of two proteins.
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Wu K, Feng J, Lyu F, Xing F, Sharma S, Liu Y, Wu SY, Zhao D, Tyagi A, Deshpande RP, Pei X, Ruiz MG, Takahashi H, Tsuzuki S, Kimura T, Mo YY, Shiozawa Y, Singh R, Watabe K. Exosomal miR-19a and IBSP cooperate to induce osteolytic bone metastasis of estrogen receptor-positive breast cancer. Nat Commun 2021; 12:5196. [PMID: 34465793 PMCID: PMC8408156 DOI: 10.1038/s41467-021-25473-y] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 08/10/2021] [Indexed: 01/08/2023] Open
Abstract
Bone metastasis is an incurable complication of breast cancer. In advanced stages, patients with estrogen-positive tumors experience a significantly higher incidence of bone metastasis (>87%) compared to estrogen-negative patients (<56%). To understand the mechanism of this bone-tropism of ER+ tumor, and to identify liquid biopsy biomarkers for patients with high risk of bone metastasis, the secreted extracellular vesicles and cytokines from bone-tropic breast cancer cells are examined in this study. Both exosomal miR-19a and Integrin-Binding Sialoprotein (IBSP) are found to be significantly upregulated and secreted from bone-tropic ER+ breast cancer cells, increasing their levels in the circulation of patients. IBSP is found to attract osteoclast cells and create an osteoclast-enriched environment in the bone, assisting the delivery of exosomal miR-19a to osteoclast to induce osteoclastogenesis. Our findings reveal a mechanism by which ER+ breast cancer cells create a microenvironment favorable for colonization in the bone. These two secreted factors can also serve as effective biomarkers for ER+ breast cancer to predict their risks of bone metastasis. Furthermore, our screening of a natural compound library identifies chlorogenic acid as a potent inhibitor for IBSP-receptor binding to suppress bone metastasis of ER+ tumor, suggesting its preventive use for bone recurrence in ER+ patients.
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Affiliation(s)
- Kerui Wu
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Jiamei Feng
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
- Mammary Department, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Feng Lyu
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
- Department of Breast Surgery, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, Henan, China
| | - Fei Xing
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Sambad Sharma
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Yin Liu
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Shih-Ying Wu
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Dan Zhao
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Abhishek Tyagi
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | | - Xinhong Pei
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
- Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Marco Gabril Ruiz
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Hiroyuki Takahashi
- Department of Pathology, Jikei University School of Medicine, Minato City, Tokyo, Japan
| | - Shunsuke Tsuzuki
- Department of Pathology, Jikei University School of Medicine, Minato City, Tokyo, Japan
| | - Takahiro Kimura
- Department of Pathology, Jikei University School of Medicine, Minato City, Tokyo, Japan
| | - Yin-Yuan Mo
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Yusuke Shiozawa
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Ravi Singh
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Kounosuke Watabe
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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Vargas-Sanchez K, Losada-Barragán M, Mogilevskaya M, Novoa-Herrán S, Medina Y, Buendía-Atencio C, Lorett-Velásquez V, Martínez-Bernal J, Gonzalez-Reyes RE, Ramírez D, Petry KG. Screening for Interacting Proteins with Peptide Biomarker of Blood-Brain Barrier Alteration under Inflammatory Conditions. Int J Mol Sci 2021; 22:ijms22094725. [PMID: 33946948 PMCID: PMC8124558 DOI: 10.3390/ijms22094725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/25/2021] [Accepted: 04/26/2021] [Indexed: 02/06/2023] Open
Abstract
Neurodegenerative diseases are characterized by increased permeability of the blood-brain barrier (BBB) due to alterations in cellular and structural components of the neurovascular unit, particularly in association with neuroinflammation. A previous screening study of peptide ligands to identify molecular alterations of the BBB in neuroinflammation by phage-display, revealed that phage clone 88 presented specific binding affinity to endothelial cells under inflammatory conditions in vivo and in vitro. Here, we aimed to identify the possible target receptor of the peptide ligand 88 expressed under inflammatory conditions. A cross-link test between phage-peptide-88 with IL-1β-stimulated human hCMEC cells, followed by mass spectrometry analysis, was used to identify the target of peptide-88. We modeled the epitope-receptor molecular interaction between peptide-88 and its target by using docking simulations. Three proteins were selected as potential target candidates and tested in enzyme-linked immunosorbent assays with peptide-88: fibronectin, laminin subunit α5 and laminin subunit β-1. Among them, only laminin subunit β-1 presented measurable interaction with peptide-88. Peptide-88 showed specific interaction with laminin subunit β-1, highlighting its importance as a potential biomarker of the laminin changes that may occur at the BBB endothelial cells under pathological inflammation conditions.
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Affiliation(s)
- Karina Vargas-Sanchez
- Grupo de Neurociencia Translacional, Facultad de Medicina, Universidad de los Andes, Bogotá 111711, Colombia
- Correspondence: ; Tel.: +57-13102405706
| | - Monica Losada-Barragán
- Grupo de Biología Celular y Funcional e Ingeniería de Moléculas, Departamento de Biología, Universidad Antonio Nariño, Bogotá 110231, Colombia; (M.L.-B.); (Y.M.)
| | - Maria Mogilevskaya
- Grupo de Investigación GINIC-HUS, Universidad ECCI, Bogotá 111311, Colombia;
| | - Susana Novoa-Herrán
- Grupo de Investigación en Hormonas (Hormone Research Laboratory), Departamento de Química, Universidad Nacional de Colombia, Bogotá 111321, Colombia; or
- Grupo de Fisiología Molecular, Subdirección de Investigación Científica y Tecnológica, Instituto Nacional de Salud, Bogotá 111321, Colombia
| | - Yehidi Medina
- Grupo de Biología Celular y Funcional e Ingeniería de Moléculas, Departamento de Biología, Universidad Antonio Nariño, Bogotá 110231, Colombia; (M.L.-B.); (Y.M.)
| | - Cristian Buendía-Atencio
- Grupo de Investigación en Modelado y Computación Científica, Departamento de Química, Universidad Antonio Nariño, Bogotá 110231, Colombia;
| | - Vaneza Lorett-Velásquez
- Facultad de Medicina y Ciencias de la Salud, Universidad Militar Nueva Granada, Bogotá 110231, Colombia; (V.L.-V.); (J.M.-B.)
| | - Jessica Martínez-Bernal
- Facultad de Medicina y Ciencias de la Salud, Universidad Militar Nueva Granada, Bogotá 110231, Colombia; (V.L.-V.); (J.M.-B.)
| | - Rodrigo E. Gonzalez-Reyes
- Grupo de Investigación en Neurociencias (NeURos), Centro de Neurociencia Neurovitae-UR, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá 111711, Colombia;
| | - David Ramírez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, El llano Subercaseaux 2801, Santiago 8900000, Chile;
| | - Klaus G. Petry
- INSERM U1049 and U1029 Neuroinflammation and Angiogenesis Group, Bordeaux University, F33000 Bordeaux, France;
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9
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Cao T, Sujkowski A, Cobb T, Wessells RJ, Jin JP. The glutamic acid-rich-long C-terminal extension of troponin T has a critical role in insect muscle functions. J Biol Chem 2020; 295:3794-3807. [PMID: 32024695 PMCID: PMC7086023 DOI: 10.1074/jbc.ra119.012014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/03/2020] [Indexed: 12/12/2022] Open
Abstract
The troponin complex regulates the Ca2+ activation of myofilaments during striated muscle contraction and relaxation. Troponin genes emerged 500-700 million years ago during early animal evolution. Troponin T (TnT) is the thin-filament-anchoring subunit of troponin. Vertebrate and invertebrate TnTs have conserved core structures, reflecting conserved functions in regulating muscle contraction, and they also contain significantly diverged structures, reflecting muscle type- and species-specific adaptations. TnT in insects contains a highly-diverged structure consisting of a long glutamic acid-rich C-terminal extension of ∼70 residues with unknown function. We found here that C-terminally truncated Drosophila TnT (TpnT-CD70) retains binding of tropomyosin, troponin I, and troponin C, indicating a preserved core structure of TnT. However, the mutant TpnTCD70 gene residing on the X chromosome resulted in lethality in male flies. We demonstrate that this X-linked mutation produces dominant-negative phenotypes, including decreased flying and climbing abilities, in heterozygous female flies. Immunoblot quantification with a TpnT-specific mAb indicated expression of TpnT-CD70 in vivo and normal stoichiometry of total TnT in myofilaments of heterozygous female flies. Light and EM examinations revealed primarily normal sarcomere structures in female heterozygous animals, whereas Z-band streaming could be observed in the jump muscle of these flies. Although TpnT-CD70-expressing flies exhibited lower resistance to cardiac stress, their hearts were significantly more tolerant to Ca2+ overloading induced by high-frequency electrical pacing. Our findings suggest that the Glu-rich long C-terminal extension of insect TnT functions as a myofilament Ca2+ buffer/reservoir and is potentially critical to the high-frequency asynchronous contraction of flight muscles.
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Affiliation(s)
- Tianxin Cao
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201
| | - Alyson Sujkowski
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201
| | - Tyler Cobb
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201
| | - Robert J Wessells
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201
| | - Jian-Ping Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201
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10
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Wong S, Feng HZ, Jin JP. The evolutionarily conserved C-terminal peptide of troponin I is an independently configured regulatory structure to function as a myofilament Ca 2+-desensitizer. J Mol Cell Cardiol 2019; 136:42-52. [PMID: 31505197 DOI: 10.1016/j.yjmcc.2019.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/04/2019] [Accepted: 09/06/2019] [Indexed: 12/22/2022]
Abstract
The C-terminal end segment of troponin subunit I (TnI) is a structure highly conserved among the three muscle type-specific isoforms and across vertebrate species. Partial deletion or point mutation in this segment impairs cardiac muscle relaxation. In the present study, we characterized the C-terminal 27 amino acid peptide of human cardiac TnI (HcTnI-C27) for its role in modulating muscle contractility. Biologically or chemically synthesized HcTnI-C27 peptide retains an epitope structure in physiological solutions similarly to that in intact TnI as recognized by an anti-TnI C-terminus monoclonal antibody (mAb TnI-1). Protein binding studies found that HcTnI-C27 retains the binding affinity for tropomyosin as previously shown with intact cardiac TnI. A restrictive cardiomyopathy mutation R192H in this segment abolishes the bindings to mAb TnI-1 and tropomyosin, demonstrating a pathogenic loss of function. Contractility studies using skinned muscle preparations demonstrated that addition of HcTnI-C27 peptide reduces the Ca2+-sensitivity of myofibrils without decreasing maximum force production. The results indicate that the C-terminal end segment of TnI is a regulatory element of troponin, which retains the native configuration in the form of free peptide to confer an effect on myofilament Ca2+-desensitization. Without negative inotropic impact, this short peptide may be developed into a novel reagent to selectively facilitate cardiac muscle relaxation at the activated state as a potential treatment for heart failure.
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Affiliation(s)
- Sienna Wong
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA
| | - Han-Zhong Feng
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA
| | - J-P Jin
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA.
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11
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Elevated levels of Secreted-Frizzled-Related-Protein 1 contribute to Alzheimer's disease pathogenesis. Nat Neurosci 2019; 22:1258-1268. [PMID: 31308530 DOI: 10.1038/s41593-019-0432-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 05/20/2019] [Indexed: 02/07/2023]
Abstract
The deposition of aggregated amyloid-β peptides derived from the pro-amyloidogenic processing of the amyloid precurson protein (APP) into characteristic amyloid plaques (APs) is distinctive to Alzheimer's disease (AD). Alternative APP processing via the metalloprotease ADAM10 prevents amyloid-β formation. We tested whether downregulation of ADAM10 activity by its secreted endogenous inhibitor secreted-frizzled-related protein 1 (SFRP1) is a common trait of sporadic AD. We demonstrate that SFRP1 is significantly increased in the brain and cerebrospinal fluid of patients with AD, accumulates in APs and binds to amyloid-β, hindering amyloid-β protofibril formation. Sfrp1 overexpression in an AD-like mouse model anticipates the appearance of APs and dystrophic neurites, whereas its genetic inactivation or the infusion of α-SFRP1-neutralizing antibodies favors non-amyloidogenic APP processing. Decreased Sfrp1 function lowers AP accumulation, improves AD-related histopathological traits and prevents long-term potentiation loss and cognitive deficits. Our study unveils SFRP1 as a crucial player in AD pathogenesis and a promising AD therapeutic target.
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12
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Lim HJ, Jang HJ, Bak SG, Lee S, Lee SW, Lee KM, Lee SJ, Rho MC. In vitro inhibitory effects of cirsiliol on IL-6-induced STAT3 activation through anti-inflammatory activity. Bioorg Med Chem Lett 2019; 29:1586-1592. [DOI: 10.1016/j.bmcl.2019.04.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/22/2019] [Accepted: 04/30/2019] [Indexed: 10/26/2022]
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13
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Peterson YK, Nasarre P, Bonilla IV, Hilliard E, Samples J, Morinelli TA, Hill EG, Klauber-DeMore N. Frizzled-5: a high affinity receptor for secreted frizzled-related protein-2 activation of nuclear factor of activated T-cells c3 signaling to promote angiogenesis. Angiogenesis 2017; 20:615-628. [PMID: 28840375 DOI: 10.1007/s10456-017-9574-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 08/15/2017] [Indexed: 11/30/2022]
Abstract
Secreted frizzled-related protein 2 (SFRP2) is a pro-angiogenic factor expressed in the vasculature of a wide variety of human tumors, and modulates angiogenesis via the calcineurin-dependent nuclear factor of activated T-cells cytoplasmic 3 (NFATc3) pathway in endothelial cells. However, until now, SFRP2 receptor for this pathway was unknown. In the present study, we first used amino acid alignments and molecular modeling to demonstrate that SFRP2 interaction with frizzled-5 (FZD5) is typical of Wnt/FZD family members. To confirm this interaction, we performed co-immunofluorescence, co-immunoprecipitation, and ELISA binding assays, which demonstrated SFRP2/FZD5 binding. Functional knock-down studies further revealed that FZD5 is necessary for SFRP2-induced tube formation and intracellular calcium flux in endothelial cells. Using protein analysis on endothelial cell nuclear extracts, we also discovered that FZD5 is required for SFRP2-induced activation of NFATc3. Our novel findings reveal that FZD5 is a receptor for SFRP2 and mediates SFRP2-induced angiogenesis via calcineurin/NFATc3 pathway in endothelial cells.
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Affiliation(s)
- Yuri K Peterson
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Patrick Nasarre
- Department of Surgery, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Ingrid V Bonilla
- Department of Surgery, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Eleanor Hilliard
- Department of Surgery, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Jennifer Samples
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Thomas A Morinelli
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Elizabeth G Hill
- Department of Public Health Science, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Nancy Klauber-DeMore
- Department of Surgery, Medical University of South Carolina, Charleston, SC, 29425, USA.
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14
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Powers KT, Washington MT. Analyzing the Catalytic Activities and Interactions of Eukaryotic Translesion Synthesis Polymerases. Methods Enzymol 2017; 592:329-356. [PMID: 28668126 DOI: 10.1016/bs.mie.2017.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Translesion synthesis is the process by which nonclassical DNA polymerases bypass DNA damage during DNA replication. Cells possess a variety of nonclassical polymerases, each one is specific for incorporating nucleotides opposite to one or more closely related DNA lesions, called its cognate lesions. In this chapter, we discuss a variety of approaches for probing the catalytic activities and the protein-protein interactions of nonclassical polymerases. With respect to their catalytic activities, we discuss polymerase assays, steady-state kinetics, and presteady-state kinetics. With respect to their interactions, we discuss qualitative binding assays such as enzyme-linked immunosorbent assays and coimmunoprecipitation; quantitative binding assays such as isothermal titration calorimetry, surface plasmon resonance, and nuclear magnetic resonance spectroscopy; and single-molecule binding assays such as total internal reflection fluorescence microscopy. We focus on how nonclassical polymerases accommodate their cognate lesions during nucleotide incorporation and how the most appropriate nonclassical polymerase is selected for bypassing a given lesion.
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Affiliation(s)
- Kyle T Powers
- Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - M Todd Washington
- Carver College of Medicine, University of Iowa, Iowa City, IA, United States.
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15
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Salhi HE, Hassel NC, Siddiqui JK, Brundage EA, Ziolo MT, Janssen PML, Davis JP, Biesiadecki BJ. Myofilament Calcium Sensitivity: Mechanistic Insight into TnI Ser-23/24 and Ser-150 Phosphorylation Integration. Front Physiol 2016; 7:567. [PMID: 28018230 PMCID: PMC5156683 DOI: 10.3389/fphys.2016.00567] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/08/2016] [Indexed: 11/14/2022] Open
Abstract
Troponin I (TnI) is a major regulator of cardiac muscle contraction and relaxation. During physiological and pathological stress, TnI is differentially phosphorylated at multiple residues through different signaling pathways to match cardiac function to demand. The combination of these TnI phosphorylations can exhibit an expected or unexpected functional integration, whereby the function of two phosphorylations are different than that predicted from the combined function of each individual phosphorylation alone. We have shown that TnI Ser-23/24 and Ser-150 phosphorylation exhibit functional integration and are simultaneously increased in response to cardiac stress. In the current study, we investigated the functional integration of TnI Ser-23/24 and Ser-150 to alter cardiac contraction. We hypothesized that Ser-23/24 and Ser-150 phosphorylation each utilize distinct molecular mechanisms to alter the TnI binding affinity within the thin filament. Mathematical modeling predicts that Ser-23/24 and Ser-150 phosphorylation affect different TnI affinities within the thin filament to distinctly alter the Ca2+-binding properties of troponin. Protein binding experiments validate this assertion by demonstrating pseudo-phosphorylated Ser-150 decreases the affinity of isolated TnI for actin, whereas Ser-23/24 pseudo-phosphorylation is not different from unphosphorylated. Thus, our data supports that TnI Ser-23/24 affects TnI-TnC binding, while Ser-150 phosphorylation alters TnI-actin binding. By measuring force development in troponin-exchanged skinned myocytes, we demonstrate that the Ca2+ sensitivity of force is directly related to the amount of phosphate present on TnI. Furthermore, we demonstrate that Ser-150 pseudo-phosphorylation blunts Ser-23/24-mediated decreased Ca2+-sensitive force development whether on the same or different TnI molecule. Therefore, TnI phosphorylations can integrate across troponins along the myofilament. These data demonstrate that TnI Ser-23/24 and Ser-150 phosphorylation regulates muscle contraction in part by modulating different TnI interactions in the thin filament and it is the combination of these differential mechanisms that provides understanding of their functional integration.
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Affiliation(s)
| | | | | | | | | | | | | | - Brandon J. Biesiadecki
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State UniversityColumbus, OH, USA
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16
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Amarasinghe C, Hossain MM, Jin JP. Functional Basis of Three New Recessive Mutations of Slow Skeletal Muscle Troponin T Found in Non-Amish TNNT1 Nemaline Myopathies. Biochemistry 2016; 55:4560-7. [DOI: 10.1021/acs.biochem.6b00577] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Chinthaka Amarasinghe
- Department
of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - M. Moazzem Hossain
- Department
of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - J.-P. Jin
- Department
of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
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17
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Zhou M, Li Q, Wang R. Current Experimental Methods for Characterizing Protein-Protein Interactions. ChemMedChem 2016; 11:738-56. [PMID: 26864455 PMCID: PMC7162211 DOI: 10.1002/cmdc.201500495] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/08/2016] [Indexed: 12/14/2022]
Abstract
Protein molecules often interact with other partner protein molecules in order to execute their vital functions in living organisms. Characterization of protein-protein interactions thus plays a central role in understanding the molecular mechanism of relevant protein molecules, elucidating the cellular processes and pathways relevant to health or disease for drug discovery, and charting large-scale interaction networks in systems biology research. A whole spectrum of methods, based on biophysical, biochemical, or genetic principles, have been developed to detect the time, space, and functional relevance of protein-protein interactions at various degrees of affinity and specificity. This article presents an overview of these experimental methods, outlining the principles, strengths and limitations, and recent developments of each type of method.
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Affiliation(s)
- Mi Zhou
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China
| | - Qing Li
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China
| | - Renxiao Wang
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China.
- State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Macau, 999078, People's Republic of China.
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18
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Boehm EM, Powers KT, Kondratick CM, Spies M, Houtman JCD, Washington MT. The Proliferating Cell Nuclear Antigen (PCNA)-interacting Protein (PIP) Motif of DNA Polymerase η Mediates Its Interaction with the C-terminal Domain of Rev1. J Biol Chem 2016; 291:8735-44. [PMID: 26903512 DOI: 10.1074/jbc.m115.697938] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Indexed: 11/06/2022] Open
Abstract
Y-family DNA polymerases, such as polymerase η, polymerase ι, and polymerase κ, catalyze the bypass of DNA damage during translesion synthesis. These enzymes are recruited to sites of DNA damage by interacting with the essential replication accessory protein proliferating cell nuclear antigen (PCNA) and the scaffold protein Rev1. In most Y-family polymerases, these interactions are mediated by one or more conserved PCNA-interacting protein (PIP) motifs that bind in a hydrophobic pocket on the front side of PCNA as well as by conserved Rev1-interacting region (RIR) motifs that bind in a hydrophobic pocket on the C-terminal domain of Rev1. Yeast polymerase η, a prototypical translesion synthesis polymerase, binds both PCNA and Rev1. It possesses a single PIP motif but not an RIR motif. Here we show that the PIP motif of yeast polymerase η mediates its interactions both with PCNA and with Rev1. Moreover, the PIP motif of polymerase η binds in the hydrophobic pocket on the Rev1 C-terminal domain. We also show that the RIR motif of human polymerase κ and the PIP motif of yeast Msh6 bind both PCNA and Rev1. Overall, these findings demonstrate that PIP motifs and RIR motifs have overlapping specificities and can interact with both PCNA and Rev1 in structurally similar ways. These findings also suggest that PIP motifs are a more versatile protein interaction motif than previously believed.
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Affiliation(s)
| | | | | | | | - Jon C D Houtman
- Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
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19
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Amarasinghe C, Jin JP. N-Terminal Hypervariable Region of Muscle Type Isoforms of Troponin T Differentially Modulates the Affinity of Tropomyosin-Binding Site 1. Biochemistry 2015; 54:3822-30. [DOI: 10.1021/acs.biochem.5b00348] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Chinthaka Amarasinghe
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - J.-P. Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
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20
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Akhter S, Jin JP. Distinct conformational and functional effects of two adjacent pathogenic mutations in cardiac troponin I at the interface with troponin T. FEBS Open Bio 2015; 5:64-75. [PMID: 25685665 PMCID: PMC4325132 DOI: 10.1016/j.fob.2015.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 12/31/2014] [Accepted: 01/02/2015] [Indexed: 11/29/2022] Open
Abstract
Mutations in the TnT-interface of cardiac TnI cause cardiomyopathies. Mutations A117G and K118C resulted in distinct changes in protein conformation. K118C, but not A117G, decreased the binding affinity for TnT. K118C decreased binding affinity for TnC in a Ca2+-dependent manner – A117G had a similar but less profound effect. PKA treatment or N-terminal truncation produces similar changes in cardiac TnI.
The α-helix in troponin I (TnI) at the interface with troponin T (TnT) is a highly conserved structure. A point mutation in this region, A116G, was found in human cardiac TnI in a case of cardiomyopathy. An adjacent dominantly negative mutation found in turkey cardiac TnI (R111C, equivalent to K117C in human and K118C in mouse) decreased diastolic function and blunted beta-adrenergic response in transgenic mice. To investigate the functional importance of the TnI–TnT interface and pathological impact of the cardiac TnI mutations, we engineered K118C and A117G mutations in mouse cardiac TnI for functional studies. Despite their adjacent locations, A117G substitution results in faster mobility of cardiac TnI in SDS–PAGE whereas K118C decreases gel mobility, indicating significant and distinct changes in overall protein conformation. Consistently, monoclonal antibody epitope analysis demonstrated distinct local and remote conformational alterations in the two mutant proteins. Protein binding assays showed that K118C, but not A117G, decreased the relative binding affinity of cardiac TnI for TnT. K118C mutation decreased binding affinity for troponin C in a Ca2+-dependent manner, whereas A117G had a similar but less profound effect. Protein kinase A phosphorylation or truncation to remove the cardiac specific N-terminal extension of cardiac TnI resulted in similar conformational changes in the region interfacing with TnT and minimized the functional impacts of the mutations. The data demonstrate potent conformational and functional impacts of the TnT-interfacing helix in TnI and suggest a role of the N-terminal extension of cardiac TnI in modulating TnI–TnT interface functions.
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Key Words
- BSA, bovine serum albumin
- Cardiac muscle
- ELISA, enzyme linked immunosorbent assay
- McTnI, wild type mouse cardiac TnI
- McTnI-ND, N-terminal truncated mouse cardiac TnI
- McTnI-NDA117G, N-terminal truncated McTnIA117G
- McTnI-NDK118C, N-terminal truncated McTnIK118C
- McTnIA117G, mouse cardiac TnI A117G mutation
- McTnIK118C, mouse cardiac TnI K118C mutation
- PKA, protein kinase A
- Protein conformation
- TnC, troponin C
- TnI, troponin I
- TnT, troponin T
- Troponin
- Troponin I mutation
- Troponin I–Troponin T interface
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Affiliation(s)
- Shirin Akhter
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - J-P Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
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21
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Vadivel K, Ponnuraj SM, Kumar Y, Zaiss AK, Bunce MW, Camire RM, Wu L, Evseenko D, Herschman HR, Bajaj MS, Bajaj SP. Platelets contain tissue factor pathway inhibitor-2 derived from megakaryocytes and inhibits fibrinolysis. J Biol Chem 2014; 289:31647-61. [PMID: 25262870 DOI: 10.1074/jbc.m114.569665] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tissue factor pathway inhibitor-2 (TFPI-2) is a homologue of TFPI-1 and contains three Kunitz-type domains and a basic C terminus region. The N-terminal domain of TFPI-2 is the only inhibitory domain, and it inhibits plasma kallikrein, factor XIa, and plasmin. However, plasma TFPI-2 levels are negligible (≤20 pM) in the context of influencing clotting or fibrinolysis. Here, we report that platelets contain significant amounts of TFPI-2 derived from megakaryocytes. We employed RT-PCR, Western blotting, immunohistochemistry, and confocal microscopy to determine that platelets, MEG-01 megakaryoblastic cells, and bone marrow megakaryocytes contain TFPI-2. ELISA data reveal that TFPI-2 binds factor V (FV) and partially B-domain-deleted FV (FV-1033) with K(d) ~9 nM and binds FVa with K(d) ~100 nM. Steady state analysis of surface plasmon resonance data reveal that TFPI-2 and TFPI-1 bind FV-1033 with K(d) ~36-48 nM and bind FVa with K(d) ~252-456 nM. Further, TFPI-1 (but not TFPI-1161) competes with TFPI-2 in binding to FV. These data indicate that the C-terminal basic region of TFPI-2 is similar to that of TFPI-1 and plays a role in binding to the FV B-domain acidic region. Using pull-down assays and Western blots, we show that TFPI-2 is associated with platelet FV/FVa. TFPI-2 (~7 nM) in plasma of women at the onset of labor is also, in part, associated with FV. Importantly, TFPI-2 in platelets and in plasma of pregnant women inhibits FXIa and tissue-type plasminogen activator-induced clot fibrinolysis. In conclusion, TFPI-2 in platelets from normal or pregnant subjects and in plasma from pregnant women binds FV/Va and regulates intrinsic coagulation and fibrinolysis.
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Affiliation(s)
| | | | - Yogesh Kumar
- From the UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery
| | - Anne K Zaiss
- the Department of Molecular and Medical Pharmacology
| | - Matthew W Bunce
- the Department of Pediatrics, Division of Hematology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Rodney M Camire
- the Department of Pediatrics, Division of Hematology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Ling Wu
- From the UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery
| | - Denis Evseenko
- From the UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery
| | - Harvey R Herschman
- the Department of Molecular and Medical Pharmacology, the Molecular Biology Institute, UCLA, Los Angeles, California 90095 and
| | - Madhu S Bajaj
- the Department of Medicine, Division of Pulmonology and Critical Care, and
| | - S Paul Bajaj
- From the UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery, the Molecular Biology Institute, UCLA, Los Angeles, California 90095 and
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