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Kwak H, Kim MS, Kim S, Kim J, Aoki Y, Chung SJ, Nam HJ, Lee W. Kinetic modeling of the plasma pharmacokinetic profiles of ADAMTS13 fragment and its Fc-fusion counterpart in mice. Front Pharmacol 2024; 15:1352842. [PMID: 38590637 PMCID: PMC10999626 DOI: 10.3389/fphar.2024.1352842] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 03/13/2024] [Indexed: 04/10/2024] Open
Abstract
Introduction: Fusion of the fragment crystallizable (Fc) to protein therapeutics is commonly used to extend the circulation time by enhancing neonatal Fc-receptor (FcRn)-mediated endosomal recycling and slowing renal clearance. This study applied kinetic modeling to gain insights into the cellular processing contributing to the observed pharmacokinetic (PK) differences between the novel recombinant ADAMTS13 fragment (MDTCS) and its Fc-fusion protein (MDTCS-Fc). Methods: For MDTCS and MDTCS-Fc, their plasma PK profiles were obtained at two dose levels following intravenous administration of the respective proteins to mice. The plasma PK profiles of MDTCS were fitted to a kinetic model with three unknown protein-dependent parameters representing the fraction recycled (FR) and the rate constants for endocytosis (kup, for the uptake into the endosomes) and for the transfer from the plasma to the interstitial fluid (kpi). For MDTCS-Fc, the model was modified to include an additional parameter for binding to FcRn. Parameter optimization was done using the Cluster Gauss-Newton Method (CGNM), an algorithm that identifies multiple sets of approximate solutions ("accepted" parameter sets) to nonlinear least-squares problems. Results: As expected, the kinetic modeling results yielded the FR of MDTCS-Fc to be 2.8-fold greater than that of MDTCS (0.8497 and 0.3061, respectively). In addition, MDTCS-Fc was predicted to undergo endocytosis (the uptake into the endosomes) at a slower rate than MDTCS. Sensitivity analyses identified the association rate constant (kon) between MDTCS-Fc and FcRn as a potentially important factor influencing the plasma half-life in vivo. Discussion: Our analyses suggested that Fc fusion to MDTCS leads to changes in not only the FR but also the uptake into the endosomes, impacting the systemic plasma PK profiles. These findings may be used to develop recombinant protein therapeutics with extended circulation time.
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Affiliation(s)
- Heechun Kwak
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
- Discovery Unit, Research and Early Development Department, GC Biopharma Corp, Yongin-si, Republic of Korea
| | - Min-Soo Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Suyong Kim
- Discovery Unit, Research and Early Development Department, GC Biopharma Corp, Yongin-si, Republic of Korea
| | - Jiyoung Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Yasunori Aoki
- Laboratory of Quantitative System Pharmacokinetics/Pharmacodynamics, Josai International University, Tokyo, Japan
- Drug Metabolism and Pharmacokinetics, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Suk-Jae Chung
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyun-Ja Nam
- Discovery Unit, Research and Early Development Department, GC Biopharma Corp, Yongin-si, Republic of Korea
| | - Wooin Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
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2
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Yoo KY, Jung SY, Hwang SH, Lee SM, Park JH, Nam HJ. Global hemostatic assay of different target procoagulant activities of factor VIII and factor IX. Blood Res 2018; 53:41-48. [PMID: 29662861 PMCID: PMC5898993 DOI: 10.5045/br.2018.53.1.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 06/26/2017] [Revised: 10/11/2017] [Accepted: 10/29/2017] [Indexed: 11/23/2022] Open
Abstract
Background Korean National Health Insurance reimburses factor VIII (FVIII) and factor IX (FIX) clotting factor concentrate (CFC) infusions to discrepant activity levels, allowing elevation of FVIII activity to 60 IU/dL and FIX to 40 IU/dL. We aimed to assess hemostatic response to these target levels using global hemostatic assays. Methods We enrolled 34 normal healthy men, 34 patients with hemophilia A, and 36 with hemophilia B, with residual factor activity of 3 IU/dL or less and without inhibitors. Patients with hemophilia A and B received injected CFCs according to reimbursement guidelines. Fifteen minutes after injection, we assessed hemostatic response with global hemostatic assays: thrombin generation assay (TGA), thromboelastography (TEG), and clot waveform analysis (CWA). Results Normal healthy men and patients with hemophilia A and B were 36.7, 37.2, and 35.1 years old, respectively. FVIII and recombinant FIX concentrate doses were 28.8 IU/kg and 43.6 IU/kg. Post-infusion FVIII activity rose from 0.5 IU/dL to 69.4 IU/dL, while FIX activity rose from 1.4 IU/dL to 46.8 IU/dL. Post-infusion peak thrombin concentrations in hemophilia A and B were 116.6 nM/L and 76.4 nM/L (P<0.001). Post-infusion endogenous thrombin potential (ETP) in hemophilia A and B was 1349.8 nM/min and 915.6 nM (P<0.001). TEG index of hemophilia A and B was 0.11 and −0.51 (P=0.006). Conclusion Current reimbursed doses for FIX concentrates are insufficient to achieve hemostatic responses comparable to those after reimbursed doses for FVIII concentrates in terms of peak thrombin concentration, ETP, and TEG index.
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Affiliation(s)
| | | | - Sung-Ho Hwang
- Mogam Institute for Biomedical Research, Yongin, Korea
| | - Su-Min Lee
- Mogam Institute for Biomedical Research, Yongin, Korea
| | - Jong-Ho Park
- Mogam Institute for Biomedical Research, Yongin, Korea
| | - Hyun-Ja Nam
- Mogam Institute for Biomedical Research, Yongin, Korea
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3
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Maskey RS, Flatten KS, Sieben CJ, Peterson KL, Baker DJ, Nam HJ, Kim MS, Smyrk TC, Kojima Y, Machida Y, Santiago A, van Deursen JM, Kaufmann SH, Machida YJ. Spartan deficiency causes accumulation of Topoisomerase 1 cleavage complexes and tumorigenesis. Nucleic Acids Res 2017; 45:4564-4576. [PMID: 28199696 PMCID: PMC5416836 DOI: 10.1093/nar/gkx107] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/06/2017] [Indexed: 11/30/2022] Open
Abstract
Germline mutations in SPRTN cause Ruijs–Aalfs syndrome (RJALS), a disorder characterized by genome instability, progeria and early onset hepatocellular carcinoma. Spartan, the protein encoded by SPRTN, is a nuclear metalloprotease that is involved in the repair of DNA–protein crosslinks (DPCs). Although Sprtn hypomorphic mice recapitulate key progeroid phenotypes of RJALS, whether this model expressing low amounts of Spartan is prone to DPC repair defects and spontaneous tumors is unknown. Here, we showed that the livers of Sprtn hypomorphic mice accumulate DPCs containing Topoisomerase 1 covalently linked to DNA. Furthermore, these mice exhibited DNA damage, aneuploidy and spontaneous tumorigenesis in the liver. Collectively, these findings provide evidence that partial loss of Spartan impairs DPC repair and tumor suppression.
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Affiliation(s)
- Reeja S Maskey
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Karen S Flatten
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Cynthia J Sieben
- Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Kevin L Peterson
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Darren J Baker
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Hyun-Ja Nam
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Myoung Shin Kim
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Thomas C Smyrk
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Yusuke Kojima
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Yuka Machida
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Annyoceli Santiago
- Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Jan M van Deursen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Scott H Kaufmann
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
| | - Yuichi J Machida
- Department of Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
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Kanakkanthara A, Jeganathan KB, Limzerwala JF, Baker DJ, Hamada M, Nam HJ, van Deursen WH, Hamada N, Naylor RM, Becker NA, Davies BA, van Ree JH, Mer G, Shapiro VS, Maher LJ, Katzmann DJ, van Deursen JM. Cyclin A2 is an RNA binding protein that controls Mre11 mRNA translation. Science 2017; 353:1549-1552. [PMID: 27708105 DOI: 10.1126/science.aaf7463] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/29/2016] [Indexed: 12/23/2022]
Abstract
Cyclin A2 activates the cyclin-dependent kinases Cdk1 and Cdk2 and is expressed at elevated levels from S phase until early mitosis. We found that mutant mice that cannot elevate cyclin A2 are chromosomally unstable and tumor-prone. Underlying the chromosomal instability is a failure to up-regulate the meiotic recombination 11 (Mre11) nuclease in S phase, which leads to impaired resolution of stalled replication forks, insufficient repair of double-stranded DNA breaks, and improper segregation of sister chromosomes. Unexpectedly, cyclin A2 controlled Mre11 abundance through a C-terminal RNA binding domain that selectively and directly binds Mre11 transcripts to mediate polysome loading and translation. These data reveal cyclin A2 as a mechanistically diverse regulator of DNA replication combining multifaceted kinase-dependent functions with a kinase-independent, RNA binding-dependent role that ensures adequate repair of common replication errors.
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Affiliation(s)
- Arun Kanakkanthara
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Karthik B Jeganathan
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jazeel F Limzerwala
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Darren J Baker
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Masakazu Hamada
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Hyun-Ja Nam
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Naomi Hamada
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Ryan M Naylor
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Nicole A Becker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Brian A Davies
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Janine H van Ree
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Georges Mer
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | | | - L James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - David J Katzmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Jan M van Deursen
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA. Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
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van Ree JH, Nam HJ, van Deursen JM. Mitotic kinase cascades orchestrating timely disjunction and movement of centrosomes maintain chromosomal stability and prevent cancer. Chromosome Res 2016; 24:67-76. [PMID: 26615533 DOI: 10.1007/s10577-015-9501-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Centrosomes are microtubule-organizing centers that duplicate in S phase to form bipolar spindles that separate duplicated chromosomes faithfully into two daughter cells during cell division. Recent studies show that proper timing of centrosome dynamics, the disjunction and movement of centrosomes, is tightly linked to spindle symmetry, correct microtubule-kinetochore attachment, and chromosome segregation. Here, we review mechanisms that regulate centrosome dynamics, with emphasis on the roles of key mitotic kinases in the proper timing of centrosome dynamics and how aberrancies in these processes may cause chromosomal instability and cancer.
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Affiliation(s)
- Janine H van Ree
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Hyun-Ja Nam
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Jan M van Deursen
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA. .,Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA.
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Lee SB, Kim JJ, Nam HJ, Gao B, Yin P, Qin B, Yi SY, Ham H, Evans D, Kim SH, Zhang J, Deng M, Liu T, Zhang H, Billadeau DD, Wang L, Giaime E, Shen J, Pang YP, Jen J, van Deursen JM, Lou Z. Parkin Regulates Mitosis and Genomic Stability through Cdc20/Cdh1. Mol Cell 2015; 60:21-34. [PMID: 26387737 PMCID: PMC4592523 DOI: 10.1016/j.molcel.2015.08.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [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: 02/19/2015] [Revised: 06/04/2015] [Accepted: 08/12/2015] [Indexed: 01/04/2023]
Abstract
Mutations in the E3 ubiquitin ligase Parkin have been linked to familial Parkinson's disease. Parkin has also been implicated in mitosis through mechanisms that are unclear. Here we show that Parkin interacts with anaphase promoting complex/cyclosome (APC/C) coactivators Cdc20 and Cdh1 to mediate the degradation of several key mitotic regulators independent of APC/C. We demonstrate that ordered progression through mitosis is orchestrated by two distinct E3 ligases through the shared use of Cdc20 and Cdh1. Furthermore, Parkin is phosphorylated and activated by polo-like kinase 1 (Plk1) during mitosis. Parkin deficiency results in overexpression of its substrates, mitotic defects, genomic instability, and tumorigenesis. These results suggest that the Parkin-Cdc20/Cdh1 complex is an important regulator of mitosis.
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Affiliation(s)
- Seung Baek Lee
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Jung Jin Kim
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Hyun-Ja Nam
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Bowen Gao
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Ping Yin
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Bo Qin
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Sang-Yeop Yi
- Department of Pathology, International St. Mary's Hospital, College of Medicine, Catholic Kwandong University, Incheon 404 834, Republic of Korea
| | - Hyoungjun Ham
- Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA
- Mayo Graduate School, Mayo Clinic, Rochester, MN 55905, USA
| | - Debra Evans
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
- Mayo Graduate School, Mayo Clinic, Rochester, MN 55905, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Sun-Hyun Kim
- Department of Family Medicine, International St. Mary's Hospital, College of Medicine, Catholic Kwandong University, Incheon 404 834, Republic of Korea
| | - Jun Zhang
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Min Deng
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Tongzheng Liu
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Haoxing Zhang
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Daniel D. Billadeau
- Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Oncology Research and Schulze Center for Novel Therapeutics, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Emilie Giaime
- Center for Neurologic Diseases, Department of Neurology, Brigham & Women's Hospital, Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
| | - Jie Shen
- Center for Neurologic Diseases, Department of Neurology, Brigham & Women's Hospital, Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
| | - Yuan-Ping Pang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Jin Jen
- Division of Pulmonary and Critical Care Medicine, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA, Mayo Clinic, Rochester, MN 55905, USA
| | - Jan M. van Deursen
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhenkun Lou
- Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
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Park M, Lee BS, Jeon SH, Nam HJ, Lee G, Kim CH, Cho H, Lee JH. A novel isoform of met receptor tyrosine kinase blocks hepatocyte growth factor/Met signaling and stimulates skeletal muscle cell differentiation. J Biol Chem 2014; 290:1804-17. [PMID: 25471370 DOI: 10.1074/jbc.m114.596957] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatocyte growth factor (HGF) and its receptor, Met, regulate skeletal muscle differentiation. In the present study, we identified a novel alternatively spliced isoform of Met lacking exon 13 (designated Δ13Met), which is expressed mainly in human skeletal muscle. Alternative splicing yielded a truncated Met having extracellular domain only, suggesting an inhibitory role. Indeed, Δ13Met expression led to a decrease in HGF-induced tyrosine phosphorylation of Met and ERK phosphorylation, as well as cell proliferation and migration via sequestration of HGF. Interestingly, in human primary myoblasts undergoing differentiation, Δ13Met mRNA and protein levels were rapidly increased, concomitantly with a decrease in wild type Met mRNA and protein. Inhibition of Δ13Met with siRNA led to a decreased differentiation, whereas its overexpression potentiated differentiation of human primary myoblasts. Furthermore, in notexin-induced mouse injury model, exogenous Δ13Met expression enhanced regeneration of skeletal muscle, further confirming a stimulatory role of the isoform in muscle cell differentiation. In summary, we identified a novel alternatively spliced inhibitory isoform of Met that stimulates muscle cell differentiation, which confers a new means to control muscle differentiation and/or regeneration.
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Affiliation(s)
- Minseon Park
- From the Departments of Biochemistry and Molecular Biology
| | | | - Soung-Hoo Jeon
- From the Departments of Biochemistry and Molecular Biology
| | - Hyun-Ja Nam
- From the Departments of Biochemistry and Molecular Biology
| | - Gwang Lee
- Physiology, Ajou University School of Medicine, Yeongtong-gu, Suwon 443-721, Korea
| | | | - Hyeseong Cho
- From the Departments of Biochemistry and Molecular Biology
| | - Jae-Ho Lee
- From the Departments of Biochemistry and Molecular Biology,
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8
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Nam HJ, Naylor RM, van Deursen JM. Centrosome dynamics as a source of chromosomal instability. Trends Cell Biol 2014; 25:65-73. [PMID: 25455111 DOI: 10.1016/j.tcb.2014.10.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 01/03/2023]
Abstract
Accurate segregation of duplicated chromosomes between two daughter cells depends on bipolar spindle formation, a metaphase state in which sister kinetochores are attached to microtubules emanating from opposite spindle poles. To ensure bi-orientation, cells possess surveillance systems that safeguard against microtubule-kinetochore attachment defects, including the spindle assembly checkpoint and the error correction machinery. However, recent developments have identified centrosome dynamics--that is, centrosome disjunction and poleward movement of duplicated centrosomes--as a central target for deregulation of bi-orientation in cancer cells. In this review, we discuss novel insights into the mechanisms that underlie centrosome dynamics and discuss how these mechanisms are perturbed in cancer cells to drive chromosome mis-segregation and advance neoplastic transformation.
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Affiliation(s)
- Hyun-Ja Nam
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Ryan M Naylor
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Jan M van Deursen
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
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Abstract
Cyclins B1 and B2 are frequently elevated in human cancers and are associated with tumour aggressiveness and poor clinical outcome; however, whether and how B-type cyclins drive tumorigenesis is unknown. Here we show that cyclin B1 and B2 transgenic mice are highly prone to tumours, including tumour types where B-type cyclins serve as prognosticators. Cyclins B1 and B2 both induce aneuploidy when overexpressed but through distinct mechanisms, with cyclin B1 inhibiting separase activation, leading to anaphase bridges, and cyclin B2 triggering aurora-A-mediated Plk1 hyperactivation, resulting in accelerated centrosome separation and lagging chromosomes. Complementary experiments revealed that cyclin B2 and p53 act antagonistically to control aurora-A-mediated centrosome splitting and accurate chromosome segregation in normal cells. These data demonstrate a causative link between B-type cyclin overexpression and tumour pathophysiology, and uncover previously unknown functions of cyclin B2 and p53 in centrosome separation that may be perturbed in many human cancers.
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Affiliation(s)
- Hyun-Ja Nam
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | - Jan M. van Deursen
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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10
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Nam HJ, Lee IJ, Jang S, Bae CD, Kwak SJ, Lee JH. p90 ribosomal S6 kinase 1 (RSK1) isoenzyme specifically regulates cytokinesis progression. Cell Signal 2014; 26:208-19. [DOI: 10.1016/j.cellsig.2013.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 11/08/2013] [Accepted: 11/14/2013] [Indexed: 10/26/2022]
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Kim YS, Nam HJ, Chung HY, Kim ND, Ryu JH, Lee WJ, Arking R, Yoo MA. Role of xanthine dehydrogenase and aging on the innate immune response of Drosophila. J Am Aging Assoc 2013; 24:187-93. [PMID: 23604884 DOI: 10.1007/s11357-001-0020-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It has been proposed that uric acid is an important scavenger of deleterious oxygen species and peroxynitrite in biological systems. The cellular sources responsible for the generation of damage-causing reactive oxygen species (ROS) are widespread. Xanthine dehydrogenase (XDH) / oxidase (XOD) catalyzes the oxidation of xanthine to uric acid. The rosy (ry) gene encodes XDH/XOD in Drosophila melanogaster. XDH codes for uric acid which is a ROS scavenger. XOD however is an enzyme system implicated in ROS production. In this study, we investigated the roles of XDH in the fly's immune defense response to infection and in the aging process. We first compared ROS generation and nitric oxide (NO) level in the whole body and the gut of XDH mutant with those of wild type. Our results suggested that XDH has a protective effect with respect to both ROS and NO generations, particularly in the gut. We also examined the effect of a XDH deletion mutant on the relative sensitivity of the organism against bacterial infection, on the immune inducibility of antimicrobial peptides and on the effect of aging in the defensive response to infection. Our results strongly suggest that XDH plays an important role in the innate immune response and that the age-associated deterioration of the innate immune response might be, at least in part, associated with the loss of XDH activity in the aging process.
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Affiliation(s)
- Y S Kim
- Department of Molecular Biology, Pusan National University, Gumjung-ku, Pusan, 609-735 ; Institute of Genetic Engineering, Pusan National University, Gumjung-ku, Pusan, 609-735
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Kwak IH, Shin YH, Kim M, Cha HY, Nam HJ, Lee BS, Chaudhary SC, Pai KS, Lee JH. Epigallocatechin-3-gallate inhibits paracrine and autocrine hepatocyte growth factor/scatter factor-induced tumor cell migration and invasion. Exp Mol Med 2011; 43:111-20. [PMID: 21209554 DOI: 10.3858/emm.2011.43.2.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Aberrant activation of hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, Met, is involved in the development and progression of many human cancers. In the cell-based screening assay, (-)epigallocatechin-3-gallate (EGCG) inhibited HGF/SF-Met signaling as indicated by its inhibitory activity on HGF/SF-induced cell scattering and uPA activation (IC50=15.8 microgram/ml). Further analysis revealed that EGCG at low doses specifically inhibited HGF/SF-induced tyrosine phosphorylation of Met but not epidermal growth factor (EGF)-induced phosphorylation of EGF receptor (EGFR). On the other hand, high-dose EGCG decreased both Met and EGFR proteins. We also found that EGCG did not act on the intracellular portion of Met receptor tyrosine kinase, i.e., it inhibited InlB-dependent activation of Met but not NGF-induced activation of Trk-Met hybrid receptor. This inhibition decreased HGF-induced migration and invasion by parental or HGF/SF-transfected B16F10 melanoma cells in vitro in either a paracrine or autocrine manner. Furthermore, EGCG inhibited the invasion/metastasis of HGF/SF-transfected B16F10 melanoma cells in mice. Our data suggest the possible use of EGCG in human cancers associated with dysregulated paracrine or autocrine HGF/SF-Met signaling.
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Affiliation(s)
- In-hae Kwak
- Department of Biochemistry, Ajou University Medical School, Suwon, Korea
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Nam HJ, Park YY, Yoon G, Cho H, Lee JH. Co-treatment with hepatocyte growth factor and TGF-beta1 enhances migration of HaCaT cells through NADPH oxidase-dependent ROS generation. Exp Mol Med 2010; 42:270-9. [PMID: 20177149 DOI: 10.3858/emm.2010.42.4.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Wound healing requires re-epithelialization from the wound margin through keratinocyte proliferation and migration, and some growth factors are known to influence this process. In the present study, we found that the co-treatment with hepatocyte growth factor (HGF) and TGF-beta1 resulted in enhanced migration of HaCaT cells compared with either growth factor alone, and that N-acetylcysteine, an antioxidant agent, was the most effective among several inhibitors tested, suggesting the involvement of reactive oxygen species (ROS). Fluorescence-activated cell sorter analysis using 2,7-dichlorofluorescein diacetate (DCF-DA) dye showed an early (30 min) as well as a late (24 h) increase of ROS after scratch, and the increase was more prominent with the growth factor treatment. Diphenyliodonium (DPI), a potent inhibitor of NADPH oxidase, abolished the increase of ROS at 30 min, followed by the inhibition of migration, but not the late time event. More precisely, gene knockdown by shRNA for either Nox-1 or Nox-4 isozyme of gp91phox subunit of NADPH oxidase abolished both the early time ROS production and migration. However, HaCaT cell migration was not enhanced by treatment with H((2))O((2)). Collectively, co-treatment with HGF and TGF-beta1 enhances keratinocyte migration, accompanied with ROS generation through NADPH oxidase, involving Nox-1 and Nox-4 isozymes.
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Affiliation(s)
- Hyun-Ja Nam
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721, Korea
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14
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Abstract
The oncogenic ability of aberrant hepatocyte growth factor receptor (Met) signaling is thought to mainly rely on its mitogenic and anti-apoptotic effects. Recently, however, cumulating evidences suggest that genomic instability may be a crucial factor in tumorigenesis. Here, we address whether oncogenic Met receptor is linked to the centrosome abnormality and genomic instability. We showed that expression of the constitutive active Met (CA-Met) induced supernumerary centrosomes probably due to deregulated centrosome duplication, which was accompanied with multipolar spindle formation and aneuploidy. Interestingly, LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, significantly suppressed the appearance of supernumerary centrosomes. Moreover, knockdown of Akt with small interfering RNAs and overexpression of phosphatase and tensin homolog or dominant-negative Akt abrogated supernumerary centrosome formation, evidencing the involvement of PI3K signaling. We further showed that expression of CA-Met significantly increased aneuploidy in p53(-/-) HCT116 cells, but not in p53(+/+) HCT116 cells, indicating that the ability of CA-Met to induce chromosomal instability (CIN) phenotype is related with p53 status. Together, our data demonstrate that aberrant hepatocyte growth factor/Met signaling induces centrosome amplification and CIN via the PI3K-Akt pathway, providing an example that oncogenic growth factor signals prevalent in a wide variety of cancers have cross talks to centrosome abnormality and CIN.
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Affiliation(s)
- Hyun-Ja Nam
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Korea
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15
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Nam HJ, Kim S, Lee MW, Lee BS, Hara T, Saya H, Cho H, Lee JH. The ERK-RSK1 activation by growth factors at G2 phase delays cell cycle progression and reduces mitotic aberrations. Cell Signal 2008; 20:1349-58. [PMID: 18450423 DOI: 10.1016/j.cellsig.2008.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Revised: 03/08/2008] [Accepted: 03/08/2008] [Indexed: 12/23/2022]
Abstract
Growth factors accelerate G0 to S progression in the cell cycle, however, the roles of growth factors in other cell cycle phases are largely unknown. Here, we show that treatment of HeLa cells with hepatocyte growth factor (HGF) at G2 phase induced the G2/M transition delay as evidenced by FACS analysis as well as by mitotic index and time-lapse analyses. Growth factors such as epidermal growth factor (EGF) and fibroblast growth factor (FGF) also induced G2/M transition delay like HGF. HGF treatment at G2 phase causes a delayed activation of cyclin B1-associated kinase and a diminished nuclear translocation of cyclin B1. Either U0126, a MAPK kinase (MEK) inhibitor, or kinase-dead mutant of ribosomal S6 kinase (RSK) abolished the delay. Additionally, knockdown of RSK1, but not RSK2, with siRNA abrogated the delay, indicating that the extracellular-regulated protein kinase (ERK)-RSK1 mediates the HGF-induced delay. We further found that the delay in G2/M transition of cells expressing oncogenic HGF receptor, M1268T, was abolished by RSK1 knockdown. Intriguingly, we observed that HGF induced chromosomal segregation defects, and depletion of RSK1, but not RSK2, aggravated these chromosomal aberrations. Taken together, the ERK-RSK1 activation by growth factors delays G2/M transition and this might be required to maintain genomic integrity during growth factor stimulation.
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Affiliation(s)
- Hyun-Ja Nam
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, South Korea
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16
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Park YY, Nam HJ, Lee JH. Hepatocyte growth factor at S phase induces G2 delay through sustained ERK activation. Biochem Biophys Res Commun 2007; 356:300-5. [PMID: 17349975 DOI: 10.1016/j.bbrc.2007.02.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 02/23/2007] [Indexed: 11/23/2022]
Abstract
The effect of growth factors on the cell cycle progression, except G1/S transition, is poorly understood. Herein, we examined the effect of hepatocyte growth factor (HGF) treated at S phase on the cell cycle progression of HeLa cells. Interestingly, the treatment resulted in G2 delay, evidenced by flow cytometric and mitotic index analyses. The delay corresponded with the delay of degradation of cyclin A and cyclin B, and the delay of decrease of Cdk1/cyclin B and Cdk2/cyclin A kinase activities. As for the signaling responsible, sustained activation of ERK, but neither of p38MAPK nor of JNK, was observed after HGF treatment at S phase. Furthermore, U0126, an inhibitor of MEK1, and DN-MEK partially abrogated the G2 delay, indicating that activation of MEK-ERK pathway is involved. Taken together, HGF treatment of HeLa cells at S phase induces G2 delay partially through sustained activation of ERK signaling.
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Affiliation(s)
- Yun Yeon Park
- Department of Biochemistry, Ajou University School of Medicine, Suwon 443-721, Republic of Korea
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Kim IS, Kim ER, Nam HJ, Chin MO, Moon YH, Oh MR, Yeo UC, Song SM, Kim JS, Uhm MR, Beck NS, Jin DK. Activating mutation of GS alpha in McCune-Albright syndrome causes skin pigmentation by tyrosinase gene activation on affected melanocytes. Horm Res 2000; 52:235-40. [PMID: 10844413 DOI: 10.1159/000023467] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
McCune-Albright syndrome (MAS) is a sporadic disease characterized by café-au-lait spots, polyostotic fibrous dysplasia and hyperfunctional endocrinopathies. To elucidate the mechanism of skin pigmentation, melanocytes, keratinocytes and fibroblasts were primary cultured from the café-au-lait spot of a MAS patient. Then, mutational analysis and morphologic evaluation were performed. Also, cAMP level and tyrosinase gene expression in cultured cells were determined. Only Gsalpha mutation was found in affected melanocytes and the cAMP level in affected melanocytes was higher than that of normal melanocytes. The mRNA expression of tyrosinase gene was increased in the affected melanocytes. This study suggests that skin pigmentation of MAS results from activating mutation of Gsalpha in melanocytes and the mechanism involves the c-AMP-mediated tyrosinase gene activation.
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Affiliation(s)
- I S Kim
- Department of Pediatrics, SungAe General Hospital, SungAe Life Science Research Institute, Seoul, Korea
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Kim IS, Kim DH, Han SM, Chin MU, Nam HJ, Cho HP, Choi SY, Song BJ, Kim ER, Bae YS, Moon YH. Truncated form of importin alpha identified in breast cancer cell inhibits nuclear import of p53. J Biol Chem 2000; 275:23139-45. [PMID: 10930427 DOI: 10.1074/jbc.m909256199] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Disruption of the function of tumor suppressor proteins occasionally can be dependent on their subcellular localization. In about 40% of the breast cancer tissues, p53 is found in the cytoplasm as opposed to the nucleus, where it resides in normal breast cells. This means that the regulation of subcellular location of p53 is an important mechanism in controlling its function. The transport factors required for the nuclear export of p53 and the mechanisms of their nuclear export have been extensively characterized. However, little is known about the mechanism of nuclear import of p53. p53 contains putative nuclear localization signals (NLSs) which would interact with a nuclear transport factor, importin alpha. In this report we demonstrate that importin alpha binds to NLSI in p53 and mediates the nuclear import of p53. Reverse transcriptase-polymerase chain reaction and sequencing analyses showed that a truncated importin alpha deleted the region encoding the putative NLS-binding domain of p53, suggesting that it could not bind to NLSs of p53 proteins. Binding of importin alpha to p53 was confirmed by using yeast two-hybrid assay. When expressed in CHO-K1 cells, the truncated importin alpha predominantly localized to the cytoplasm. In truncated importin alpha expressing cells, p53 preferentially localized to cytoplasmic sites as well. A significant increase in the p21(waf1/cip1) mRNA level and induction of apoptosis were also observed in importin alpha overexpressing cells. These results strongly suggest that importin alpha functions as a component of the NLS receptor for p53 and mediates nuclear import of p53.
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Affiliation(s)
- I S Kim
- Sung Ae Life Science Research Institute, Kyeonggi 423-030, South Korea
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Kim HJ, Na HS, Sung B, Nam HJ, Chung YJ, Hong SK. Is sympathetic sprouting in the dorsal root ganglia responsible for the production of neuropathic pain in a rat model? Neurosci Lett 1999; 269:103-6. [PMID: 10430515 DOI: 10.1016/s0304-3940(99)00435-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Partial peripheral nerve injury often results in neuropathic pain that is aggravated by sympathetic excitation and induces sympathetic nerve sprouting in both the injured nerve and corresponding dorsal root ganglia (DRGs). Presently, the functional mechanisms of the interactions between the sprouting and injured somatic afferents remain uncertain. This study was performed to see whether the sprouting in the DRGs plays a key role in the development of neuropathic pain. To this aim, we compared two groups of rats, both of which were subjected to unilateral transection of the superior and inferior caudal trunks at the level between the S1 and S2 spinal nerves, with respect to sympathetic fiber sprouting; one group showed well-developed neuropathic pain behaviors (i.e. mechanical, cold and warm allodynia signs) and the other group showed poorly-developed ones. Immuno-histochemical staining with tyrosine hydroxylase (TH) antibody of the injured S1 DRG taken from both groups of rats after behavioral tests revealed that the magnitude of penetration of TH-positive fibers into the S1 DRG was not significantly different between the two groups. These results suggest that sympathetic nerve sprouting in the injured DRG is not a key factor in the development of neuropathic pain.
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Affiliation(s)
- H J Kim
- Neuroscience Research Institute, Korea University College of Medicine, Seoul, South Korea
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20
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Abstract
Most receptor-like protein tyrosine phosphatases (RPTPs) contain two conserved phosphatase domains (D1 and D2) in their intracellular region. The carboxy-terminal D2 domain has little or no catalytic activity. The crystal structure of the tandem D1 and D2 domains of the human RPTP LAR revealed that the tertiary structures of the LAR D1 and D2 domains are very similar to each other, with the exception of conformational differences at two amino acid positions in the D2 domain. Site-directed mutational changes at these positions (Leu-1644-to-Tyr and Glu-1779-to-Asp) conferred a robust PTPase activity to the D2 domain. The catalytic sites of both domains are accessible, in contrast to the dimeric blocked orientation model previously suggested. The relative orientation of the LAR D1 and D2 domains, constrained by a short linker, is stabilized by extensive interdomain interactions, suggesting that this orientation might be favored in solution.
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Affiliation(s)
- H J Nam
- Dana-Farber Cancer Institute and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Kim YI, Na HS, Kim SH, Han HC, Yoon YW, Sung B, Nam HJ, Shin SL, Hong SK. Cell type-specific changes of the membrane properties of peripherally-axotomized dorsal root ganglion neurons in a rat model of neuropathic pain. Neuroscience 1998; 86:301-9. [PMID: 9692763 DOI: 10.1016/s0306-4522(98)00022-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent evidence indicates that neuropathic pain from partial peripheral nerve injury is maintained by electrophysiologically abnormal signals from injured sensory neurons. To gain an insight into the mechanisms underlying this electrophysiological abnormality, we examined the effects of S1 spinal nerve transection on the membrane properties of S1 dorsal root ganglion neurons one to two weeks after injury. This injury produced significant action potential broadening [40% (1 ms) in C-, 149% (1.5 ms) in A delta- and 84% (0.5 ms) in A alpha/beta-cells], which was primarily due to the enhancement of the "shoulder" appearing on the falling phase of the action potential in C- and A delta-cells and the emergence of a shoulder in A alpha/beta-cells, and significant cell-type specific changes in the time-course of the rising phase of the action potential; i.e. an increase in rise time (A delta: 35%, 0.15 ms; A alpha/beta: 13%, 0.04 ms) and a decrease in the maximal rate of rise (A delta: 17%, 77 V/s; A alpha/beta: 13%, 79 V/s). In addition, the nerve injury led to a significant reduction of the rheobase, an index of neuronal excitability, in all types of cells (by 41% in C-, 71% in A delta- and 59% in A alpha/beta-cells). The reduction of rheobase in A-cells was associated with a concomitant increase in apparent input resistance (by 269% in A delta- and 192% in A alpha/beta-cells), which was measured near the resting membrane potential. By contrast, the rheobase reduction in C-cells was associated with a concurrent depolarizing shift (approximately 4 mV) of the resting membrane potential. The nerve injury-induced reduction of rheobase was not accompanied by related change in input resistance or threshold potential in any of the cell populations. The present results indicate that chronic peripheral axotomy of dorsal root ganglion neurons, which gives rise to neuropathic pain, produces profound changes in the action potential waveform of dorsal root ganglion neurons in a cell type-specific fashion. Furthermore, the results suggest that the axotomy increases the excitability of dorsal root ganglion neurons not by altering input resistance (i.e. leak conductance) or threshold potential, but by increasing apparent input resistance near the resting membrane potential in A-cells and decreasing the resting membrane potential in C-cells.
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Affiliation(s)
- Y I Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul, South Korea
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22
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Abstract
BACKGROUND The Abl nonreceptor tyrosine kinase is implicated in a range of cellular processes and its transforming variants are involved in human leukemias. The N-terminal regulatory region of the Abl protein contains Src homology domains SH2 and SH3 which have been shown to be important for the regulation of its activity in vivo. These domains are often found together in the same protein and biochemical data suggest that the functions of one domain can be influenced by the other. RESULTS We have determined the crystal structure of the Abl regulatory region containing the SH3 and SH2 domains. In general, the individual domains are very similar to those of previously solved structures, although the Abl SH2 domain contains a loop which is extended so that one side of the resulting phosphotyrosine-binding pocket is open. In our structure the protein exists as a monomer with no intermolecular contacts to which a biological function may be attributed. However, there is a significant intramolecular contact between a loop of the SH3 domain and the extended loop of the SH2 domain. This contact surface includes the SH2 loop segment that is responsible for binding the phosphate moiety of phosphotyrosine-containing proteins and is therefore critical for orienting peptide interactions. CONCLUSIONS The crystal structure of the composite Abl SH3-SH2 domain provides the first indication of how SH2 and SH3 domains communicate with each other within the same molecule and why the presence of one directly influences the activity of the other. This is the first clear evidence that these two domains are in contact with each other. The results suggest that this direct interaction between the two domains may affect the ligand binding properties of the SH2 domain, thus providing an explanation for biochemical and functional data concerning the Bcr-Abl kinase.
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Affiliation(s)
- H J Nam
- Department of X-ray Crystallography, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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Kim HJ, Na HS, Nam HJ, Park KA, Hong SK, Kang BS. Sprouting of sympathetic nerve fibers into the dorsal root ganglion following peripheral nerve injury depends on the injury site. Neurosci Lett 1996; 212:191-4. [PMID: 8843105 DOI: 10.1016/0304-3940(96)12811-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Peripheral nerve injury often induces sympathetic nerve fiber sprouting in the dorsal root ganglion (DRG) and injured nerve. Presently, the underlying mechanism and functional significance of the sprouting are unknown. This study was performed to see whether the degree of the sprouting in the DRG was a function of the distance between the DRG and injury site. To this aim, we compared two groups of rats with respect to the sympathetic nerve fibers sprouting in the S1-3 DRG; one group was subjected to unilateral inferior and superior caudal trunk transections at the level between the S3 and S4 spinal nerves (S34 group) and the other group at the levels between the S1 and S2, between S2 and S3 and between S3 and S4 spinal nerves (S123 group). The transections in both groups equally eliminated the inputs from the tail to the S1-3 DRG, but the distance from the S1/S2 DRG to the injury site was different between the two groups. Immunohistochemical staining with tyrosine hydroxylase (TH) antibody of the S1-3 DRG removed from rats a week after the injury revealed that the degree of penetration of TH-positive fibers into the S1 and S2 DRG was much more extensive in the S123 group than in the S34 group, whereas that into the S3 DRG was not significantly different between the two groups. These results suggest that the extent of the sympathetic nerve fiber sprouting in the DRG following peripheral nerve injury is inversely related to the distance between the DRG and injury site.
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Affiliation(s)
- H J Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, South Korea
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