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Wei M, Zhang N, Li XD. Characterisation of the myosin light chain kinase (MLCK) gene of Locusta migratoria and the encoded MLCK. INSECT MOLECULAR BIOLOGY 2024; 33:338-349. [PMID: 38411321 DOI: 10.1111/imb.12902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Accepted: 02/14/2024] [Indexed: 02/28/2024]
Abstract
Myosin light chain kinase (MLCK) is a dedicated kinase of myosin regulatory light chain (RLC), playing an essential role in the regulation of muscle contraction and cell motility. Much of the knowledge about MLCK comes from the study of vertebrate MLCK, and little is known about insect MLCK. Here, we identified the single MLCK gene in the locust Locusta migratoria, which spans over 1400 kb, includes 62 exons and accounts for at least five transcripts. We found that the five distinct transcripts of the locust MLCK gene are expressed in a tissue-specific manner, including three muscle-specific isoforms and two generic isoforms. To characterise the kinase activity of locust MLCK, we recombinantly expressed LmMLCK-G, the smallest locust MLCK isoform, in insect Sf9 cells. We demonstrated that LmMLCK-G is a Ca2+/calmodulin-dependent kinase that specifically phosphorylates serine 50 of locust muscle myosin RLC (LmRLC). Additionally, we found that almost all LmRLC molecules in the flight muscle and the hindleg muscles of adult locusts are phosphorylated.
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Affiliation(s)
- Miao Wei
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ning Zhang
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xiang-Dong Li
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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2
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Baliova M, Jursky F. Manganese- and zinc-coordinated interaction of Schistosoma japonicum glutathione S-transferase with neurotransmitter transporters GlyT1 and GAT3 in vitro. Exp Parasitol 2024; 259:108721. [PMID: 38369179 DOI: 10.1016/j.exppara.2024.108721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
Glutathione S-transferases (GSTs) are a family of multifunctional isoenzymes involved in the neutralization of toxic compounds, drug resistance and several other cellular functions. The glutathione S-transferase enzyme of Schistosoma japonicum (SjGST-26) plays a role in human schistosomiasis and is also a frequently used fusion partner in mammalian and bacterial expression and pull-down systems. GSTs seem not to be naturally associated with metal ions. Exceptionally, in vitro, metal binding sites have been previously described in some schistosome GSTs; however, their possible physiological role is unclear. Molecules of several neurotransmitter transporters also contain a regulatory zinc binding site, which affects their transport cycle. Here we show that among several metals, manganese and zinc are able to induce a specific protein interaction of SjGST-26 with the glycine transporter GlyT1 and the GABA transporter GAT3 in vitro. The results suggest that metal-binding sites on SjGST-26 and neurotransmitter transporters might function in metal-coordinated interactions with other metalloproteins. Our results additionally indicate that the presence of metal ions in SjGST-26-based GST protein pull-down assays may lead to a false-positive interaction if the potential interacting target is the metalloprotein.
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Affiliation(s)
- Martina Baliova
- Laboratory of Neurobiology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska Cesta 21, 845 51, Bratislava, Slovakia
| | - Frantisek Jursky
- Laboratory of Neurobiology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska Cesta 21, 845 51, Bratislava, Slovakia.
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3
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EswarKumar N, Yang CH, Tewary S, Peng WH, Chen GC, Yeh YQ, Yang HC, Ho MC. An integrative approach unveils a distal encounter site for rPTPε and phospho-Src complex formation. Structure 2023; 31:1567-1577.e5. [PMID: 37794594 DOI: 10.1016/j.str.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/10/2023] [Accepted: 09/07/2023] [Indexed: 10/06/2023]
Abstract
The structure determination of protein tyrosine phosphatase (PTP): phospho-protein complexes, which is essential to understand how specificity is achieved at the amino acid level, remains a significant challenge for protein crystallography and cryoEM due to the transient nature of binding interactions. Using rPTPεD1 and phospho-SrcKD as a model system, we have established an integrative workflow to address this problem, by means of which we generate a protein:phospho-protein complex model using predetermined protein structures, SAXS and pTyr-tailored MD simulations. Our model reveals transient protein-protein interactions between rPTPεD1 and phospho-SrcKD and is supported by three independent experimental validations. Measurements of the association rate between rPTPεD1 and phospho-SrcKD showed that mutations on the rPTPεD1: SrcKD complex interface disrupts these transient interactions, resulting in a reduction in protein-protein association rate and, eventually, phosphatase activity. This integrative approach is applicable to other PTP: phospho-protein complexes and the characterization of transient protein-protein interface interactions.
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Affiliation(s)
- Nadendla EswarKumar
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan; Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Cheng-Han Yang
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan; Department of Chemistry, Fu Jen Catholic University, New Taipei City 24205, Taiwan
| | - Sunilkumar Tewary
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan
| | - Wen-Hsin Peng
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan
| | - Guang-Chao Chen
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan
| | - Yi-Qi Yeh
- National Synchrotron Radiation Research Center, Hsin-Chu 300, Taiwan
| | - Hsiao-Ching Yang
- Department of Chemistry, Fu Jen Catholic University, New Taipei City 24205, Taiwan.
| | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan.
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4
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Ercan H, Resch U, Hsu F, Mitulovic G, Bileck A, Gerner C, Yang JW, Geiger M, Miller I, Zellner M. A Practical and Analytical Comparative Study of Gel-Based Top-Down and Gel-Free Bottom-Up Proteomics Including Unbiased Proteoform Detection. Cells 2023; 12:747. [PMID: 36899884 PMCID: PMC10000902 DOI: 10.3390/cells12050747] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Proteomics is an indispensable analytical technique to study the dynamic functioning of biological systems via different proteins and their proteoforms. In recent years, bottom-up shotgun has become more popular than gel-based top-down proteomics. The current study examined the qualitative and quantitative performance of these two fundamentally different methodologies by the parallel measurement of six technical and three biological replicates of the human prostate carcinoma cell line DU145 using its two most common standard techniques, label-free shotgun and two-dimensional differential gel electrophoresis (2D-DIGE). The analytical strengths and limitations were explored, finally focusing on the unbiased detection of proteoforms, exemplified by discovering a prostate cancer-related cleavage product of pyruvate kinase M2. Label-free shotgun proteomics quickly yields an annotated proteome but with reduced robustness, as determined by three times higher technical variation compared to 2D-DIGE. At a glance, only 2D-DIGE top-down analysis provided valuable, direct stoichiometric qualitative and quantitative information from proteins to their proteoforms, even with unexpected post-translational modifications, such as proteolytic cleavage and phosphorylation. However, the 2D-DIGE technology required almost 20 times as much time per protein/proteoform characterization with more manual work. Ultimately, this work should expose both techniques' orthogonality with their different contents of data output to elucidate biological questions.
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Affiliation(s)
- Huriye Ercan
- Centre for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
- Immunology Outpatient Clinic, 1090 Vienna, Austria
| | - Ulrike Resch
- Centre for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Felicia Hsu
- Centre for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Goran Mitulovic
- Proteomics Core Facility, Clinical Department of Laboratory Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Andrea Bileck
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
- Joint Metabolome Facility, University of Vienna and Medical University of Vienna, 1090 Vienna, Austria
| | - Christopher Gerner
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
- Joint Metabolome Facility, University of Vienna and Medical University of Vienna, 1090 Vienna, Austria
| | - Jae-Won Yang
- Centre for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Margarethe Geiger
- Centre for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Ingrid Miller
- Institute of Medical Biochemistry, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Maria Zellner
- Centre for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
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5
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Kong Y, Chen J, Jiang L, Chen H, Shen Y, Wang L, Yan Y, Zhou H, Zheng H, Yu F, Ming Z. Structural and biochemical basis of Arabidopsis FERONIA receptor kinase-mediated early signaling initiation. PLANT COMMUNICATIONS 2023:100559. [PMID: 36774537 PMCID: PMC10363478 DOI: 10.1016/j.xplc.2023.100559] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/11/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Accumulating evidence indicates that early and essential events for receptor-like kinase (RLK) function involve both autophosphorylation and substrate phosphorylation. However, the structural and biochemical basis for these events is largely unclear. Here, we used RLK FERONIA (FER) as a model and crystallized its core kinase domain (FER-KD) and two FER-KD mutants (K565R, S525A) in complexes with ATP/ADP and Mg2+ in the unphosphorylated state. Unphosphorylated FER-KD was found to adopt an unexpected active conformation in its crystal structure. Moreover, unphosphorylated FER-KD mutants with reduced (S525A) or no catalytic activity (K565R) also adopt similar active conformations. Biochemical studies revealed that FER-KD is a dual-specificity kinase, and its autophosphorylation is accomplished via an intermolecular mechanism. Further investigations confirmed that initiating substrate phosphorylation requires autophosphorylation of the activation segment on T696, S701, and Y704. This study reveals the structural and biochemical basis for the activation and regulatory mechanism of FER, providing a paradigm for the early steps in RLK signaling initiation.
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Affiliation(s)
- Yanqiong Kong
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning 530004, P.R. China
| | - Jia Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China
| | - Lingli Jiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China
| | - Hong Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China
| | - Yanan Shen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China
| | - Lifeng Wang
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, P.R. China
| | - Yujie Yan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China
| | - Huan Zhou
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, P.R. China
| | - Heping Zheng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China
| | - Feng Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, P.R. China; State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, P.R. China.
| | - Zhenhua Ming
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning 530004, P.R. China.
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6
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Huang Y, Rafael Guimarães T, Todd N, Ferguson C, Weiss KM, Stauffer FR, McDermott B, Hurtle BT, Saito T, Saido TC, MacDonald ML, Homanics GE, Thathiah A. G protein-biased GPR3 signaling ameliorates amyloid pathology in a preclinical Alzheimer's disease mouse model. Proc Natl Acad Sci U S A 2022; 119:e2204828119. [PMID: 36161942 PMCID: PMC9546571 DOI: 10.1073/pnas.2204828119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/01/2022] [Indexed: 11/24/2022] Open
Abstract
Biased G protein-coupled receptor (GPCR) ligands, which preferentially activate G protein or β-arrestin signaling pathways, are leading to the development of drugs with superior efficacy and reduced side effects in heart disease, pain management, and neuropsychiatric disorders. Although GPCRs are implicated in the pathophysiology of Alzheimer's disease (AD), biased GPCR signaling is a largely unexplored area of investigation in AD. Our previous work demonstrated that GPR3-mediated β-arrestin signaling modulates amyloid-β (Aβ) generation in vitro and that Gpr3 deficiency ameliorates Aβ pathology in vivo. However, Gpr3-deficient mice display several adverse phenotypes, including elevated anxiety-like behavior, reduced fertility, and memory impairment, which are potentially associated with impaired G protein signaling. Here, we generated a G protein-biased GPR3 mouse model to investigate the physiological and pathophysiological consequences of selective elimination of GPR3-mediated β-arrestin signaling in vivo. In contrast to Gpr3-deficient mice, G protein-biased GPR3 mice do not display elevated anxiety levels, reduced fertility, or cognitive impairment. We further determined that G protein-biased signaling reduces soluble Aβ levels and leads to a decrease in the area and compaction of amyloid plaques in the preclinical AppNL-G-F AD mouse model. The changes in amyloid pathology are accompanied by robust microglial and astrocytic hypertrophy, which suggest a protective glial response that may limit amyloid plaque development in G protein-biased GPR3 AD mice. Collectively, these studies indicate that GPR3-mediated G protein and β-arrestin signaling produce discrete and separable effects and provide proof of concept for the development of safer GPCR-targeting therapeutics with more directed pharmacological action for AD.
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Affiliation(s)
- Yunhong Huang
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
| | - Thais Rafael Guimarães
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA,15260
| | - Nicholas Todd
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
- Graduate Program in Molecular Pharmacology, University of Pittsburgh, Pittsburgh, PA, 15260
| | - Carolyn Ferguson
- Department of Anesthesiology & Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, 15260
| | - Kathryn M. Weiss
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
| | - Fiona R. Stauffer
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
| | - Breanne McDermott
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
| | - Bryan T. Hurtle
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA,15260
| | - Takashi Saito
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Science, Nagoya, 467-8601, Japan
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, 351-0198, Japan
| | - Takaomi C. Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, 351-0198, Japan
| | - Matthew L. MacDonald
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15260
- Biomedical Mass Spectrometry Center, University of Pittsburgh, Pittsburgh, PA,15260
| | - Gregg E. Homanics
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
- Department of Anesthesiology & Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, 15260
- University of Pittsburgh Brain Institute, University of Pittsburgh, Pittsburgh, PA, 15260
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15260
| | - Amantha Thathiah
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA,15260
- University of Pittsburgh Brain Institute, University of Pittsburgh, Pittsburgh, PA, 15260
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, 15260
- Center for Protein Conformational Diseases, Kenneth P. Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA,15260
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mTORC1 controls Golgi architecture and vesicle secretion by phosphorylation of SCYL1. Nat Commun 2022; 13:4685. [PMID: 35948564 PMCID: PMC9365812 DOI: 10.1038/s41467-022-32487-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/30/2022] [Indexed: 12/04/2022] Open
Abstract
The protein kinase mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth and proliferation, supporting anabolic reactions and inhibiting catabolic pathways like autophagy. Its hyperactivation is a frequent event in cancer promoting tumor cell proliferation. Several intracellular membrane-associated mTORC1 pools have been identified, linking its function to distinct subcellular localizations. Here, we characterize the N-terminal kinase-like protein SCYL1 as a Golgi-localized target through which mTORC1 controls organelle distribution and extracellular vesicle secretion in breast cancer cells. Under growth conditions, SCYL1 is phosphorylated by mTORC1 on Ser754, supporting Golgi localization. Upon mTORC1 inhibition, Ser754 dephosphorylation leads to SCYL1 displacement to endosomes. Peripheral, dephosphorylated SCYL1 causes Golgi enlargement, redistribution of early and late endosomes and increased extracellular vesicle release. Thus, the mTORC1-controlled phosphorylation status of SCYL1 is an important determinant regulating subcellular distribution and function of endolysosomal compartments. It may also explain the pathophysiology underlying human genetic diseases such as CALFAN syndrome, which is caused by loss-of-function of SCYL1. mTORC1 is a master regulator of cell growth with well-known functions in inhibiting autophagic vesicle formation. Here, the authors show that mTORC1 also affects Golgi architecture and vesicle secretion by phosphorylating the scaffold protein SCYL1.
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8
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Artim SC, Kiyatkin A, Lemmon MA. Comparison of tyrosine kinase domain properties for the neurotrophin receptors TrkA and TrkB. Biochem J 2020; 477:4053-4070. [PMID: 33043964 PMCID: PMC7606831 DOI: 10.1042/bcj20200695] [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: 08/27/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 11/17/2022]
Abstract
The tropomyosin-related kinase (Trk) family consists of three receptor tyrosine kinases (RTKs) called TrkA, TrkB, and TrkC. These RTKs are regulated by the neurotrophins, a class of secreted growth factors responsible for the development and function of neurons. The Trks share a high degree of homology and utilize overlapping signaling pathways, yet their signaling is associated with starkly different outcomes in certain cancers. For example, in neuroblastoma, TrkA expression and signaling correlates with a favorable prognosis, whereas TrkB is associated with poor prognoses. To begin to understand how activation of the different Trks can lead to such distinct cellular outcomes, we investigated differences in kinase activity and duration of autophosphorylation for the TrkA and TrkB tyrosine kinase domains (TKDs). We find that the TrkA TKD has a catalytic efficiency that is ∼2-fold higher than that of TrkB, and becomes autophosphorylated in vitro more rapidly than the TrkB TKD. Studies with mutated TKD variants suggest that a crystallographic dimer seen in many TrkA (but not TrkB) TKD crystal structures, which involves the kinase-insert domain, may contribute to this enhanced TrkA autophosphorylation. Consistent with previous studies showing that cellular context determines whether TrkB signaling is sustained (promoting differentiation) or transient (promoting proliferation), we also find that TrkB signaling can be made more transient in PC12 cells by suppressing levels of p75NTR. Our findings shed new light on potential differences between TrkA and TrkB signaling, and suggest that subtle differences in signaling dynamics can lead to substantial shifts in the cellular outcome.
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Affiliation(s)
- Stephen C. Artim
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Present address: Merck Research Laboratories, Merck, South San Francisco, CA 94080, USA
| | - Anatoly Kiyatkin
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Department of Pharmacology and Cancer Biology Institute, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Mark A. Lemmon
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Department of Pharmacology and Cancer Biology Institute, Yale University School of Medicine, New Haven, CT, 06520, USA
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9
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Structural Basis for the Activation and Target Site Specificity of CDC7 Kinase. Structure 2020; 28:954-962.e4. [PMID: 32521228 PMCID: PMC7416108 DOI: 10.1016/j.str.2020.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/11/2020] [Accepted: 05/19/2020] [Indexed: 12/13/2022]
Abstract
CDC7 is an essential Ser/Thr kinase that acts upon the replicative helicase throughout the S phase of the cell cycle and is activated by DBF4. Here, we present crystal structures of a highly active human CDC7-DBF4 construct. The structures reveal a zinc-finger domain at the end of the kinase insert 2 that pins the CDC7 activation loop to motif M of DBF4 and the C lobe of CDC7. These interactions lead to ordering of the substrate-binding platform and full opening of the kinase active site. In a co-crystal structure with a mimic of MCM2 Ser40 phosphorylation target, the invariant CDC7 residues Arg373 and Arg380 engage phospho-Ser41 at substrate P+1 position, explaining the selectivity of the S-phase kinase for Ser/Thr residues followed by a pre-phosphorylated or an acidic residue. Our results clarify the role of DBF4 in activation of CDC7 and elucidate the structural basis for recognition of its preferred substrates. DBF4 activates CDC7 kinase via a two-step mechanism Zinc-finger domain in CDC7 KI2 interacts with DBF4 motif M Invariant CDC7 residues Arg373 and Arg380 engage P+1 substrate site
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10
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Baretić D, Jenkyn-Bedford M, Aria V, Cannone G, Skehel M, Yeeles JTP. Cryo-EM Structure of the Fork Protection Complex Bound to CMG at a Replication Fork. Mol Cell 2020; 78:926-940.e13. [PMID: 32369734 PMCID: PMC7276988 DOI: 10.1016/j.molcel.2020.04.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 12/15/2022]
Abstract
The eukaryotic replisome, organized around the Cdc45-MCM-GINS (CMG) helicase, orchestrates chromosome replication. Multiple factors associate directly with CMG, including Ctf4 and the heterotrimeric fork protection complex (Csm3/Tof1 and Mrc1), which has important roles including aiding normal replication rates and stabilizing stalled forks. How these proteins interface with CMG to execute these functions is poorly understood. Here we present 3 to 3.5 Å resolution electron cryomicroscopy (cryo-EM) structures comprising CMG, Ctf4, and the fork protection complex at a replication fork. The structures provide high-resolution views of CMG-DNA interactions, revealing a mechanism for strand separation, and show Csm3/Tof1 “grip” duplex DNA ahead of CMG via a network of interactions important for efficient replication fork pausing. Although Mrc1 was not resolved in our structures, we determine its topology in the replisome by cross-linking mass spectrometry. Collectively, our work reveals how four highly conserved replisome components collaborate with CMG to facilitate replisome progression and maintain genome stability. Cryo-EM structure of Csm3/Tof1 and Ctf4 bound to the eukaryotic CMG helicase Csm3/Tof1 are positioned at the front of the replisome where they grip duplex DNA High-resolution views of CMG-DNA contacts suggest a mechanism for strand separation Mrc1 binds across one side of CMG contacting the front and back of the replisome
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Affiliation(s)
- Domagoj Baretić
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | | | - Valentina Aria
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Giuseppe Cannone
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Mark Skehel
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Joseph T P Yeeles
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK.
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11
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Bhattacharyya M, Lee YK, Muratcioglu S, Qiu B, Nyayapati P, Schulman H, Groves JT, Kuriyan J. Flexible linkers in CaMKII control the balance between activating and inhibitory autophosphorylation. eLife 2020; 9:e53670. [PMID: 32149607 PMCID: PMC7141811 DOI: 10.7554/elife.53670] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/06/2020] [Indexed: 12/24/2022] Open
Abstract
The many variants of human Ca2+/calmodulin-dependent protein kinase II (CaMKII) differ in the lengths and sequences of disordered linkers connecting the kinase domains to the oligomeric hubs of the holoenzyme. CaMKII activity depends on the balance between activating and inhibitory autophosphorylation (on Thr 286 and Thr 305/306, respectively, in the human α isoform). Variation in the linkers could alter transphosphorylation rates within a holoenzyme and the balance of autophosphorylation outcomes. We show, using mammalian cell expression and a single-molecule assay, that the balance of autophosphorylation is flipped between CaMKII variants with longer and shorter linkers. For the principal isoforms in the brain, CaMKII-α, with a ~30 residue linker, readily acquires activating autophosphorylation, while CaMKII-β, with a ~200 residue linker, is biased towards inhibitory autophosphorylation. Our results show how the responsiveness of CaMKII holoenzymes to calcium signals can be tuned by varying the relative levels of isoforms with long and short linkers.
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Affiliation(s)
- Moitrayee Bhattacharyya
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Young Kwang Lee
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - Serena Muratcioglu
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Baiyu Qiu
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Priya Nyayapati
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Howard Schulman
- Panorama Institute of Molecular MedicineSunnyvaleUnited States
| | - Jay T Groves
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, BerkeleyBerkeleyUnited States
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, BerkeleyBerkeleyUnited States
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12
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Zhou Y, Millott R, Kim HJ, Peng S, Edwards RA, Skene-Arnold T, Hammel M, Lees-Miller SP, Tainer JA, Holmes CFB, Glover JNM. Flexible Tethering of ASPP Proteins Facilitates PP-1c Catalysis. Structure 2019; 27:1485-1496.e4. [PMID: 31402222 DOI: 10.1016/j.str.2019.07.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/14/2019] [Accepted: 07/22/2019] [Indexed: 12/15/2022]
Abstract
ASPP (apoptosis-stimulating proteins of p53) proteins bind PP-1c (protein phosphatase 1) and regulate p53 impacting cancer cell growth and apoptosis. Here we determine the crystal structure of the oncogenic ASPP protein, iASPP, bound to PP-1c. The structure reveals a 1:1 complex that relies on interactions of the iASPP SILK and RVxF motifs with PP-1c, plus interactions of the PP-1c PxxPxR motif with the iASPP SH3 domain. Small-angle X-ray scattering analyses suggest that the crystal structure undergoes slow interconversion with more extended conformations in solution. We show that iASPP, and the tumor suppressor ASPP2, enhance the catalytic activity of PP-1c against the small-molecule substrate, pNPP as well as p53. The combined results suggest that PxxPxR binding to iASPP SH3 domain is critical for complex formation, and that the modular ASPP-PP-1c interface provides dynamic flexibility that enables functional binding and dephosphorylation of p53 and other diverse protein substrates.
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Affiliation(s)
- Yeyun Zhou
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Robyn Millott
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Hyeong Jin Kim
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Shiyun Peng
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Ross A Edwards
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Tamara Skene-Arnold
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Michal Hammel
- Molecular Biophysics & Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada
| | - John A Tainer
- Molecular Biophysics & Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Charles F B Holmes
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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13
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Gu SH, Lin PL, Hsieh HY. Bombyxin/Akt signaling in relation to the embryonic diapause process of the silkworm, Bombyx mori. JOURNAL OF INSECT PHYSIOLOGY 2019; 116:32-40. [PMID: 31022386 DOI: 10.1016/j.jinsphys.2019.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 04/17/2019] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
Our previous study showed that phosphorylation of glycogen synthase kinase (GSK)-3β is related to the embryonic diapause process in Bombyx. However, the upstream signaling pathway was not clearly understood. In the present study, we examined bombyxin/Akt signaling in relation to the embryonic diapause process of B. mori. Results showed that GSK-3β phosphorylation stimulated by dechorionation was blocked by LY294002, a specific phosphatidylinositol 3-kinase (PI3K) inhibitor, indicating involvement of PI3K in GSK-3β phosphorylation in dechorionated eggs. Direct determination of Akt phosphorylation showed that dechorionation stimulated Akt phosphorylation. The Akt phosphorylation was blocked by LY294002. Temporal changes in Akt phosphorylation showed that different changing patterns exist between diapause and developing eggs. Relatively higher phosphorylation levels of Akt were detected between days 3 and 5 after oviposition in non-diapause eggs compared to those at the same stages in diapause eggs. Upon treatment with HCl, which prevents diapause initiation, Akt phosphorylation levels exhibited a later and much broader peak compared to diapause eggs. Examination of expression levels of the bombyxin-Z1 gene showed that in diapause eggs, a major peak occurred 1 day after oviposition, and its level then sharply decreased on day 2. However, in both non-diapause and HCl-treated eggs, a major broad peak was detected between days 1 and 4 after oviposition. These temporal changes in bombyxin-Z1 gene expression levels during embryonic stages coincided with changes in Akt phosphorylation, indicating that bombyxin-Z1 is likely an upstream signaling component for Akt phosphorylation. Taken together, our results indicated that PI3K/Akt is an upstream signaling pathway for GSK-3β phosphorylation and is associated with the diapause process of B. mori eggs. To our knowledge, this is the first study to demonstrate the potential correlation between bombyxin/Akt signaling and the embryonic diapause process.
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Affiliation(s)
- Shi-Hong Gu
- Department of Biology, National Museum of Natural Science, 1 Kuan-Chien Road, Taichung 404, Taiwan, ROC.
| | - Pei-Ling Lin
- Department of Biology, National Museum of Natural Science, 1 Kuan-Chien Road, Taichung 404, Taiwan, ROC
| | - Hsiao-Yen Hsieh
- Department of Biology, National Museum of Natural Science, 1 Kuan-Chien Road, Taichung 404, Taiwan, ROC
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14
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Akizuki K, Kinumi T, Ono A, Senga Y, Osawa J, Shigeri Y, Ishida A, Kameshita I, Sueyoshi N. Autoactivation of C-terminally truncated Ca2+/calmodulin-dependent protein kinase (CaMK) Iδ via CaMK kinase-independent autophosphorylation. Arch Biochem Biophys 2019; 668:29-38. [DOI: 10.1016/j.abb.2019.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/25/2019] [Accepted: 05/05/2019] [Indexed: 01/01/2023]
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15
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Harrington L, Alexander LT, Knapp S, Bayley H. Single-Molecule Protein Phosphorylation and Dephosphorylation by Nanopore Enzymology. ACS NANO 2019; 13:633-641. [PMID: 30588793 DOI: 10.1021/acsnano.8b07697] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Reversible protein phosphorylation plays a crucial and ubiquitous role in the control of almost all cellular processes. The interplay of protein kinases and phosphatases acting in opposition ensures tight dynamic control of protein phosphorylation states within the cell. Previously, engineered α-hemolysin pores bearing kinase substrate peptides have been developed as single-molecule stochastic sensors for protein kinases. Here, we have used these pores to observe, label-free, the phosphorylation and dephosphorylation of a single substrate molecule. Further, we investigated the effect of Mg2+ and Mn2+ upon substrate and product binding and found that Mn2+ relaxes active-site specificity toward nucleotides and enhances product binding. In doing so, we demonstrate the power and versatility of nanopore enzymology to scrutinize a critical post-translational modification.
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Affiliation(s)
- Leon Harrington
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Leila T Alexander
- Nuffield Department of Clinical Medicine, Structural Genomics Consortium and Target Discovery Institute , University of Oxford , Oxford OX3 7DQ , United Kingdom
| | - Stefan Knapp
- Nuffield Department of Clinical Medicine, Structural Genomics Consortium and Target Discovery Institute , University of Oxford , Oxford OX3 7DQ , United Kingdom
| | - Hagan Bayley
- Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
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16
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González-Mariscal I, Martin-Montalvo A, Vazquez-Fonseca L, Pomares-Viciana T, Sánchez-Cuesta A, Fernández-Ayala DJ, Navas P, Santos-Ocana C. The mitochondrial phosphatase PPTC7 orchestrates mitochondrial metabolism regulating coenzyme Q10 biosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1235-1248. [DOI: 10.1016/j.bbabio.2018.09.369] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/20/2018] [Accepted: 09/20/2018] [Indexed: 12/22/2022]
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17
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Jang S, Gornicki P, Marjanovic J, Bass E, P Iurcotta T, Rodriguez P, Austin J, Haselkorn R. Activity and structure of human acetyl-CoA carboxylase targeted by a specific inhibitor. FEBS Lett 2018; 592:2048-2058. [PMID: 29772612 DOI: 10.1002/1873-3468.13097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/20/2018] [Accepted: 05/03/2018] [Indexed: 01/01/2023]
Abstract
We have studied a series of human acetyl-CoA carboxylase (ACC) 1 and ACC2 proteins with deletions and/or Ser to Ala substitutions of the known phosphorylation sites. In vitro dephosphorylation/phosphorylation experiments reveal a substantial level of phosphorylation of human ACCs produced in insect cells. Our results are consistent with AMPK phosphorylation of Ser29 , Ser80 , Ser1,201 , and Ser1,216 . Phosphorylation of the N-terminal regulatory domain decreases ACC1 activity, while phosphorylation of residues in the ACC central domain has no effect. Inhibition of the activity by phosphorylation is significantly more profound at citrate concentrations below 2 mm. Furthermore, deletion of the N-terminal domain facilitates structural changes induced by citrate, including conversion of ACC dimers to linear polymers. We have also identified ACC2 amino acid mutations affecting specific inhibition of the isozyme by compound CD-017-0191. They form two clusters separated by 60-90 Å: one located in the vicinity of the BC active site and the other one in the vicinity of the ACC1 phosphorylation sites in the central domain, suggesting a contribution of the interface of two ACC dimers in the polymer to the inhibitor binding site.
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Affiliation(s)
- SoRi Jang
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Piotr Gornicki
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Jasmina Marjanovic
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Ethan Bass
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Toni P Iurcotta
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Pedro Rodriguez
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Jotham Austin
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
| | - Robert Haselkorn
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
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18
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Akizuki K, Toyama T, Yamashita M, Sugiyama Y, Ishida A, Kameshita I, Sueyoshi N. Facile preparation of highly active casein kinase 1 using Escherichia coli constitutively expressing lambda phosphatase. Anal Biochem 2018; 549:99-106. [DOI: 10.1016/j.ab.2018.03.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 11/27/2022]
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19
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Bhoir S, Shaik A, Thiruvenkatam V, Kirubakaran S. High yield bacterial expression, purification and characterisation of bioactive Human Tousled-like Kinase 1B involved in cancer. Sci Rep 2018; 8:4796. [PMID: 29555908 PMCID: PMC5859067 DOI: 10.1038/s41598-018-22744-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/28/2018] [Indexed: 12/14/2022] Open
Abstract
Human Tousled-like kinases (TLKs) are highly conserved serine/threonine protein kinases responsible for cell proliferation, DNA repair, and genome surveillance. Their possible involvement in cancer via efficient DNA repair mechanisms have made them clinically relevant molecular targets for anticancer therapy. Innovative approaches in chemical biology have played a key role in validating the importance of kinases as molecular targets. However, the detailed understanding of the protein structure and the mechanisms of protein-drug interaction through biochemical and biophysical techniques demands a method for the production of an active protein of exceptional stability and purity on a large scale. We have designed a bacterial expression system to express and purify biologically active, wild-type Human Tousled-like Kinase 1B (hTLK1B) by co-expression with the protein phosphatase from bacteriophage λ. We have obtained remarkably high amounts of the soluble and homogeneously dephosphorylated form of biologically active hTLK1B with our unique, custom-built vector design strategy. The recombinant hTLK1B can be used for the structural studies and may further facilitate the development of new TLK inhibitors for anti-cancer therapy using a structure-based drug design approach.
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Affiliation(s)
- Siddhant Bhoir
- Dicipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Simkheda, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Althaf Shaik
- Dicipline of Chemistry, Indian Institute of Technology Gandhinagar, Simkheda, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Vijay Thiruvenkatam
- Dicipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Simkheda, Palaj, Gandhinagar, 382355, Gujarat, India.
- Dicipline of Physics, Indian Institute of Technology Gandhinagar, Simkheda, Palaj, Gandhinagar, 382355, Gujarat, India.
| | - Sivapriya Kirubakaran
- Dicipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Simkheda, Palaj, Gandhinagar, 382355, Gujarat, India.
- Dicipline of Chemistry, Indian Institute of Technology Gandhinagar, Simkheda, Palaj, Gandhinagar, 382355, Gujarat, India.
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20
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Gu SH, Li G, Hsieh HY, Lin PL, Li S. Stimulation of JNK Phosphorylation by the PTTH in Prothoracic Glands of the Silkworm, Bombyx mori. Front Physiol 2018; 9:43. [PMID: 29459829 PMCID: PMC5807416 DOI: 10.3389/fphys.2018.00043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/12/2018] [Indexed: 01/06/2023] Open
Abstract
In this study, phosphorylation of c-Jun N-terminal kinase (JNK) by the prothoracicotropic hormone (PTTH) was investigated in prothoracic glands (PGs) of the silkworm, Bombyx mori. Results showed that JNK phosphorylation was stimulated by the PTTH in time- and dose-dependent manners. In vitro activation of JNK phosphorylation in PGs by the PTTH was also confirmed in an in vivo experiment, in which a PTTH injection greatly increased JNK phosphorylation in PGs of day-6 last instar larvae. JNK phosphorylation caused by PTTH stimulation was greatly inhibited by U73122, a potent and specific inhibitor of phospholipase C (PLC) and an increase in JNK phosphorylation was also detected when PGs were treated with agents (either A23187 or thapsigargin) that directly elevated the intracellular Ca2+ concentration, thereby indicating involvement of PLC and Ca2+. Pretreatment with an inhibitor (U0126) of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) and an inhibitor (LY294002) of phosphoinositide 3-kinase (PI3K) failed to significantly inhibit PTTH-stimulated JNK phosphorylation, indicating that ERK and PI3K were not related to JNK. We further investigated the effect of modulation of the redox state on JNK phosphorylation. In the presence of either an antioxidant (N-acetylcysteine, NAC) or diphenylene iodonium (DPI), PTTH-stimulated JNK phosphorylation was blocked. The JNK kinase inhibitor, SP600125, markedly inhibited PTTH-stimulated JNK phosphorylation and ecdysteroid synthesis. The kinase assay of JNK in PGs confirmed its stimulation by PTTH and inhibition by SP600125. Moreover, PTTH treatment did not affect JNK or Jun mRNA expressions. Based on these findings, we concluded that PTTH stimulates JNK phosphorylation in Ca2+- and PLC-dependent manners and that the redox-regulated JNK signaling pathway is involved in PTTH-stimulated ecdysteroid synthesis in B. mori PGs.
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Affiliation(s)
- Shi-Hong Gu
- Department of Biology, National Museum of Natural Science, Taichung, Taiwan
| | - Gen Li
- Graduate School of Engineering, Chiba University, Chiba, Japan
| | - Hsiao-Yen Hsieh
- Department of Biology, National Museum of Natural Science, Taichung, Taiwan
| | - Pei-Ling Lin
- Department of Biology, National Museum of Natural Science, Taichung, Taiwan
| | - Sheng Li
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Sciences and School of Life Sciences, South China Normal University, Guangzhou, China
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21
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WeiΔ LM, Hugle M, Fulda S. Eribulin alone or in combination with the PLK1 inhibitor BI 6727 triggers intrinsic apoptosis in Ewing sarcoma cell lines. Oncotarget 2017; 8:52445-52456. [PMID: 28881742 PMCID: PMC5581041 DOI: 10.18632/oncotarget.17190] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/02/2017] [Indexed: 11/25/2022] Open
Abstract
In this study, we investigated the molecular mechanisms of eribulin-induced cell death and its therapeutic potential in combination with the PLK1 inhibitor BI 6727 in Ewing sarcoma (ES). Here, we show that eribulin triggers cell death in a dose-dependent manner in a panel of ES cell lines. In addition, eribulin at subtoxic, low nanomolar concentrations acts in concert with BI 6727 to induce cell death and to suppress long-term clonogenic survival. Mechanistic studies reveal that eribulin monotherapy at cytotoxic concentrations and co-treatment with eribulin at subtoxic concentrations together with BI 6727 arrest cells in the M phase of the cell cycle prior to the onset of cell death. This mitotic arrest is followed by increased phosphorylation of BCL-2 and BCL-xL as well as downregulation of MCL-1, suggesting inactivation of these antiapoptotic BCL-2 family proteins. Consistently, eribulin monotherapy and eribulin/BI 6727 co-treatment trigger activation of BAX, a key proapoptotic BCL-2 family protein, and increase proteolytic activation of caspase-9 and -3. Importantly, overexpression of BCL-2 or addition of the broad-range caspase inhibitor zVAD.fmk significantly rescue eribulin- as well as eribulin/BI 6727-induced cell death. Together, these findings demonstrate that eribulin induces cell death via the intrinsic pathway of apoptosis in ES cells, both alone at cytotoxic concentrations and in combination with BI 6727 at subtoxic concentrations. Thus, our study highlights the therapeutic potential of eribulin for the treatment of ES alone or in rational combination therapies.
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Affiliation(s)
- Lilly Magdalena WeiΔ
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Manuela Hugle
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany
| | - Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
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22
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Molecular Mechanism of Pin1–Tau Recognition and Catalysis. J Mol Biol 2016; 428:1760-75. [DOI: 10.1016/j.jmb.2016.03.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 02/06/2023]
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23
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Engelberg K, Ivey FD, Lin A, Kono M, Lorestani A, Faugno-Fusci D, Gilberger TW, White M, Gubbels MJ. A MORN1-associated HAD phosphatase in the basal complex is essential for Toxoplasma gondii daughter budding. Cell Microbiol 2016; 18:1153-71. [PMID: 26840427 DOI: 10.1111/cmi.12574] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/24/2015] [Accepted: 01/19/2016] [Indexed: 12/30/2022]
Abstract
Apicomplexan parasites replicate by several budding mechanisms with two well-characterized examples being Toxoplasma endodyogeny and Plasmodium schizogony. Completion of budding requires the tapering of the nascent daughter buds toward the basal end, driven by contraction of the basal complex. This contraction is not executed by any of the known cell division associated contractile mechanisms and in order to reveal new components of the unusual basal complex we performed a yeast two-hybrid screen with its major scaffolding protein, TgMORN1. Here we report on a conserved protein with a haloacid dehalogenase (HAD) phosphatase domain, hereafter named HAD2a, identified by yeast two-hybrid. HAD2a has demonstrated enzyme-activity in vitro, localizes to the nascent daughter buds, and co-localizes with MORN1 to the basal complex during its contraction. Conditional knockout of HAD2a in Toxoplasma interferes with basal complex assembly, which leads to incomplete cytokinesis and conjoined daughters that ultimately results in disrupted proliferation. In Plasmodium, we further confirmed localization of the HAD2a ortholog to the basal complex toward the end of schizogony. In conclusion, our work highlights an essential role for this HAD phosphatase across apicomplexan budding and suggests a regulatory mechanism of differential phosphorylation on the structure and/or contractile function of the basal complex.
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Affiliation(s)
- Klemens Engelberg
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - F Douglas Ivey
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Angela Lin
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Maya Kono
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | | | - Dave Faugno-Fusci
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Tim-Wolf Gilberger
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,M.G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.,Center for Structural Systems Biology, Hamburg, Germany
| | - Michael White
- Departments of Molecular Medicine & Global Health, Florida Center for Drug Discovery and Innovation, Colleges of Medicine and Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Marc-Jan Gubbels
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
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24
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Meitinger F, Palani S, Pereira G. Detection of Phosphorylation Status of Cytokinetic Components. Methods Mol Biol 2016; 1369:219-37. [PMID: 26519316 DOI: 10.1007/978-1-4939-3145-3_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Yeast cells can be easily cultured, synchronized, and genetically modified making them a convenient model system to study molecular mechanisms underlying cytokinesis. Here, we describe simple methods that allow the analysis of the phosphorylation profile of cytokinetic proteins, both in vivo and in vitro, using standard laboratory equipment. In addition, we compare the ability of three different, standard, and optimized acrylamide gel conditions to separate phosphorylated forms, using the protein Inn1 as an example.
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Affiliation(s)
- Franz Meitinger
- DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), University of Heidelberg, Im Neuenheimer Feld 581, Heidelberg, 69120, Germany.,Ludwig Institute for Cancer Research, 9500 Gilman Drive, CMM East, La Jolla, CA, 92093, USA
| | - Saravanan Palani
- Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Gislene Pereira
- DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), University of Heidelberg, Im Neuenheimer Feld 581, Heidelberg, 69120, Germany.
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25
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Phosphorylation-mediated RNA/peptide complex coacervation as a model for intracellular liquid organelles. Nat Chem 2015; 8:129-37. [PMID: 26791895 DOI: 10.1038/nchem.2414] [Citation(s) in RCA: 363] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 11/03/2015] [Indexed: 02/08/2023]
Abstract
Biological cells are highly organized, with numerous subcellular compartments. Phosphorylation has been hypothesized as a means to control the assembly/disassembly of liquid-like RNA- and protein-rich intracellular bodies, or liquid organelles, that lack delimiting membranes. Here, we demonstrate that charge-mediated phase separation, or complex coacervation, of RNAs with cationic peptides can generate simple model liquid organelles capable of reversibly compartmentalizing biomolecules. Formation and dissolution of these liquid bodies was controlled by changes in peptide phosphorylation state using a kinase/phosphatase enzyme pair. The droplet-generating phase transition responded to modification of even a single serine residue. Electrostatic interactions between the short cationic peptides and the much longer polyanionic RNAs drove phase separation. Coacervates were also formed on silica beads, a primitive model for localization at specific intracellular sites. This work supports phosphoregulation of complex coacervation as a viable mechanism for dynamic intracellular compartmentalization in membraneless organelles.
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26
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Munson MJ, Allen GF, Toth R, Campbell DG, Lucocq JM, Ganley IG. mTOR activates the VPS34-UVRAG complex to regulate autolysosomal tubulation and cell survival. EMBO J 2015; 34:2272-90. [PMID: 26139536 PMCID: PMC4585463 DOI: 10.15252/embj.201590992] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 05/16/2015] [Accepted: 06/04/2015] [Indexed: 02/01/2023] Open
Abstract
Lysosomes are essential organelles that function to degrade and recycle unwanted, damaged and toxic biological components. Lysosomes also act as signalling platforms in activating the nutrient-sensing kinase mTOR. mTOR regulates cellular growth, but it also helps to maintain lysosome identity by initiating lysosomal tubulation through a process termed autophagosome-lysosome reformation (ALR). Here we identify a lysosomal pool of phosphatidylinositol 3-phosphate that, when depleted by specific inhibition of the class III phosphoinositide 3-kinase VPS34, results in prolonged lysosomal tubulation. This tubulation requires mTOR activity, and we identified two direct mTOR phosphorylation sites on UVRAG (S550 and S571) that activate VPS34. Loss of these phosphorylation sites reduced VPS34 lipid kinase activity and resulted in an increase in number and length of lysosomal tubules. In cells in which phosphorylation at these UVRAG sites is disrupted, the result of impaired lysosomal tubulation alongside ALR activation is massive cell death. Our data imply that ALR is critical for cell survival under nutrient stress and that VPS34 is an essential regulatory element in this process.
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Affiliation(s)
- Michael J Munson
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
| | - George Fg Allen
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
| | - Rachel Toth
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
| | - David G Campbell
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
| | - John M Lucocq
- School of Medicine University of St Andrews, St Andrews, UK
| | - Ian G Ganley
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
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Uncoupling Stress-Inducible Phosphorylation of Heat Shock Factor 1 from Its Activation. Mol Cell Biol 2015; 35:2530-40. [PMID: 25963659 DOI: 10.1128/mcb.00816-14] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 05/04/2015] [Indexed: 12/31/2022] Open
Abstract
In mammals the stress-inducible expression of genes encoding heat shock proteins is under the control of the heat shock transcription factor 1 (HSF1). Activation of HSF1 is a multistep process, involving trimerization, acquisition of DNA-binding and transcriptional activities, which coincide with several posttranslational modifications. Stress-inducible phosphorylation of HSF1, or hyperphosphorylation, which occurs mainly within the regulatory domain (RD), has been proposed as a requirement for HSF-driven transcription and is widely used for assessing HSF1 activation. Nonetheless, the contribution of hyperphosphorylation to the activity of HSF1 remains unknown. In this study, we generated a phosphorylation-deficient HSF1 mutant (HSF1Δ∼PRD), where the 15 known phosphorylation sites within the RD were disrupted. Our results show that the phosphorylation status of the RD does not affect the subcellular localization and DNA-binding activity of HSF1. Surprisingly, under stress conditions, HSF1Δ∼PRD is a potent transactivator of both endogenous targets and a reporter gene, and HSF1Δ∼PRD has a reduced activation threshold. Our results provide the first direct evidence for uncoupling stress-inducible phosphorylation of HSF1 from its activation, and we propose that the phosphorylation signature alone is not an appropriate marker for HSF1 activity.
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28
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Wang Y, Wang Y, Zhao YB, Chen DM, Han ZH, Zhang XZ. Protein phosphorylation differs significantly among ontogenetic phases in Malus seedlings. Proteome Sci 2014; 12:31. [PMID: 24904238 PMCID: PMC4046019 DOI: 10.1186/1477-5956-12-31] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/14/2014] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Although protein phosphorylation is an important post-translational modification affecting protein function and metabolism, dynamic changes in this process during ontogenesis remain unexplored in woody angiosperms. METHODS Phosphorylated proteins from leaves of three apple seedlings at juvenile, adult vegetative and reproductive stages were extracted and subjected to alkaline phosphatase pre-treatment. After separating the proteins by two-dimensional gel electrophoresis and phosphoprotein-specific Pro-Q Diamond staining, differentially expressed phosphoproteins were identified by MALDI-TOF-TOF mass spectrometry. RESULTS A total of 107 phosphorylated protein spots on nine gels (three ontogenetic phases × three seedlings) were identified by MALDI-TOF-TOF mass spectrometry. The 55 spots of ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) large-chain fragments varied significantly in protein abundance and degree of phosphorylation among ontogenetic phases. Abundances of the 27 spots corresponding to Rubisco activase declined between juvenile and reproductive phases. More extensively, phosphorylated β-tubulin chain spots with lower isoelectric points were most abundant during juvenile and adult vegetative phases. CONCLUSIONS Protein phosphorylation varied significantly during vegetative phase change and floral transition in apple seedlings. Most of the observed changes were consistent among seedlings and between hybrid populations.
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Affiliation(s)
- Yan Wang
- Institute for Horticultural Plants, China Agricultural University, Beijing 100193, China
| | - Yi Wang
- Institute for Horticultural Plants, China Agricultural University, Beijing 100193, China
| | - Yong Bo Zhao
- Changli Institute of Pomology, Hebei Academy of Agricultural and Forestry Sciences, Changli 066600, China
| | - Dong Mei Chen
- Changli Institute of Pomology, Hebei Academy of Agricultural and Forestry Sciences, Changli 066600, China
| | - Zhen Hai Han
- Institute for Horticultural Plants, China Agricultural University, Beijing 100193, China
| | - Xin Zhong Zhang
- Institute for Horticultural Plants, China Agricultural University, Beijing 100193, China
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29
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White-Grindley E, Li L, Mohammad Khan R, Ren F, Saraf A, Florens L, Si K. Contribution of Orb2A stability in regulated amyloid-like oligomerization of Drosophila Orb2. PLoS Biol 2014; 12:e1001786. [PMID: 24523662 PMCID: PMC3921104 DOI: 10.1371/journal.pbio.1001786] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 12/31/2013] [Indexed: 12/13/2022] Open
Abstract
How learned experiences persist as memory for a long time is an important question. In Drosophila the persistence of memory is dependent upon amyloid-like oligomers of the Orb2 protein. However, it is not clear how the conversion of Orb2 to the amyloid-like oligomeric state is regulated. The Orb2 has two protein isoforms, and the rare Orb2A isoform is critical for oligomerization of the ubiquitous Orb2B isoform. Here, we report the discovery of a protein network comprised of protein phosphatase 2A (PP2A), Transducer of Erb-B2 (Tob), and Lim Kinase (LimK) that controls the abundance of Orb2A. PP2A maintains Orb2A in an unphosphorylated and unstable state, whereas Tob-LimK phosphorylates and stabilizes Orb2A. Mutation of LimK abolishes activity-dependent Orb2 oligomerization in the adult brain. Moreover, Tob-Orb2 association is modulated by neuronal activity and Tob activity in the mushroom body is required for stable memory formation. These observations suggest that the interplay between PP2A and Tob-LimK activity may dynamically regulate Orb2 amyloid-like oligomer formation and the stabilization of memories.
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Affiliation(s)
- Erica White-Grindley
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Liying Li
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Repon Mohammad Khan
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Fengzhen Ren
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Anita Saraf
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Kausik Si
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- * E-mail:
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30
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Orrego PR, Olivares H, Cordero EM, Bressan A, Cortez M, Sagua H, Neira I, González J, da Silveira JF, Yoshida N, Araya JE. A cytoplasmic new catalytic subunit of calcineurin in Trypanosoma cruzi and its molecular and functional characterization. PLoS Negl Trop Dis 2014; 8:e2676. [PMID: 24498455 PMCID: PMC3907409 DOI: 10.1371/journal.pntd.0002676] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 12/18/2013] [Indexed: 12/20/2022] Open
Abstract
Parasitological cure for Chagas disease is considered extremely difficult to achieve because of the lack of effective chemotherapeutic agents against Trypanosoma cruzi at different stages of infection. There are currently only two drugs available. These have several limitations and can produce serious side effects. Thus, new chemotherapeutic targets are much sought after. Among T. cruzi components involved in key processes such as parasite proliferation and host cell invasion, Ca(2+)-dependent molecules play an important role. Calcineurin (CaN) is one such molecule. In this study, we cloned a new isoform of the gene coding for CL strain catalytic subunit CaNA (TcCaNA2) and characterized it molecularly and functionally. There is one copy of the TcCaNA2 gene per haploid genome. It is constitutively transcribed in all T. cruzi developmental forms and is localized predominantly in the cytosol. In the parasite, TcCaNA2 is associated with CaNB. The recombinant protein TcCaNA2 has phosphatase activity that is enhanced by Mn(2+)/Ni(2+). The participation of TcCaNA2 in target cell invasion by metacyclic trypomastigotes was also demonstrated. Metacyclic forms with reduced TcCaNA2 expression following treatment with morpholino antisense oligonucleotides targeted to TcCaNA2 invaded HeLa cells at a lower rate than control parasites treated with morpholino sense oligonucleotides. Similarly, the decreased expression of TcCaNA2 following treatment with antisense morpholino oligonucleotides partially affected the replication of epimastigotes, although to a lesser extent than the decrease in expression following treatment with calcineurin inhibitors. Our findings suggest that the calcineurin activities of TcCaNA2/CaNB and TcCaNA/CaNB, which have distinct cellular localizations (the cytoplasm and the nucleus, respectively), may play a critical role at different stages of T. cruzi development, the former in host cell invasion and the latter in parasite multiplication.
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Affiliation(s)
- Patricio R. Orrego
- Department of Medical Technology, University of Antofagasta, Antofagasta, Chile
| | - Héctor Olivares
- Biomedical Department, University of Antofagasta, Antofagasta, Chile
| | - Esteban M. Cordero
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Albert Bressan
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Mauro Cortez
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Hernán Sagua
- Department of Medical Technology, University of Antofagasta, Antofagasta, Chile
| | - Ivan Neira
- Department of Medical Technology, University of Antofagasta, Antofagasta, Chile
| | - Jorge González
- Department of Medical Technology, University of Antofagasta, Antofagasta, Chile
| | - José Franco da Silveira
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Nobuko Yoshida
- Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Jorge E. Araya
- Department of Medical Technology, University of Antofagasta, Antofagasta, Chile
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31
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The IRAK homolog Pelle is the functional counterpart of IκB kinase in the Drosophila Toll pathway. PLoS One 2013; 8:e75150. [PMID: 24086459 PMCID: PMC3781037 DOI: 10.1371/journal.pone.0075150] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 08/09/2013] [Indexed: 12/30/2022] Open
Abstract
Toll receptors transduce signals that activate Rel-family transcription factors, such as NF-κB, by directing proteolytic degradation of inhibitor proteins. In mammals, the IκB Kinase (IKK) phosphorylates the inhibitor IκBα. A βTrCP protein binds to phosphorylated IκBα, triggering ubiquitination and proteasome mediated degradation. In Drosophila, Toll signaling directs Cactus degradation via a sequence motif that is highly similar to that in IκBα, but without involvement of IKK. Here we show that Pelle, the homolog of a mammalian regulator of IKK, acts as a Cactus kinase. We further find that the fly βTrCP protein Slimb is required in cultured cells to mediate Cactus degradation. These findings enable us for the first time to trace an uninterrupted pathway from the cell surface to the nucleus for Drosophila Toll signaling.
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32
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Gu SH, Hsieh YC, Young SC, Lin PL. Involvement of phosphorylation of adenosine 5'-monophosphate-activated protein kinase in PTTH-stimulated ecdysteroidogenesis in prothoracic glands of the silkworm, Bombyx mori. PLoS One 2013; 8:e63102. [PMID: 23671658 PMCID: PMC3650048 DOI: 10.1371/journal.pone.0063102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/28/2013] [Indexed: 12/25/2022] Open
Abstract
In this study, we investigated inhibition of the phosphorylation of adenosine 5′-monophosphate-activated protein kinase (AMPK) by prothoracicotropic hormone (PTTH) in prothoracic glands of the silkworm, Bombyx mori. We found that treatment with PTTH in vitro inhibited AMPK phosphorylation in time- and dose-dependent manners, as seen on Western blots of glandular lysates probed with antibody directed against AMPKα phosphorylated at Thr172. Moreover, in vitro inhibition of AMPK phosphorylation by PTTH was also verified by in vivo experiments: injection of PTTH into day 7 last instar larvae greatly inhibited glandular AMPK phosphorylation. PTTH-inhibited AMPK phosphorylation appeared to be partially reversed by treatment with LY294002, indicating involvement of phosphatidylinositol 3-kinase (PI3K) signaling. A chemical activator of AMPK (5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside, AICAR) increased both basal and PTTH-inhibited AMPK phosphorylation. Treatment with AICAR also inhibited PTTH-stimulated ecdysteroidogenesis of prothoracic glands. The mechanism underlying inhibition of PTTH-stimulated ecdysteroidogenesis by AICAR was further investigated by determining the phosphorylation of eIF4E-binding protein (4E-BP) and p70 ribosomal protein S6 kinase (S6K), two known downstream signaling targets of the target of rapamycin complex 1 (TORC1). Upon treatment with AICAR, decreases in PTTH-stimulated phosphorylation of 4E-BP and S6K were detected. In addition, treatment with AICAR did not affect PTTH-stimulated extracellular signal-regulated kinase (ERK) phosphorylation, indicating that AMPK phosphorylation is not upstream signaling for ERK phosphorylation. Examination of gene expression levels of AMPKα, β, and γ by quantitative real-time PCR (qRT-PCR) showed that PTTH did not affect AMPK transcription. From these results, it is assumed that inhibition of AMPK phosphorylation, which lies upstream of PTTH-stimulated TOR signaling, may play a role in PTTH stimulation of ecdysteroidogenesis.
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Affiliation(s)
- Shi-Hong Gu
- Department of Zoology, National Museum of Natural Science, Taichung, Taiwan, Republic of China.
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33
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Wang LK, Smith P, Shuman S. Structure and mechanism of the 2',3' phosphatase component of the bacterial Pnkp-Hen1 RNA repair system. Nucleic Acids Res 2013; 41:5864-73. [PMID: 23595150 PMCID: PMC3675462 DOI: 10.1093/nar/gkt221] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Pnkp is the end-healing and end-sealing component of an RNA repair system present in diverse bacteria from many phyla. Pnkp is composed of three catalytic modules: an N-terminal polynucleotide 5′ kinase, a central 2′,3′ phosphatase and a C-terminal ligase. The phosphatase module is a Mn2+-dependent phosphodiesterase–monoesterase that dephosphorylates 2′,3′-cyclic phosphate RNA ends. Here we report the crystal structure of the phosphatase domain of Clostridium thermocellum Pnkp with Mn2+ and citrate in the active site. The protein consists of a core binuclear metallo-phosphoesterase fold (exemplified by bacteriophage λ phosphatase) embellished by distinctive secondary structure elements. The active site contains a single Mn2+ in an octahedral coordination complex with Asp187, His189, Asp233, two citrate oxygens and a water. The citrate fills the binding site for the scissile phosphate, wherein it is coordinated by Arg237, Asn263 and His264. The citrate invades the site normally occupied by a second metal (engaged by Asp233, Asn263, His323 and His376), and thereby dislocates His376. A continuous tract of positive surface potential flanking the active site suggests an RNA binding site. The structure illuminates a large body of mutational data regarding the metal and substrate specificity of Clostridium thermocellum Pnkp phosphatase.
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Affiliation(s)
- Li Kai Wang
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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34
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Parthasarathy RN, Lakshmanan J, Thangavel M, Seelan RS, Stagner JI, Janckila AJ, Vadnal RE, Casanova MF, Parthasarathy LK. Rat brain myo-inositol 3-phosphate synthase is a phosphoprotein. Mol Cell Biochem 2013; 378:83-9. [PMID: 23504145 DOI: 10.1007/s11010-013-1597-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 02/22/2013] [Indexed: 11/29/2022]
Abstract
The therapeutic effects of lithium in bipolar disorder are poorly understood. Lithium decreases free inositol levels by inhibiting inositol monophosphatase 1 and myo-inositol 3-phosphate synthase (IPS). In this study, we demonstrate for the first time that IPS can be phosphorylated. This was evident when purified rat IPS was dephosphorylated by lambda protein phosphatase and analyzed by phospho-specific ProQ-Diamond staining and Western blot analysis. These techniques demonstrated a mobility shift consistent with IPS being phosphorylated. Mass spectral analysis revealed that Serine-524 (S524), which resides in the hinge region derived from exon 11 of the gene, is the site for phosphorylation. Further, an antibody generated against a synthetic peptide of IPS containing monophosphorylated-S524, was able to discriminate the phosphorylated and non-phosphorylated forms of IPS. The phosphoprotein is found in the brain and testis, but not in the intestine. The intestinal IPS isoform lacks the peptide bearing S524, and hence, cannot be phosphorylated. Evidences suggest that IPS is monophosphorylated at S524 and that the removal of this phosphate does not alter its enzymatic activity. These observations suggest a novel function for IPS in brain and other tissues. Future studies should resolve the functional role of phospho-IPS in brain inositol signaling.
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Affiliation(s)
- R N Parthasarathy
- Molecular Neuroscience and Bioinformatics Laboratories, Mental Health, Behavioral Science and Research Services, Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA.
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Abstract
Post-translational modifications of proteins can have dramatic effect on the function of proteins. Significant research effort has gone into understanding the effect of particular modifications on protein parameters. In the present paper, I review some of the recently developed tools for the synthesis of proteins modified with single post-translational modifications at specific sites in the protein, such as amber codon suppression technologies, tag and modify, and native chemical ligation.
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36
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Ahsan N, Huang Y, Tovar-Mendez A, Swatek KN, Zhang J, Miernyk JA, Xu D, Thelen JJ. A versatile mass spectrometry-based method to both identify kinase client-relationships and characterize signaling network topology. J Proteome Res 2013; 12:937-48. [PMID: 23270405 PMCID: PMC3888875 DOI: 10.1021/pr3009995] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While more than a thousand protein kinases (PK) have been identified in the Arabidopsis thaliana genome, relatively little progress has been made toward identifying their individual client proteins. Herein we describe the use of a mass spectrometry-based in vitro phosphorylation strategy, termed Kinase Client assay (KiC assay), to study a targeted-aspect of signaling. A synthetic peptide library comprising 377 in vivo phosphorylation sequences from developing seed was screened using 71 recombinant A. thaliana PK. Among the initial results, we identified 23 proteins as putative clients of 17 PK. In one instance protein phosphatase inhibitor-2 (AtPPI-2) was phosphorylated at multiple-sites by three distinct PK, casein kinase1-like 10, AME3, and a Ser PK-like protein. To confirm this result, full-length recombinant AtPPI-2 was reconstituted with each of these PK. The results confirmed multiple distinct phosphorylation sites within this protein. Biochemical analyses indicate that AtPPI-2 inhibits type 1 protein phosphatase (TOPP) activity, and that the phosphorylated forms of AtPPI-2 are more potent inhibitors. Structural modeling revealed that phosphorylation of AtPPI-2 induces conformational changes that modulate TOPP binding.
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Affiliation(s)
- Nagib Ahsan
- Department of Biochemistry and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211 USA
| | - Yadong Huang
- Department of Biochemistry and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211 USA
| | - Alejandro Tovar-Mendez
- Department of Biochemistry and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211 USA
| | - Kirby N. Swatek
- Department of Biochemistry and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211 USA
| | - Jingfen Zhang
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211 USA
- Department of Computer Science and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
| | - Ján A. Miernyk
- Department of Biochemistry and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
- Plant Genetics Research Unit, USDA, Agricultural Research Service, University of Missouri, Columbia, MO 65211 USA
| | - Dong Xu
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211 USA
- Department of Computer Science and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
| | - Jay J. Thelen
- Department of Biochemistry and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211 USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211 USA
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37
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Choi HJ, Zhu BT. Role of cyclin B1/Cdc2 in mediating Bcl-XL
phosphorylation and apoptotic cell death following nocodazole-induced mitotic arrest. Mol Carcinog 2012; 53:125-37. [DOI: 10.1002/mc.21956] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 07/18/2012] [Accepted: 08/01/2012] [Indexed: 12/21/2022]
Affiliation(s)
- Hye Joung Choi
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine; University of Kansas Medical Center; Kansas City Kansas
| | - Bao Ting Zhu
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine; University of Kansas Medical Center; Kansas City Kansas
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Gu SH, Yeh WL, Young SC, Lin PL, Li S. TOR signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:296-303. [PMID: 22227406 DOI: 10.1016/j.ibmb.2011.12.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 12/12/2011] [Accepted: 12/26/2011] [Indexed: 05/31/2023]
Abstract
The prothoracicotropic hormone (PTTH) is a stimulator of ecdysteroidogenesis in prothoracic gland of larval insects. Our recent studies showed that phosphoinositide 3-kinase (PI3K)/Akt signaling was involved in PTTH-stimulated ecdysteroidogenesis by Bombyx mori prothoracic glands. In the present study, downstream signaling of PI3K/Akt was further investigated. Results showed that PTTH rapidly enhanced the phosphorylation of translational repressor 4E-binding protein (4E-BP) and p70 ribosomal protein S6 kinase (S6K), two known downstream signaling targets of the target of rapamycin complex 1 (TORC1). PTTH stimulated 4E-BP phosphorylation in time- and dose-dependent manners. Injection of PTTH into day-6 last instar larvae greatly increased 4E-BP phosphorylation, verifying the in vitro effect. PTTH-stimulated 4E-BP phosphorylation was blocked by both LY294002 and wortmannin, indicating the involvement of PI3K. Mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitors (PD 98059 and U0126), did not inhibit PTTH-stimulated 4E-BP phosphorylation, implying that ERK signaling is not related to PTTH-stimulated 4E-BP phosphorylation. The phosphorylation of S6K was also stimulated by PTTH both in vitro and in vivo. PI3K signaling appears to be involved in PTTH-stimulated phosphorylation of S6K. Rapamycin, a specific inhibitor of mammalian TOR signaling attenuated PTTH-stimulated phosphorylation of 4E-BP and S6K of the glands, and greatly inhibited PTTH-stimulated ecdysteroidogenesis. Examination of gene expression levels of 4E-BP and S6K showed that PTTH inhibited mRNA levels of both 4E-BP and S6K, indicating that PTTH may exert its action at both the transcriptional and phosphorylation levels. These results suggest that PTTH/PI3K/TOR/4E-BP (S6K) signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in B. mori.
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Affiliation(s)
- Shi-Hong Gu
- Department of Zoology, National Museum of Natural Science, 1 Kuan-Chien Road, Taichung, Taiwan 404, ROC.
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Abstract
The serine/threonine kinase Akt functions in multiple cellular processes, including cell survival and tumor development. Studies of the mechanisms that negatively regulate Akt have focused on dephosphorylation-mediated inactivation. In this study, we identified a negative regulator of Akt, MULAN, which possesses both a RING finger domain and E3 ubiquitin ligase activity. Akt was found to directly interact with MULAN and to be ubiquitinated by MULAN in vitro and in vivo. Other molecular assays demonstrated that phosphorylated Akt is a substantive target for both interaction with MULAN and ubiquitination by MULAN. The results of the functional studies suggest that the degradation of Akt by MULAN suppresses cell proliferation and viability. These data provide insight into the Akt ubiquitination signaling network.
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40
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Huang XL, Zhang JZ. Hydrolysis of glucose-6-phosphate in aged, acid-forced hydrolysed nanomolar inorganic iron solutions—an inorganic biocatalyst? RSC Adv 2012. [DOI: 10.1039/c1ra00353d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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41
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Weber G, Cristão VF, de L Alves F, Santos KF, Holton N, Rappsilber J, Beggs JD, Wahl MC. Mechanism for Aar2p function as a U5 snRNP assembly factor. Genes Dev 2011; 25:1601-12. [PMID: 21764848 DOI: 10.1101/gad.635911] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Little is known about how particle-specific proteins are assembled on spliceosomal small nuclear ribonucleoproteins (snRNPs). Brr2p is a U5 snRNP-specific RNA helicase required for spliceosome catalytic activation and disassembly. In yeast, the Aar2 protein is part of a cytoplasmic precursor U5 snRNP that lacks Brr2p and is replaced by Brr2p in the nucleus. Here we show that Aar2p and Brr2p bind to different domains in the C-terminal region of Prp8p; Aar2p interacts with the RNaseH domain, whereas Brr2p interacts with the Jab1/MPN domain. These domains are connected by a long, flexible linker, but the Aar2p-RNaseH complex sequesters the Jab1/MPN domain, thereby preventing binding by Brr2p. Aar2p is phosphorylated in vivo, and a phospho-mimetic S253E mutation in Aar2p leads to disruption of the Aar2p-Prp8p complex in favor of the Brr2p-Prp8p complex. We propose a model in which Aar2p acts as a phosphorylation-controlled U5 snRNP assembly factor that regulates the incorporation of the particle-specific Brr2p. The purpose of this regulation may be to safeguard against nonspecific RNA binding to Prp8p and/or premature activation of Brr2p activity.
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Affiliation(s)
- Gert Weber
- Fachbereich Biologie/Chemie/Pharmazie, Abteilung Strukturbiochemie, Freie Universität Berlin, D-14195 Berlin, Germany
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Gu SH, Young SC, Tsai WH, Lin JL, Lin PL. Involvement of 4E-BP phosphorylation in embryonic development of the silkworm, Bombyx mori. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:978-985. [PMID: 21600900 DOI: 10.1016/j.jinsphys.2011.04.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 04/15/2011] [Accepted: 04/15/2011] [Indexed: 05/30/2023]
Abstract
Phosphorylation of the translational repressor 4E-binding protein (4E-BP) plays a critical role in regulating the overall translation levels in cells. In the present study, we investigated 4E-BP phosphorylation of Bombyx mori eggs by an immunoblot analysis of a conserved phospho-specific antibody to 4E-BP and demonstrated its role during embryonic development. When HCl treatment was applied to diapause-destined eggs at 20 h after oviposition, a dramatic increase in the phosphorylation of 4E-BP occurred 5 min after treatment with HCl, and high phosphorylation levels were maintained throughout embryonic stage in HCl-treated eggs compared to those in diapause (control) eggs. When HCl treatment was applied to diapause eggs on day 10 after oviposition, no dramatic activation in 4E-BP phosphorylation occurred, indicating stage-specific effects of HCl treatment. In both non-diapause eggs and eggs whose diapause had been terminated by chilling of diapausing eggs at 5°C for 70 days and then were transferred to 25°C, high phosphorylation levels of 4E-BP were also detected. Moreover, 4E-BP phosphorylation dramatically increased when dechorionated eggs were incubated in medium. The addition of rapamycin, a specific inhibitor of mammalian target of rapamycin (TOR) signaling, and LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, but not the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitor, U0126, dose-dependently inhibited 4E-BP phosphorylation in dechorionated eggs, indicating that PI3K/TOR signaling is an upstream signaling event involved in 4E-BP phosphorylation. Examination of 4E-BP gene expression levels showed no differences between treatments with HCl and water in the first hour after treatment, indicating that changes in phosphorylation of 4E-BP upon HCl treatment are mainly regulated at the post-transcriptional level. In addition, MAPK pathways and glycogen synthase kinase (GSK)-3β phosphorylation were not significantly affected in the first hour after HCl treatment. These results demonstrate that the rapid phosphorylation of 4E-BP is an early signaling event in embryonic development in the eggs whose diapause initiation was prevented by HCl treatment, thus being involved in the embryonic development of B. mori.
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Affiliation(s)
- Shi-Hong Gu
- Department of Zoology, National Museum of Natural Science, 1 Kuan-Chien Road, Taichung 404, Taiwan, ROC.
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Otani M, Taniguchi T, Sakai A, Seta J, Kadoyama K, Nakamura-Hirota T, Matsuyama S, Sano K, Takano M. Phosphoproteome Profiling Using a Fluorescent Phosphosensor Dye in Two-Dimensional Polyacrylamide Gel Electrophoresis. Appl Biochem Biotechnol 2011; 164:804-18. [DOI: 10.1007/s12010-011-9175-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 01/18/2011] [Indexed: 10/18/2022]
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Lin JL, Gu SH. Prothoracicotropic hormone induces tyrosine phosphorylation in prothoracic glands of the silkworm, Bombyx mori. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2011; 76:144-155. [PMID: 20568296 DOI: 10.1002/arch.20373] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In the present study, we investigated the tyrosine phosphorylation of Bombyx mori prothoracic glands using phosphotyrosine-specific antibodies and Western blot analysis. Results showed that prothoracicotropic hormone (PTTH) stimulates a rapid increase in tyrosine phosphorylation of at least 2 proteins in prothoracic glands, one of which was identified as extracellular signal-regulated kinase (ERK). The phosphorylation of another 120-kDa protein showed dose- and time-dependent stimulation by PTTH in vitro. In vitro activation of tyrosine phosphorylation was also verified by in vivo experiments: injection of PTTH into day-6 last-instar larvae greatly increased tyrosine phosphorylation. Treatment of prothoracic glands with the protein tyrosine phosphatase inhibitor, sodium orthovanadate, also resulted in tyrosine phosphorylation of several proteins and increased ecdysteroidogenesis. The PTTH-stimulated phosphorylation of the 120-kDa protein was markedly attenuated by genistein, a broad-spectrum tyrosine kinase inhibitor, but not by HNMPA-(AM)(3) , a specific inhibitor of insulin receptor tyrosine kinase. PP2, a more-selective inhibitor of the Src-family tyrosine kinases, partially inhibited PTTH-stimulated tyrosine phosphorylation, but not ecdysteroidogenesis. This result implies the possibility that in addition to ERK, the phosphorylation of the 120-kDa protein, which is not Src-family tyrosine kinase, is likely also involved in PTTH-stimulated ecdysteroidogenesis in B. mori.
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Affiliation(s)
- Ju-Ling Lin
- Department of Zoology, National Museum of Natural Science, Taiwan, ROC
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Kovtun O, Mureev S, Johnston W, Alexandrov K. Towards the construction of expressed proteomes using a Leishmania tarentolae based cell-free expression system. PLoS One 2010; 5:e14388. [PMID: 21203562 PMCID: PMC3006200 DOI: 10.1371/journal.pone.0014388] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 11/25/2010] [Indexed: 11/19/2022] Open
Abstract
The adaptation of organisms to a parasitic life style is often accompanied by the emergence of novel biochemical pathways absent in free-living organisms. As a result, the genomes of specialized parasitic organisms often code for a large number (>50%) of proteins with no detectable homology or predictable function. Although understanding the biochemical properties of these proteins and their roles in parasite biogenesis is the next challenge of molecular parasitology, analysis tools developed for free-living organisms are often inadequate for this purpose. Here we attempt to solve some of these problems by developing a methodology for the rapid production of expressed proteomes in cell-free systems based on parasitic organisms. To do so we take advantage of Species Independent Translational Sequences (SITS), which can efficiently mediate translation initiation in any organism. Using these sequences we developed a single-tube in vitro translation system based on the parasitic protozoan Leishmania tarentolae. We demonstrate that the system can be primed directly with SITS containing templates constructed by overlap extension PCR. To test the systems we simultaneously amplified 31 of L. tarentolae's putative translation initiation factors and phosphatases directly from the genomic DNA and subjected them to expression, purification and activity analysis. All of the amplified products produced soluble recombinant proteins, and putative phosphatases could be purified to at least 50% purity in one step. We further compared the ability of L. tarentolae and E. coli based cell-free systems to express a set of mammalian, L. tarentolae and Plasmodium falciparum Rab GTPases in functional form. We demonstrate that the L. tarentolae cell-free system consistently produced higher quality proteins than E. coli-based system. The differences were particularly pronounced in the case of open reading frames derived from P. falciparum. The implications of these developments are discussed.
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Affiliation(s)
- Oleksiy Kovtun
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Sergey Mureev
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Wayne Johnston
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Kirill Alexandrov
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- * E-mail:
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Rybakova IN, Greaser ML, Moss RL. Myosin binding protein C interaction with actin: characterization and mapping of the binding site. J Biol Chem 2010; 286:2008-16. [PMID: 21071444 DOI: 10.1074/jbc.m110.170605] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin binding protein C (MyBPC) is a multidomain protein associated with the thick filaments of striated muscle. Although both structural and regulatory roles have been proposed for MyBPC, its interactions with other sarcomeric proteins remain obscure. The current study was designed to examine the actin-binding properties of MyBPC and to define MyBPC domain regions involved in actin interaction. Here, we have expressed full-length mouse cardiac MyBPC (cMyBPC) in a baculovirus system and shown that purified cMyBPC binds actin filaments with an affinity of 4.3 ± 1.1 μM and a 1:1 molar ratio with regard to an actin protomer. The actin binding by cMyBPC is independent of protein phosphorylation status and is not significantly affected by the presence of tropomyosin and troponin on the actin filament. In addition, cMyBPC-actin interaction is not modulated by calmodulin. To determine the region of cMyBPC that is responsible for its interaction with actin, we have expressed and characterized five recombinant proteins encoding fragments of the cMyBPC sequence. Recombinant N-terminal fragments such as C0-C1, C0-C4, and C0-C5 cosediment with actin in a linear, nonsaturable manner. At the same time, MyBPC fragments lacking either the C0-C1 or C0-C4 region bind F-actin with essentially the same properties as full-length protein. Together, our results indicate that cMyBPC interacts with actin via a single, moderate affinity site localized to the C-terminal region of the protein. In contrast, certain basic regions of the N-terminal domains of MyBPC may act as small polycations and therefore bind actin via nonspecific electrostatic interactions.
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Affiliation(s)
- Inna N Rybakova
- Department of Physiology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.
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Shinkai-Ouchi F, Yamakawa Y, Hara H, Tobiume M, Nishijima M, Hanada K, Hagiwara K. Identification and structural analysis of C-terminally truncated collapsin response mediator protein-2 in a murine model of prion diseases. Proteome Sci 2010; 8:53. [PMID: 20961402 PMCID: PMC2978134 DOI: 10.1186/1477-5956-8-53] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 10/20/2010] [Indexed: 12/16/2022] Open
Abstract
Background Prion diseases are fatal neurodegenerative disorders that accompany an accumulation of the disease-associated form(s) of prion protein (PrPSc) in the central nervous system. The neuropathological changes in the brain begin with focal deposits of PrPSc, followed by pathomorphological abnormalities of axon terminal degeneration, synaptic loss, atrophy of dendritic trees, and eventual neuronal cell death in the lesions. However, the underlying molecular basis for these neuropathogenic abnormalities is not fully understood. Results In a proteomic analysis of soluble proteins in the brains of mice challenged intracerebrally with scrapie prion (Obihiro I strain), we found that the amount of the full-length form of collapsin response mediator protein-2 (CRMP-2; 61 kDa) decreased in the late stages of the disease, while the amount of its truncated form (56 kDa) increased to comparable levels observed for the full-length form. Detailed analysis by liquid chromatography-electrospray ionization-tandem mass spectrometry showed that the 56-kDa form (named CRMP-2-ΔC) lacked the sequence from serine518 to the C-terminus, including the C-terminal phosphorylation sites important for the regulation of axonal growth and axon-dendrite specification in developing neurons. The invariable size of the mRNA transcript in Northern blot analysis suggested that the truncation was due to post-translational proteolysis. By overexpression of CRMP-2-ΔC in primary cultured neurons, we observed the augmentation of the development of neurite branch tips to the same levels as for CRMP-2T514A/T555A, a non-phosphorylated mimic of the full-length protein. This suggests that the increased level of CRMP-2-ΔC in the brain modulates the integrity of neurons, and may be involved in the pathogenesis of the neuronal abnormalities observed in the late stages of the disease. Conclusions We identified the presence of CRMP-2-ΔC in the brain of a murine model of prion disease. Of note, C-terminal truncations of CRMP-2 have been recently observed in models for neurodegenerative disorders such as ischemia, traumatic brain injury, and Wallerian degeneration. While the structural identity of CRMP-2-ΔC in those models remains unknown, the present study should provide clues to the molecular pathology of degenerating neurons in prion diseases in connection with other neurodegenerative disorders.
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Affiliation(s)
- Fumiko Shinkai-Ouchi
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
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Nunes MC, Okada M, Scheidig-Benatar C, Cooke BM, Scherf A. Plasmodium falciparum FIKK kinase members target distinct components of the erythrocyte membrane. PLoS One 2010; 5:e11747. [PMID: 20668526 PMCID: PMC2909202 DOI: 10.1371/journal.pone.0011747] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 06/29/2010] [Indexed: 11/25/2022] Open
Abstract
Background Modulation of infected host cells by intracellular pathogens is a prerequisite for successful establishment of infection. In the human malaria parasite Plasmodium falciparum, potential candidates for erythrocyte remodelling include the apicomplexan-specific FIKK kinase family (20 members), several of which have been demonstrated to be transported into the erythrocyte cytoplasm via Maurer's clefts. Methodology In the current work, we have knocked out two members of this gene family (Pf fikk7.1 and Pf fikk12), whose products are localized at the inner face of the erythrocyte membrane. Both mutant parasite lines were viable and erythrocytes infected with these parasites showed no detectable alteration in their ability to adhere in vitro to endothelial receptors such as chondroitin sulfate A and CD36. However, we observed sizeable decreases in the rigidity of infected erythrocytes in both knockout lines. Mutant parasites were further analyzed using a phospho-proteomic approach, which revealed distinct phosphorylation profiles in ghost preparations of infected erythrocytes. Knockout parasites showed a significant reduction in the level of phosphorylation of a protein of approximately 80 kDa for FIKK12-KO in trophozoite stage and a large protein of about 300 kDa for FIKK7.1-KO in schizont stage. Conclusions Our results suggest that FIKK members phosphorylate different membrane skeleton proteins of the infected erythrocyte in a stage-specific manner, inducing alterations in the mechanical properties of the parasite-infected red blood cell. This suggests that these host cell modifications may contribute to the parasites' survival in the circulation of the human host.
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Affiliation(s)
- Marta C. Nunes
- Unité de Biologie des Interactions Hôte-Parasite, CNRS UR2581-Institut Pasteur, Paris, France
- * E-mail: (AS); (MCN)
| | - Mami Okada
- Unité de Biologie des Interactions Hôte-Parasite, CNRS UR2581-Institut Pasteur, Paris, France
| | | | - Brian M. Cooke
- Department of Microbiology, Monash University, Victoria, Australia
| | - Artur Scherf
- Unité de Biologie des Interactions Hôte-Parasite, CNRS UR2581-Institut Pasteur, Paris, France
- * E-mail: (AS); (MCN)
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Mulyani S, Egel E, Kittel C, Turkanovic S, Wohlleben W, Süssmuth RD, van Pée KH. The thioesterase Bhp is involved in the formation of beta-hydroxytyrosine during balhimycin biosynthesis in Amycolatopsis balhimycina. Chembiochem 2010; 11:266-71. [PMID: 19998400 DOI: 10.1002/cbic.200900600] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The putative hydrolase gene bhp from the balhimycin biosynthetic gene cluster has been cloned and overexpressed in Escherichia coli. The corresponding enzyme Bhp was purified to homogeneity by nickel-chelating chromatography and characterized. Although Bhp has sequence similarities to hydrolases with "haloperoxidase"/perhydrolase activity, it did not show any enzymatic activity with standard "haloperoxidase"/perhydrolase substrates (e.g., monochlorodimedone and phenol red), nonspecific esterase substrates (such as p-nitrophenyl acetate, p-nitrophenyl phosphate and S-thiophenyl acetate) or the model lactonase substrate dihydrocoumarin. However, Bhp could be shown to catalyse the hydrolysis of S-beta-hydroxytyrosyl-N-acetyl cysteamine thioester (beta-OH-Tyr-SNAC) with 15 times the efficiency of S-L-tyrosyl-N-acetyl cysteamine thioester (L-Tyr-SNAC). This is in agreement with the suggestion that Bhp is involved in balhimycin biosynthesis, during which it was supposed to catalyse the hydrolysis of beta-OH-Tyr-S-PCP (PCP=peptidyl carrier protein) to free beta-hydroxytyrosine (beta-OH-Tyr) and strongly suggests that Bhp is a thioesterase with high substrate specificity for PCP-bound beta-OH-Tyr and not a "haloperoxidase"/perhydrolase or nonspecific esterase.
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Affiliation(s)
- Sri Mulyani
- Biochemistry, TU Dresden, 01062 Dresden, Germany
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