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Solozabal N, Tapia L, Solà J, Pérez Y, Alfonso I. Molecular Recognition of Tyrosine-Containing Polypeptides with Pseudopeptidic Cages Unraveled by Fluorescence and NMR Spectroscopies. Bioconjug Chem 2023; 34:2345-2357. [PMID: 38078839 PMCID: PMC10859922 DOI: 10.1021/acs.bioconjchem.3c00455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/18/2023] [Accepted: 11/20/2023] [Indexed: 12/21/2023]
Abstract
The molecular recognition of Tyr-containing peptide copolymers with pseudopeptidic cages has been studied using a combination of fluorescence and NMR spectroscopies. Fluorescence titrations rendered a reasonable estimation of the affinities, despite the presence of dynamic quenching masking the unambiguous detection of the supramolecular complexes. Regarding NMR, the effect of polypeptide (PP) binding on relaxation and diffusion parameters of the cages is much more reliable than the corresponding chemical shift perturbations. To that, purification of the commercial PPs is mandatory to obtain biopolymers with lower polydispersity. Thus, the relaxation/diffusion-filtered 1H spectra of the cages in the absence vs presence of the PPs represent a suitable setup for the fast detection of the noncovalent interactions. Additional key intermolecular NOE cross-peaks supported by molecular models allow the proposal of a structure of the supramolecular species, stabilized by the Tyr encapsulation within the cage cavity and additional attractive polar interactions between the side chains of cage and PP, thus defining a binding epitope with a potential for implementing sequence selectivity. Accordingly, the cages bearing positive/negative residues prefer to bind the peptides having complementary negative/positive side chains close to the target Tyr, suggesting an electrostatic contribution to the interaction. Overall, our results show that both techniques represent a powerful and complementary combination for studying cage-to-PP molecular recognition processes.
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Affiliation(s)
- Naiara Solozabal
- NMR
Facility, Institute for Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
| | - Lucía Tapia
- Department
of Biological Chemistry, Institute for Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
| | - Jordi Solà
- Department
of Biological Chemistry, Institute for Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
| | - Yolanda Pérez
- NMR
Facility, Institute for Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
| | - Ignacio Alfonso
- Department
of Biological Chemistry, Institute for Advanced Chemistry of Catalonia, IQAC-CSIC, Jordi Girona 18-26, Barcelona 08034, Spain
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Liu YS, Chang YC, Kuo WW, Chen MC, Wang TF, Chen TS, Lin YM, Li CC, Liao PH, Huang CY. Calreticulin nuclear translocalization alleviates CaM/CaMKII/CREB signaling pathway to enhance chemosensitivity in HDAC inhibitor-resistant hepatocellular carcinoma cells. Aging (Albany NY) 2022; 14:5097-5115. [PMID: 35724265 PMCID: PMC9271289 DOI: 10.18632/aging.204131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 05/23/2022] [Indexed: 12/18/2022]
Abstract
Calreticulin (CRT) is located in the endoplasmic reticulum (ER), it helps proteins fold correctly inside the ER, and acts as a modulator of Ca2+ homeostasis. Aberrant expression of CRT is implicated in several cancer types, qualifying CRT as a potential therapeutic target. However, it remains unclear how CRT affects specific oncogenic pathways. In this study, we used histone deacetylase inhibitors (HDACis) to establish drug-resistant liver cancer cells and further analyzed the molecular mechanism of development of drug resistance in those cells. The 2D gel electrophoresis and RT-PCR data showed that CRT was downregulated in HDACis-resistant cells by comparing with HA22T parental cells. We previously elucidated the development of drug-resistance in HCC cells via activation of PP1-eIF2α pathway, but not via ER stress pathway. Here, we show that thapsigargin induced ER stress through mechanism other than ER stress downstream protein GRP78-PERK to regulate CRT expression in HDACis-R cells. Moreover, the expression level of CRT was not the main cause of apoptosis in HDACis-resistant cells. Mechanistic studies identified the apoptosis factors in the nucleus-the HDACis-mediated overexpression of CRT, CRT translocation to the cell nucleus, and reduced CaM/CaMKII/CREB pathway-that led to chemosensitivity in HDACis-R HCC cells.
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Affiliation(s)
- Yi-Sheng Liu
- Division of Hematology and Oncology, Department of Medicine, Kaohsiung Armed Forces General Hospital, Kaohsiung 802, Taiwan
- School of Medicine, National Defense Medical Center, Taipei 114, Taiwan
| | - Yu-Chun Chang
- Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan
- Department of Biological Science and Technology, College of Life Sciences, China Medical University, Taichung 406, Taiwan
| | - Wei-Wen Kuo
- Department of Biological Science and Technology, College of Life Sciences, China Medical University, Taichung 406, Taiwan
- Ph.D. Program for Biotechnology Industry, China Medical University, Taichung 406, Taiwan
| | - Ming-Cheng Chen
- Department of Surgery, Division of Colorectal Surgery, Taichung Veterans General Hospital, Taichung 407, Taiwan
- Faculty of Medicine, National Yang-Ming University, Taipei 112, Taiwan
| | - Tso-Fu Wang
- Department of Hematology and Oncology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, School of Medicine Tzu Chi University, Hualien 97004, Taiwan
| | - Tung-Sheng Chen
- School of Life Science, National Taiwan Normal University, Taipei 116, Taiwan
| | - Yueh-Min Lin
- School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan
- Department of Surgical Pathology, Changhua Christian Hospital, Changhua 500, Taiwan
| | - Chi-Cheng Li
- Center of Stem Cell and Precision Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan
| | - Po-Hsiang Liao
- Division of General Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City 235, Taiwan
| | - Chih-Yang Huang
- Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 404, Taiwan
- Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung 413, Taiwan
- Center of General Education, Buddhist Tzu Chi Medical Foundation, Tzu Chi University of Science and Technology, Hualien 970, Taiwan
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Alavi Naini SM, Soussi-Yanicostas N. Heparan Sulfate as a Therapeutic Target in Tauopathies: Insights From Zebrafish. Front Cell Dev Biol 2018; 6:163. [PMID: 30619849 PMCID: PMC6306439 DOI: 10.3389/fcell.2018.00163] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/15/2018] [Indexed: 12/13/2022] Open
Abstract
Microtubule-associated protein tau (MAPT) hyperphosphorylation and aggregation, are two hallmarks of a family of neurodegenerative disorders collectively referred to as tauopathies. In many tauopathies, including Alzheimer's disease (AD), progressive supranuclear palsy (PSP) and Pick's disease, tau aggregates are found associated with highly sulfated polysaccharides known as heparan sulfates (HSs). In AD, amyloid beta (Aβ) peptide aggregates associated with HS are also characteristic of disease. Heparin, an HS analog, promotes misfolding, hyperphosphorylation and aggregation of tau protein in vitro. HS also provides cell surface receptors for attachment and uptake of tau seeds, enabling their propagation. These findings point to HS-tau interactions as potential therapeutic targets in tauopathies. The zebrafish genome contains genes paralogous to MAPT, genes orthologous to HS biosynthetic and chain modifier enzymes, and other genes implicated in AD. The nervous system in the zebrafish bears anatomical and chemical similarities to that in humans. These homologies, together with numerous technical advantages, make zebrafish a valuable model for investigating basic mechanisms in tauopathies and identifying therapeutic targets. Here, we comprehensively review current knowledge on the role of HSs in tau pathology and HS-targeting therapeutic approaches. We also discuss novel insights from zebrafish suggesting a role for HS 3-O-sulfated motifs in tau pathology and establishing HS antagonists as potential preventive agents or therapies for tauopathies.
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Affiliation(s)
- Seyedeh Maryam Alavi Naini
- Department of Neuroscience, Institut de Biologie Paris Seine (IBPS), INSERM, CNRS, Sorbonne Université, Paris, France
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4
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Anguita E, Villalobo A. Src-family tyrosine kinases and the Ca 2+ signal. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:915-932. [PMID: 27818271 DOI: 10.1016/j.bbamcr.2016.10.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/25/2016] [Accepted: 10/30/2016] [Indexed: 01/08/2023]
Abstract
In this review, we shall describe the rich crosstalk between non-receptor Src-family kinases (SFKs) and the Ca2+ transient generated in activated cells by a variety of extracellular and intracellular stimuli, resulting in diverse signaling events. The exchange of information between SFKs and Ca2+ is reciprocal, as it flows in both directions. These kinases are main actors in pathways leading to the generation of the Ca2+ signal, and reciprocally, the Ca2+ signal modulates SFKs activity and functions. We will cover how SFKs participate in the generation of the cytosolic Ca2+ rise upon activation of a series of receptors and the mechanism of clearance of this Ca2+ signal. The role of SFKs modulating Ca2+-translocating channels participating in these events will be amply discussed. Finally, the role of the Ca2+ sensor protein calmodulin on the activity of c-Src, and potentially on other SFKs, will be outlined as well. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Estefanía Anguita
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/ Arturo Duperier 4, E-28029 Madrid, Spain
| | - Antonio Villalobo
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/ Arturo Duperier 4, E-28029 Madrid, Spain.
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Chen HJ, Jiang YL, Lin CM, Tsai SC, Peng SF, Fushiya S, Hour MJ, Yang JS. Dual inhibition of EGFR and c-Met kinase activation by MJ-56 reduces metastasis of HT29 human colorectal cancer cells. Int J Oncol 2013; 43:141-50. [PMID: 23677180 DOI: 10.3892/ijo.2013.1941] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 04/09/2013] [Indexed: 11/05/2022] Open
Abstract
Quinazolinone derivatives are known to possess anticancer activities on cell metastasis and cell death in different human cancer cell lines. Here, we studied the anti-metastasis activity and the underlying mechanisms of the novel quinazoline derivative MJ-56 (6-pyrrolidinyl-2-(3-bromostyryl)quinazolin-4-one). MJ-56 inhibited cell migration and invasion of HT29 human colorectal cancer cells by wound-healing and Matrigel-coated transwell assays in a concentration-dependent manner. MJ-56-treated cells resulted in the reduced expression of matrix metalloproteinase (MMP)-2, -7, -9 and -10 and the reduced enzymatic activities of MMP-2 and MMP-9. In contrast, MJ-56-treated cells enhanced the expression of the tissue inhibitors of metalloproteinases (TIMPs) TIMP-1 and TIMP-2. Further analyses showed that MJ-56 attenuated the activities of epidermal growth factor receptor (EGFR), c-Met and the downstream ERK-mediated MAPK and PI3K/AKT/mTOR signaling pathways, which led to decreased protein synthesis by dephosphorylating the translation initiation factors eIF-4B, eIF-4E, eIF-4G and S6 ribosomal protein. In addition, MJ-56 interfered with the NF-κB signaling via impairing PI3K/AKT activation and subsequently reduced the NF-κB-mediated transcription of MMPs. Taken together, the reduced expression of phosphor-EGFR and c-MET is chiefly responsible for all events of blocking metastasis. Our results suggest a potential role of MJ-56 on therapy of colorectal cancer metastasis.
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Affiliation(s)
- Hui-Jye Chen
- Graduate Institute of Molecular Systems Biomedicine, China Medical University, Taichung 404, Taiwan, R.O.C
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Abstract
Biomechanical signals such as cell shape and spreading play an important role in controlling stem cell commitment. Cell shape, adhesion and spreading are also affected by calreticulin, a multifunctional calcium-binding protein, which influences several cellular processes, including adipogenesis. Here we show that cytoskeletal disruption in mouse embryonic stem cells using cytochalasin D or nocodazole promotes adipogenesis. While cytochalasin D disrupts stress fibres and inhibits focal adhesion formation, nocodazole depolymerises microtubules and promotes focal adhesion formation. Furthermore, cytochalasin D increases the levels of both total and activated calcium/calmodulin-dependent protein kinase II, whereas nocodazole decreases it. Nevertheless, both treatments significantly increase the adipogenic potential of embryonic stem cells in vitro. Both cytochalasin D and nocodazole exposure caused cell rounding suggesting that it is cell shape that causes the switch towards the adipogenic programme. Calreticulin-containing embryonic stem cells, under baseline conditions, show low adipogenic potential, have low activity of signalling via calcium/calmodulin-dependent protein kinase II and display normal adhesive properties and cellular spreading in comparison to the highly adipogenic but poorly spread calreticulin-deficient ES cells. We conclude that forced cell rounding via cytoskeletal disruption overrides the effects of calreticulin, an ER chaperone, thus negatively regulating adipogenesis via focal adhesion-mediated cell spreading.
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Szabo E, Qiu Y, Baksh S, Michalak M, Opas M. Calreticulin inhibits commitment to adipocyte differentiation. ACTA ACUST UNITED AC 2008; 182:103-16. [PMID: 18606846 PMCID: PMC2447897 DOI: 10.1083/jcb.200712078] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Calreticulin, an endoplasmic reticulum (ER) resident protein, affects many critical cellular functions, including protein folding and calcium homeostasis. Using embryonic stem cells and 3T3-L1 preadipocytes, we show that calreticulin modulates adipogenesis. We find that calreticulin-deficient cells show increased potency for adipogenesis when compared with wild-type or calreticulin-overexpressing cells. In the highly adipogenic crt−/− cells, the ER lumenal calcium concentration was reduced. Increasing the ER lumenal calcium concentration led to a decrease in adipogenesis. In calreticulin-deficient cells, the calmodulin–Ca2+/calmodulin-dependent protein kinase II (CaMKII) pathway was up-regulated, and inhibition of CaMKII reduced adipogenesis. Calreticulin inhibits adipogenesis via a negative feedback mechanism whereby the expression of calreticulin is initially up-regulated by peroxisome proliferator–activated receptor γ (PPARγ). This abundance of calreticulin subsequently negatively regulates the expression of PPARγ, lipoprotein lipase, CCAAT enhancer–binding protein α, and aP2. Thus, calreticulin appears to function as a Ca2+-dependent molecular switch that regulates commitment to adipocyte differentiation by preventing the expression and transcriptional activation of critical proadipogenic transcription factors.
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Affiliation(s)
- Eva Szabo
- Department of Laboratory Medicine and Pathobiology, Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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8
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Papp S, Szabo E, Kim H, McCulloch CA, Opas M. Kinase-dependent adhesion to fibronectin: Regulation by calreticulin. Exp Cell Res 2008; 314:1313-26. [DOI: 10.1016/j.yexcr.2008.01.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 12/11/2007] [Accepted: 01/07/2008] [Indexed: 11/17/2022]
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9
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Szabo E, Papp S, Opas M. Differential calreticulin expression affects focal contacts via the calmodulin/CaMK II pathway. J Cell Physiol 2007; 213:269-77. [PMID: 17516550 DOI: 10.1002/jcp.21122] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Calreticulin is an ER calcium-storage protein, which influences gene expression and cell adhesion. In this study, we analysed the differences in adhesive properties of calreticulin under- and overexpressing fibroblasts in relation to the calmodulin- and calcium/calmodulin-dependent kinase II (CaMK II)-dependent signalling pathways. Cells stably underexpressing calreticulin had elevated expression of calmodulin, activated CaMK II, activated ERK and activated c-src. Inhibition of calmodulin by W7, and CaMK II by KN-62, caused the otherwise weekly adhesive calreticulin underexpressing cells to behave like the overexpressing cells, via induction of increased cell spreading. Increased vinculin, activated paxillin, activated focal adhesion kinase and fibronectin levels were observed upon inhibition of either the calmodulin or the CaMK II signalling pathways, which was accompanied by an increase in cell spreading and focal contact formation. Both KN-62 and W7 treatment increased cell motility in underexpressing cells, but W7 treatment led to loss of directionality. Thus, both the calmodulin and CaMK II signalling pathways influence cellular spreading and motility, but subtle differences exist in their distal effects on motility effectors.
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Affiliation(s)
- Eva Szabo
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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10
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Batenjany M, Bartnicki D, Ambuel Y, Wiepz G, Bertics P, Hayes S. Rapid, ELISA-based measurement of protein tyrosine kinase activity using the K-LISA™ Kit. Nat Methods 2005. [DOI: 10.1038/nmeth788] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Dziewanowska K, Carson AR, Patti JM, Deobald CF, Bayles KW, Bohach GA. Staphylococcal fibronectin binding protein interacts with heat shock protein 60 and integrins: role in internalization by epithelial cells. Infect Immun 2000; 68:6321-8. [PMID: 11035741 PMCID: PMC97715 DOI: 10.1128/iai.68.11.6321-6328.2000] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We reported previously that internalization of Staphylococcus aureus by nonprofessional phagocytes involves an interaction between fibronectin (Fn) binding protein (FnBP) and the host cell, resulting in signal transduction, tyrosine kinase activity, and cytoskeletal rearrangement (K. Dziewanowska, J. M. Patti, C. F. Deobald, K. W. Bayles, W. R. Trumble, and G. A. Bohach, Infect. Immun. 67:4673-4678, 1999). The goal of the present study was to identify the host molecules responsible for uptake of the organism through an interaction with FnBP. First, Fn was required for internalization. Addition of small amounts of exogenous Fn stimulated the uptake of S. aureus by HEp-2 cells, which are deficient in Fn synthesis. Fn antibodies blocked internalization of the organism by MAC-T cell monolayers, a bovine epithelial cell line which expresses Fn. Second, a monoclonal antibody (MAb) specific for beta(1) integrins dramatically reduced S. aureus invasion, suggesting that the formation of a Fn bridge linking the host cell beta(1) integrin and FnBP precedes internalization. However, ligand blotting of cell membrane proteins with a functional fragment of FnBP consistently identified an additional approximately 55-kDa receptor on both human and bovine epithelial cells. This protein was purified and identified by N-terminal microsequencing as heat shock protein 60 (Hsp60). The interaction between FnBP and Hsp60 also occurred when the whole cells were used. Cell membrane localization of Hsp60 was confirmed by biotinylation with an agent nonpermeable to the cell membrane. Pretreatment of epithelial cells with a MAb specific for eukaryotic Hsp60 significantly reduced internalization of S. aureus. Combined, these results suggest that the FnBP binds directly to both Hsp60 and Fn and is linked to beta(1) integrins through a Fn bridge. The simultaneous involvement of Fn and two host cell ligands, beta(1) integrins and Hsp60, suggests that FnBP is a multifunctional adhesin that mediates internalization in a manner similar to that proposed for OpaA, the Neisseria gonorrhoeae FnBP homolog (J. P. M. van Putten, T. D. Duensing, and R. L. Cole, Mol. Microbiol. 29:369-379, 1998).
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Affiliation(s)
- K Dziewanowska
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844, USA
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12
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Khan IU, Wallin R, Gupta RS, Kammer GM. Protein kinase A-catalyzed phosphorylation of heat shock protein 60 chaperone regulates its attachment to histone 2B in the T lymphocyte plasma membrane. Proc Natl Acad Sci U S A 1998; 95:10425-30. [PMID: 9724719 PMCID: PMC27910 DOI: 10.1073/pnas.95.18.10425] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/1998] [Accepted: 06/26/1998] [Indexed: 11/18/2022] Open
Abstract
Accumulating evidence suggests that the mitochondrial molecular chaperone heat shock protein 60 (hsp60) also can localize in extramitochondrial sites. However, direct evidence that hsp60 functions as a chaperone outside of mitochondria is presently lacking. A 60-kDa protein that is present in the plasma membrane of a human leukemic CD4(+) CEM-SS T cell line and is phosphorylated by protein kinase A (PKA) was identified as hsp60. An 18-kDa plasma membrane-associated protein coimmunoprecipitated with hsp60 and was identified as histone 2B (H2B). Hsp60 physically associated with H2B when both molecules were in their dephospho forms. By contrast, PKA-catalyzed phosphorylation of both hsp60 and H2B caused dissociation of H2B from hsp60 and loss of H2B from the plasma membrane of intact T cells. These results suggest that (i) hsp60 and H2B can localize in the T cell plasma membrane; (ii) hsp60 functions as a molecular chaperone for H2B; and (iii) PKA-catalyzed phosphorylation of both hsp60 and H2B appears to regulate the attachment of H2B to hsp60. We propose a model in which phosphorylation/dephosphorylation regulates chaperoning of H2B by hsp60 in the plasma membrane.
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Affiliation(s)
- I U Khan
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, N. C. 27157, Canada
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13
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Xu B, Miller WT. Src homology domains of v-Src stabilize an active conformation of the tyrosine kinase catalytic domain. Mol Cell Biochem 1996; 158:57-63. [PMID: 8791285 DOI: 10.1007/bf00225883] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To examine the interactions between Src homology domains and the tyrosine kinase catalytic domain of v-Src, various combinations of domains have been expressed in bacteria as fusion proteins. Constructs containing the isolated catalytic domain, SH2 + catalytic domain, and SH3 + SH2 + catalytic domains were active in autophosphorylation assays. For the catalytic domain of v-Src, but not for v-Abl, addition of exogenous Src SH3-SH2 domains stimulated the autophosphorylation activity. In contrast to results for autophosphorylation, constructs containing Src homology domains were more active towards a synthetic peptide substrate than the isolated catalytic domain. The ability of the SH2 and SH3 domains of v-Src to stabilize an active enzyme conformation was also confirmed by refolding after denaturation in guanidinium hydrochloride. Collectively the data suggest that, in addition to their roles in intermolecular protein-protein interactions, the Src homology regions of v-Src exert a positive influence on tyrosine kinase function, potentially by maintaining an active conformation of the catalytic domain.
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Affiliation(s)
- B Xu
- Department of Physiology and Biophysics, School of Medicine, State University of New York at Stony Brook 11794, USA
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14
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Borowski P, Heiland M, Oehlmann K, Becker B, Kornetzky L, Feucht H, Laufs R. Non-structural protein 3 of hepatitis C virus inhibits phosphorylation mediated by cAMP-dependent protein kinase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 237:611-8. [PMID: 8647104 DOI: 10.1111/j.1432-1033.1996.0611p.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Inspection of the amino acid sequence of the non-structural region of the hepatitis C virus (HCV) gene product reveals a sequence of 14 amino acids, Arg1487-Arg-Gly-Arg-Thr-Gly-Arg-Gly-Arg-Arg-Gly-Ile-Tyr-Arg1500 , located in the non-structural protein, NS3. This sequence is highly similar to the inhibitory site of the heat-stable inhibitor of cAMP-dependent protein kinase (PKA) and to the autophosphorylation site in the hinge region of the PKA type II regulatory domain. A synthetic peptide that corresponds to the HCV sequence above and a set of shorter analogues act as competitive inhibitors of PKA. A 43.5-kDa fragment of NS3 that consists of residues 1189-1525 of the HCV polyprotein inhibits PKA in a similar range to the investigated synthetic peptides. In contrast to the short peptides, which show competitive inhibition, HCV-polyprotein-(1189-1525) influences PKA in a mixed-inhibition-type manner. A possible mechanism explaining these differences is the formation of complexes that consist of the protein substrate, the enzyme and the HCV-polyprotein-(1189-1525). Binding studies with PKA and the non-hydrolysable ATP analogue [14C]fluorosulfonylbenzoyladenosine and [3H]cAMP do not reveal any influence of the short HCV-derived peptides or HCV-polyprotein-(1189-1525) upon the affinity of PKA for these nucleotides. The complex interactions of the NS3 fragments could influence one of the most important signal pathways of the cell and, therefore, could possibly provide new pathological mechanisms for HCV infections of liver.
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Affiliation(s)
- P Borowski
- Institut für Medizinische Mikrobiologie und Immunologie, Universitätskrankenhaus Eppendorf, Hamburg, Germany
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15
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Chang CM, Shu HK, Kung HJ. Disease specificity of kinase domains: the src-encoded catalytic domain converts erbB into a sarcoma oncogene. Proc Natl Acad Sci U S A 1995; 92:3928-32. [PMID: 7732007 PMCID: PMC42075 DOI: 10.1073/pnas.92.9.3928] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
src and erbB are two tyrosine kinase-encoding oncogenes carried by retroviruses, which have distinct disease specificities. The former induces predominantly sarcomas, and the latter, leukemias. Src and ErbB have similar catalytic domains but have very different regulatory domains. A wealth of information exists concerning how different regulatory domains [Src homology 2 (SH2) and SH3 domains and autophosphorylation sites] control substrate and disease specificities. Whether the catalytic domain helps determine these specificities remains to be explored. Here we show that the Src catalytic domain is enzymatically active when substituted into the ErbB backbone and interacts with the ErbB regulatory domain. This ErbB/Src chimera displays autophosphorylation and substrate phosphorylation patterns different from those of both Src and ErbB. Neither SH2 and SH3 nor autophosphorylation sites are required for the Src catalytic domain to exert its fibroblast transforming ability. Most significantly, the catalytic domain can convert erbB from a leukemogenic oncogene into a sarcomagenic oncogene, suggesting that the leukemogenic determinants in part reside within the ErbB catalytic domain.
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Affiliation(s)
- C M Chang
- Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
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16
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Ruzzene M, James P, Brunati A, Donella-Deana A, Pinna L. Regulation of c-Fgr protein kinase by c-Src kinase (CSK) and by polycationic effectors. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)40763-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Differential effect of phosphorylation and substrate modulation on tau's ability to promote microtubule growth and nucleation. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32639-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Jones M, Gupta RS, Englesberg E. Enhancement in amount of P1 (hsp60) in mutants of Chinese hamster ovary (CHO-K1) cells exhibiting increases in the A system of amino acid transport. Proc Natl Acad Sci U S A 1994; 91:858-62. [PMID: 7905632 PMCID: PMC521411 DOI: 10.1073/pnas.91.3.858] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mutants of CHO-K1 cells with varied levels of A system activity, probably the result of increases in absolute amount of the A system transporter, have corresponding increases in levels of peptides banding at 62-66 and 29 kDa. Mutant alar4-H3.9, showing the highest increase of A system activity and of 62- to 66- and 29-kDa peptides, was selected for this study. The N terminus 16-amino acid sequence of the 62- to 66-kDa peptide(s) of this mutant showed between 80% and 100% identity with the mammalian mitochondrial 60-kDa heat shock protein P1 (hsp60). Two-dimensional gel electrophoresis of the 62- to 66-kDa band showed two major, a minor, and several smaller spots (of same mass but different pI values) for both wild type (WT) and mutant, with the two major spots being of greater density in the mutant. Immunoblots with antibody to P1 identified the two major and minor peptides as P1 related. Two-dimensional gels of whole cell extracts of the WT and alar4-H3.9 confirmed these findings and indicated that the two major bands of the mutant were 2.4 times as abundant as that found for the WT. A plasma membrane fraction of the mutant, exhibiting 4.8 times more A system activity than the WT, contained 3.6 times as much P1 as the WT. Immunoblots with antibodies to P1, mitochondrial malate dehydrogenase, and to the mitochondrial F1/F0-ATPase demonstrated that the increased amount of P1 observed in the mutant was not the result of increases in amount of mitochondrial protein. Northern blot analysis demonstrated that the mutant had 2.5 times as much mRNA for P1 as the WT. The close analogy with the relationship between A system and Na+,K(+)-ATPase suggests that there is a coordinate regulation of the A system of amino acid transport, Na+,K(+)-ATPase, and P1 protein, probably as a result of mutation in a shared regulatory element. The possible role of P1 in A system function is discussed.
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Affiliation(s)
- M Jones
- University of California, Santa Barbara 93106
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Budde RJ, Ramdas L, Ke S. Recombinant pp60c-src from baculovirus-infected insect cells: purification and characterization. PREPARATIVE BIOCHEMISTRY 1993; 23:493-515. [PMID: 7504254 DOI: 10.1080/10826069308544572] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A simple and effective method has been developed to purify the recombinant protein tyrosine kinase pp60c-src from a baculovirus-insect cell expression system. The procedure includes affinity chromatography and HPLC. Milligram quantities of protein have been isolated with an activity of 3.9 mumol/min/mg protein using the substrate poly E4Y. This specific activity is many times higher than any published protocol. The enzyme is stable for months when stored in buffered 10% glycerol at -70 degrees C. This purification technique is compared to the immuno-affinity technique which is widely used for this enzyme. Enzyme kinetics were characterized with respect to substrate specificity, the effect of temperature, ionic strength, pH, and Mg+2 versus Mn+2 ions. Similar to the enzyme expressed in human cells, the recombinant enzyme demonstrated a higher Vmax and substrate specificity for poly E4Y over 5V-Agt-II. An activation energy of 14.2 kcal/mol was determined. Inhibition by increasing ionic strength is mostly due to an increase in Km for the poly E4Y substrate and hence was substrate dependent. The Km(ATP) was pH dependent while the Km(poly E4Y) was pH independent. For the phosphorylation of poly E4Y, free Mg+2 was stimulatory while Mn+2 was inhibitory. In contrast, Mn+2 stimulated the phosphorylation of 5V-Agt-II.
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Affiliation(s)
- R J Budde
- Department of Neuro-Oncology, University of Texas, M.D. Anderson Cancer Center, Houston 77030
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Mawal-Dewan M, Sen P, Abdel-Ghany M, Shalloway D, Racker E. Phosphorylation of tau protein by purified p34cdc28 and a related protein kinase from neurofilaments. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41832-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Racker E. Chaperones and matchmakers: inhibitors and stimulators of protein phosphorylation. CURRENT TOPICS IN CELLULAR REGULATION 1992; 33:127-43. [PMID: 1354148 DOI: 10.1016/b978-0-12-152833-1.50013-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- E Racker
- Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853
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Revis-Gupta S, Abdel-Ghany M, Koland J, Racker E. Heparin stimulates epidermal growth factor receptor-mediated phosphorylation of tyrosine and threonine residues. Proc Natl Acad Sci U S A 1991; 88:5954-8. [PMID: 1712476 PMCID: PMC52000 DOI: 10.1073/pnas.88.14.5954] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have described previously that in extracts of A431 cells epidermal growth factor (EGF) stimulates the phosphorylation of tyrosine as well as of threonine residues in the EGF receptor and in lipocortin 1. We now report that heparin at low concentrations also stimulates the autophosphorylation of the EGF receptor and of the recombinant 56-kDa domain of the EGF receptor that lacks the EGF binding site. To study the stimulations of phosphorylation of threonine residues, a fusion protein was prepared with glutathione S-transferase (GST) and an EGF receptor fragment, TK8 (residues 647-688), that contains the threonine phosphorylation site but no tyrosine. We show that the phosphorylation of threonine residues in GST-TK8 by extracts of A431 cells is stimulated by heparin but not by EGF. These and other results suggest that heparin acts as a chaperone, a substrate modulator, that enhances the susceptibility of the substrate to phosphorylation by protein kinases.
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Affiliation(s)
- S Revis-Gupta
- Section of Biochemistry, Molecular and Cell Biology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853
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Affiliation(s)
- D Shalloway
- Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802
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