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Meloni BP, Mastaglia FL, Knuckey NW. Cationic Arginine-Rich Peptides (CARPs): A Novel Class of Neuroprotective Agents With a Multimodal Mechanism of Action. Front Neurol 2020; 11:108. [PMID: 32158425 PMCID: PMC7052017 DOI: 10.3389/fneur.2020.00108] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/30/2020] [Indexed: 12/17/2022] Open
Abstract
There are virtually no clinically available neuroprotective drugs for the treatment of acute and chronic neurological disorders, hence there is an urgent need for the development of new neuroprotective molecules. Cationic arginine-rich peptides (CARPs) are an expanding and relatively novel class of compounds, which possess intrinsic neuroprotective properties. Intriguingly, CARPs possess a combination of biological properties unprecedented for a neuroprotective agent including the ability to traverse cell membranes and enter the CNS, antagonize calcium influx, target mitochondria, stabilize proteins, inhibit proteolytic enzymes, induce pro-survival signaling, scavenge toxic molecules, and reduce oxidative stress as well as, having a range of anti-inflammatory, analgesic, anti-microbial, and anti-cancer actions. CARPs have also been used as carrier molecules for the delivery of other putative neuroprotective agents across the blood-brain barrier and blood-spinal cord barrier. However, there is increasing evidence that the neuroprotective efficacy of many, if not all these other agents delivered using a cationic arginine-rich cell-penetrating peptide (CCPPs) carrier (e.g., TAT) may actually be mediated largely by the properties of the carrier molecule, with overall efficacy further enhanced according to the amino acid composition of the cargo peptide, in particular its arginine content. Therefore, in reviewing the neuroprotective mechanisms of action of CARPs we also consider studies using CCPPs fused to a putative neuroprotective peptide. We review the history of CARPs in neuroprotection and discuss in detail the intrinsic biological properties that may contribute to their cytoprotective effects and their usefulness as a broad-acting class of neuroprotective drugs.
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Affiliation(s)
- Bruno P Meloni
- Department of Neurosurgery, QEII Medical Centre, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Frank L Mastaglia
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Neville W Knuckey
- Department of Neurosurgery, QEII Medical Centre, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
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Protamine stimulates bone sialoprotein gene expression. Gene 2013; 516:228-37. [DOI: 10.1016/j.gene.2012.12.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 12/02/2012] [Indexed: 01/19/2023]
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Sobolev AS. Modular nanotransporters of anticancer drugs conferring cell specificity and higher efficiency. BIOCHEMISTRY (MOSCOW) 2010; 74:1567-74. [PMID: 20210709 DOI: 10.1134/s0006297909130094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This review deals with artificial modular nanotransporters (MNT) of polypeptide nature for drug delivery into target cells and then into a specified cell compartment like the nucleus. The developed approach is based on the use of intracellular transport processes characteristic of practically all cells, including cancer cells. The first MNT module ligand carries out a double function: specific recognition of a cancer target cell and penetration into the cell via receptor-mediated endocytosis. The movement of the MNT within the cell along this path specifies the need to supply the MNT with an endosomolytic module making it possible to leave the endocytotic pathway before getting into lysosomes in order to have time for interaction with importins. For this purpose, a polypeptide fragment able to make defects in membranes only at the pH of endosomes is used as the second module. Delivery into the cell nucleus is provided by the third module containing an amino acid sequence of nuclear localization, "recognized" by importins located in the hyaloplasm. And finally, the fourth module, a carrier for joining the transported drug, is incorporated into the MNT. Depending on the type of ligand module, MNT for different target cell types have been produced. Each module retains its activity within the MNT, ligand modules bind target receptors with high affinity, while the module with the nuclear localization sequence binds importins. The endosomolytic module forms pores in lipid membranes through which MNT are able to leave acidifying cell compartments (endosomes). Modules within MNT can be replaced or transposed, which makes it possible to use them for delivery of different drugs into different target cells and their compartments. It was shown that photosensitizers and radionuclides used for cancer therapy acquire pronounced cell specificity as well as the 10-1000-fold higher efficiency resulting from their delivery into the most vulnerable compartment--the cell nucleus.
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Affiliation(s)
- A S Sobolev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.
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Liu KX, Kato Y, Matsumoto K, Nakamura T, Kaku T, Sugiyama Y. Characterization of the Enhancing Effect of Protamine on the Proliferative Activity of Hepatocyte Growth Factor in Rat Hepatocytes. Pharm Res 2009; 26:1012-21. [DOI: 10.1007/s11095-008-9810-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Accepted: 12/11/2008] [Indexed: 10/21/2022]
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Sobolev AS. Modular transporters for subcellular cell-specific targeting of anti-tumor drugs. Bioessays 2008; 30:278-87. [DOI: 10.1002/bies.20715] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Gilyazova DG, Rosenkranz AA, Gulak PV, Lunin VG, Sergienko OV, Khramtsov YV, Timofeyev KN, Grin MA, Mironov AF, Rubin AB, Georgiev GP, Sobolev AS. Targeting Cancer Cells by Novel Engineered Modular Transporters. Cancer Res 2006; 66:10534-40. [PMID: 17079476 DOI: 10.1158/0008-5472.can-06-2393] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A major problem in the treatment of cancer is the specific targeting of drugs to these abnormal cells. Ideally, such a drug should act over short distances to minimize damage to healthy cells and target subcellular compartments that have the highest sensitivity to the drug. We describe the novel approach of using modular recombinant transporters to target photosensitizers to the nucleus, where their action is most pronounced, of cancer cells overexpressing ErbB1 receptors. We have produced a new generation of the transporters consisting of (a) epidermal growth factor as the internalizable ligand module to ErbB1 receptors, (b) the optimized nuclear localization sequence of SV40 large T-antigen, (c) a translocation domain of diphtheria toxin as an endosomolytic module, and (d) the Escherichia coli hemoglobin-like protein HMP as a carrier module. The modules retained their functions within the transporter chimera: they showed high-affinity interactions with ErbB1 receptors and alpha/beta-importin dimers and formed holes in lipid bilayers at endosomal pH. A photosensitizer conjugated with the transporter produced singlet oxygen and (*)OH radicals similar to the free photosensitizer. Photosensitizers-transporter conjugates have >3,000 times greater efficacy than free photosensitizers for target cells and were not photocytotoxic at these concentrations for cells expressing a few ErbB1 receptors per cell, in contrast to free photosensitizers. The different modules of the transporters, which are highly expressed and easily purified to retain full activity of each of the modules, are interchangeable, meaning that they can be tailored for particular applications.
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Zhang L, Gjoerup O, Roberts TM. The serine/threonine kinase cyclin G-associated kinase regulates epidermal growth factor receptor signaling. Proc Natl Acad Sci U S A 2004; 101:10296-301. [PMID: 15240878 PMCID: PMC478566 DOI: 10.1073/pnas.0403175101] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cyclin G-associated kinase (GAK) is a serine/threonine kinase that features high homology outside its kinase domain with auxilin. Like auxilin, GAK has been shown to be a cofactor for uncoating clathrin vesicles in vitro. We investigated epidermal growth factor (EGF) receptor-mediated signaling in cells, in which GAK is down-regulated by small hairpin RNAs. Here, we report that down-regulation of GAK by small hairpin RNA has two pronounced effects on EGF receptor signaling: (i) the levels of receptor expression and tyrosine kinase activity go up by >50-fold; and (ii) the spectrum of downstream signaling is significantly changed. One very obvious result is a large increase in the levels of activated extracellular signal-regulated kinase 5 and Akt. These two effects of GAK down-regulation result from, at least in part, alterations in receptor trafficking, the most striking of which is the persistence of EGF receptor in altered cellular compartment along with activated extracellular signal-regulated kinase 5. The alterations resulting from GAK down-regulation can have distinctive biological consequences: In CV1P cells, down-regulation of GAK results in outgrowth of cells in soft agar, raising the possibility that loss of GAK function may promote tumorigenesis.
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Affiliation(s)
- Lei Zhang
- Department of Cancer Biology, Dana-Farber Cancer Institute, and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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Raghavarao KS, Dueser M, Todd P. Multistage magnetic and electrophoretic extraction of cells, particles and macromolecules. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2001; 68:139-90. [PMID: 11036687 DOI: 10.1007/3-540-45564-7_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Improved techniques for separating cells, particles, and macromolecules (proteins) are increasingly important to biotechnology because separation is frequently the limiting factor for many biological processes. Manufacturers of new enzymes and pharmaceutical products require improved methods for recovering intact cells and intracellular products. Similarly isolation, purification, and concentration of many biomolecules produced in fermentation processes is extremely important. Often such downstream processing contributes a large portion of the product cost. In conventional methods like centrifugation and even modern methods like chromatography, scale-up problems are enormous, making them uneconomical and prohibitively expensive unless the product is of very high value. Therefore there has been a need for efficient and economical alternative approaches to bioseparation processes to eliminate, reduce, or facilitate solids handling. Magnetic and electric field assisted separations may hold considerable potential for providing a future major improvement in bioseparation technology. In the present review the merits and demerits of the existing methods are discussed. We present mainly our own research on the development of unified multistage extraction processes that are versatile enough to handle cells and particles as well as macromolecules as described below. We describe multistage methods, namely ADSEP (Advanced Separator), MAGSEP (Magnetic Separator), and ELECSEP (Electrophoretic Separator), for quantitatively separating cells, particles, and solutes by using magnetically and electrophoretically assisted extraction processes. To the best of our knowledge, multistage magnetic and electrophoretic separations have not been reported in the earlier literature. The theoretical underpinnings of these separations are crucial to their success and to the identification of their advantages over other separation processes in particular applications. Hence mathematical modeling is stressed here, presenting our own models while also reviewing models reported in the literature. We also present suggestions for future work while analyzing the scale-up and economic aspects of these extraction processes. Commercial uses of the magnetic and electrophoretic processes, having both ground- and space-based research elements, also are presented in this review.
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Affiliation(s)
- K S Raghavarao
- Department of Food Engineering, Central Food Technological Research Institute (CFTRI), Mysore, India.
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Abstract
BACKGROUND Protamine sulphate has been reported to stimulate nitric oxide production from blood vessels, which is a pivotal factor for gastric ulcer healing. Our preliminary study also showed that protamine sulphate potentiated the ulcer healing effect of heparin. METHODS Male SD rats with acetic acid-induced gastric ulcers were given protamine sulphate (40-80 mg/kg, s.c.) twice daily for 4 or 7 days. L-NG-nitroarginine methyl ester (L-NAME, 5 mg/kg), an inhibitor of nitric oxide synthase (NOS), was given s.c. prior to protamine sulphate (80 mg/kg) treatment. Ulcer healing, angiogenesis, mucosal histological changes, NOS activity and growth factors were determined. RESULTS Protamine sulphate dose-dependently accelerated gastric ulcer healing, which was accompanied by a significant increase in angiogenesis, mucosal regeneration and constitutive NOS activity. Inhibition of gastric secretion was observed. Epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), tumour necrosis factor-alpha (TNF-alpha) or inducible NOS activity was also affected. L-NAME completely blocked the beneficial effects of protamine sulphate. CONCLUSIONS Protamine sulphate accelerates gastric ulcer healing through a mucosal nitric oxide-dependent and possibly also the EGF-and bFGF-associated pathways, which are followed by an increase of angiogenesis and mucosal regeneration. Acid inhibition contributes in part to the ulcer healing action of protamine sulphate.
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Affiliation(s)
- Y Li
- Department of Pharmacology, Faculty of Medicine, The University of Hong Kong, China
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Leal SM, Huang SS, Huang JS. Interactions of high affinity insulin-like growth factor-binding proteins with the type V transforming growth factor-beta receptor in mink lung epithelial cells. J Biol Chem 1999; 274:6711-7. [PMID: 10037769 DOI: 10.1074/jbc.274.10.6711] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
High affinity insulin-like growth factor-binding proteins (IGFBP-1 to -6) are a family of structurally homologous proteins that induce cellular responses by insulin-like growth factor (IGF)-dependent and -independent mechanisms. The IGFBP-3 receptor, which mediates the IGF-independent growth inhibitory response, has recently been identified as the type V transforming growth factor-beta receptor (TbetaR-V) (Leal, S. M., Liu, Q. L., Huang, S. S., and Huang, J. S. (1997) J. Biol. Chem. 272, 20572-20576). To characterize the interactions of high affinity IGFBPs with TbetaR-V, mink lung epithelial cells (Mv1Lu cells) were incubated with 125I-labeled recombinant human IGFBPs (125I-IGFBP-1 to -6) in the presence of the cross-linking agent disuccinimidyl suberate and analyzed by 5% SDS-polyacrylamide gel electrophoresis and autoradiography. 125I-IGFBP-3, -4, and -5 but not 125I-IGFBP-1, -2, and -6 bound to TbetaR-V as demonstrated by the detection of the approximately 400-kDa 125I-IGFBP.TbetaR-V cross-linked complex in the cell lysates and immunoprecipitates. The analyses of 125I-labeled ligand binding competition and DNA synthesis inhibition revealed that IGFBP-3 was a more potent ligand for TbetaR-V than IGFBP-4 or -5. Most of the high affinity 125I-IGFBPs formed dimers at the cell surface. The cell-surface dimer of 125I-IGFBP-3 preferentially bound to and was cross-linked to TbetaR-V in the presence of disuccinimidyl suberate. IGFBP-3 did not stimulate the cellular phosphorylation of Smad2 and Smad3, key transducers of the transforming growth factor-beta type I/type II receptor (TbetaR-I.TbetaR-II) heterocomplex-mediated signaling. These results suggest that IGFBP-3, -4, and -5 are specific ligands for TbetaR-V, which mediates the growth inhibitory response through a signaling pathway(s) distinct from that mediated by the TbetaR-I and TbetaR-II heterocomplex.
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Affiliation(s)
- S M Leal
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri 63104, USA
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Liu KX, Kato Y, Kaku TI, Matsumoto K, Nakamura T, Sugiyama Y. Protamine enhances the proliferative activity of hepatocyte growth factor in rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:G21-8. [PMID: 9458769 DOI: 10.1152/ajpgi.1998.274.1.g21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The effect of protamine on the proliferative activity of hepatocyte growth factor (HGF) was examined in alpha-naphthyl isothiocyanate-intoxicated rats. Protamine pre-injection increased the hepatocyte labeling index induced by HGF four- to fivefold. A similar effect was also observed in partially hepatectomized rats. Because a cell surface heparin-like substance can bind to HGF and protamine has an affinity for heparin, protamine may affect HGF pharmacokinetics. In fact, protamine injection caused a transient increase in plasma HGF concentrations after administration of HGF and, in vitro, protamine eluted HGF prebound to heparin-Sepharose. Protamine also reduced the plasma clearance of HGF and increased 2.5-fold the exposure of hepatocytes to HGF in vivo. The enhancing effect of protamine on the mitogenic response of hepatocytes to HGF was also observed in vitro (approximately 2-fold after protamine pretreatment compared with HGF alone), suggesting that the enhancing effect of protamine on HGF-induced liver regeneration results from dual effects exerted by protamine 1) lowering the overall elimination of HGF and 2) directly stimulating hepatocyte mitosis induced by HGF.
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Affiliation(s)
- K X Liu
- Faculty of Pharmaceutical Sciences, University of Tokyo, Japan
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Lokeshwar VB, Iida N, Bourguignon LY. The cell adhesion molecule, GP116, is a new CD44 variant (ex14/v10) involved in hyaluronic acid binding and endothelial cell proliferation. J Biol Chem 1996; 271:23853-64. [PMID: 8798616 DOI: 10.1074/jbc.271.39.23853] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In this study we have found that endothelial cells from different origins all contain a CD44-related transmembrane glycoprotein, named GP116. Using a bovine aortic endothelial cell line and a standard pulse-chase protocol, we show that GP116 is synthesized as a 52-kDa nascent polypeptide precursor (p52) which is processed to GP116 as follows, p52 --> p63/65 --> p82 --> p100 --> GP116. GP116 contains approximately 8 N- and approximately 11 O-linked oligosaccharide chains (but lacks glycosaminoglycans) and interacts directly with the cytoskeletal protein, ankyrin, both in vitro (Kd approximately 1.2 nM) and in vivo. The results of GP116 amino acid composition, reverse transcriptase-polymerase chain reaction, Southern blot, Northern blot, cloning, and sequence analyses indicate that endothelial cells express this new CD44 variant that contains an exon having significant homology with human CD44 exon 14 (ex14/v10). GP116, designated as CD44 (ex14/v10), has been shown to be a major hyaluronic acid (HA) receptor (Kd approximately 0.5-0.8 nM) responsible for cell adhesion. Most importantly, we have found that the interaction between CD44(ex14/v10) and HA or a small fragment of HA (10-15 disaccharide units) induces a mitogenic response in endothelial cells. These findings suggest that this CD44 variant plays an important role in regulating endothelial cell proliferation.
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Affiliation(s)
- V B Lokeshwar
- Department of Cell Biology and Anatomy, University of Miami School of Medicine, Miami, Florida 33101, USA
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Fontanini G, Vignati S, Bigini D, Mussi A, Lucchi H, Angeletti CA, Pingitore R, Pepe S, Basolo F, Bevilacqua G. Epidermal growth factor receptor (EGFr) expression in non-small cell lung carcinomas correlates with metastatic involvement of hilar and mediastinal lymph nodes in the squamous subtype. Eur J Cancer 1995; 31A:178-83. [PMID: 7718322 DOI: 10.1016/0959-8049(93)00421-m] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Epidermal growth factor receptor (EGFr) levels were evaluated in paraffin-embedded tumour specimens of non-small cell lung cancer (NSCLC) from 176 patients who underwent surgical resection. The EGFr expression was evaluated by immunocytochemical assay using a monoclonal antibody which recognises the external domain of the receptor. EGFr immunoreactivity was significantly higher in squamous than in non-squamous cell carcinomas (P = 0.0009). Hilar and/or mediastinal nodal involvement was found in 29 of 105 (27.4%) squamous cancers, and in this group of patients, the mean of EGFr positive cells was significantly higher than that of patients without nodal involvement (P = 0.01). No significant correlations were found between the expression of EGFr and other clinicopathological or biological parameters such as T-status, grading, proliferative activity. EGFR is suggested to represent a useful indicator of nodal metastasis in NSCLC.
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Elexpuru A, Soriano M, Villalobo A. Characterization of the epidermal growth factor receptor from Ehrlich ascites tumor cells. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1994; 375:293-8. [PMID: 8060539 DOI: 10.1515/bchm3.1994.375.4.293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have identified the 170 kDa epidermal growth factor (EGF) receptor in crude membrane fractions isolated from Ehrlich ascites tumor cells by its EGF-dependent phosphorylation with [gamma-32P]ATP. An apparent affinity constant for the ligand of 40-50 nM, based on the extent of its EGF-dependent phosphorylation, was calculated. [125I]EGF binds to the 170 kDa receptor and Scatchard plot analysis shows high affinity and low affinity Kds of 1.7 nM and 24 nM, respectively, in whole cells, and 0.2-0.8 nM and 39-116 nM, respectively, in isolated non-phosphorylated membrane fractions. We have estimated the presence of 48 x 10(3) high affinity and 275 x 10(3) low affinity EGF binding sites per tumor cell. Phosphoamino acid analysis shows EGF-dependent phosphorylation of tyrosine and serine residues. A polyclonal antibody to a human EGF receptor/c-erbB-2 product common cytoplasmic domain epitope immunoprecipitates a 45 kDa phosphopolypeptide from the tumor membrane fractions and from whole cell lysates. Phosphoamino acid analysis of the immunoprecipitated 45 kDa phosphopolypeptide shows the presence of phosphoserine. The immunoprecipitated 45 kDa polypeptide is able to undergo EGF-independent phosphorylation, although no significant protein kinase activity towards exogenous substrates is detected.
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Affiliation(s)
- A Elexpuru
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas Arturo Duperier 4, Madrid, Spain
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Schwabe M, Zhao J, Kung H. Differential expression and ligand-induced modulation of the human interleukin-6 receptor on interleukin-6-responsive cells. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37268-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Membrane Receptors. Mol Endocrinol 1994. [DOI: 10.1016/b978-0-12-111231-8.50011-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Mulherkar R, Rao R, Rao L, Patki V, Chauhan VS, Deo MG. Enhancing factor protein from mouse small intestines belongs to the phospholipase A2 family. FEBS Lett 1993; 317:263-6. [PMID: 8425615 DOI: 10.1016/0014-5793(93)81289-c] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Enhancing factor (EF), a growth regulatory molecule, isolated from mouse small intestines, has been well characterized in this laboratory. It increases the binding of epidermal growth factor in a unique manner via its own receptor. In the first 20 N-terminal amino acids sequenced, EF showed 50% homology to human Group II phospholipase A2 (PLA2). Here we propose that EF is yet another, unidentified isoform of PLA2 which regulates cell proliferation via modulation of EGF binding. To our knowledge, this is the first report implicating PLA2-II-like molecules in growth regulation.
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Affiliation(s)
- R Mulherkar
- Cell and Developmental Pathology Division, Tata Memorial Centre, Bombay, India
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Eriotou-Bargiota E, Xue CB, Naider F, Becker JM. Antagonistic and synergistic peptide analogues of the tridecapeptide mating pheromone of Saccharomyces cerevisiae. Biochemistry 1992; 31:551-7. [PMID: 1310042 DOI: 10.1021/bi00117a036] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Biologically inactive, truncated analogues of the Saccharomyces cerevisiae alpha-mating factor (WHWLQLKPGQPMY) either antagonized or synergized the activity of the native pheromone. An amino-terminal truncated pheromone [WLQLKPGQP(Nle)Y] had no activity by itself, but the analogue acted as an antagonist by competing with binding and activity of the mating factor. In contrast, a carboxyl-terminal truncated pheromone [WHWLQLKPGQP] was not active by itself nor did the peptide compete with alpha-factor for binding to the alpha-factor receptor, but it acted as a synergist by causing a marked increase in the activity of alpha-factor. The observation that residues near the amino terminus may be involved in signal transduction whereas those near the carboxyl terminus influence binding allows us to separate binding and signal transduction in the yeast pheromone response pathway. If found for other hormone-receptor systems, synergists may have potential as therapeutic compounds.
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Affiliation(s)
- E Eriotou-Bargiota
- Department of Microbiology, University of Tennessee, Knoxville 37996-0845
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Chauhan VP, Chauhan A. Protamine induces autophosphorylation of protein kinase C: stimulation of protein kinase C-mediated protamine phosphorylation by histone. Life Sci 1992; 51:537-44. [PMID: 1640802 DOI: 10.1016/0024-3205(92)90031-j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Protein kinase C (PKC), a protein phosphorylating enzyme, is characterized by its need for an acidic phospholipid and for activators such as Ca2+ and diacylglycerol. The substrate commonly used in experiments with PKC is a basic protein, histone III-S, which needs the activators mentioned. However, protamine, a natural basic substrate for PKC, does not require the presence of cofactor/activator. We report here that protamine can induce the autophosphorylation of PKC in the absence of any PKC-cofactor or activator; this may represent a possible mechanism of cofactor-independent phosphorylation of this protein. It was investigated if protamine itself can act as a PKC-activator and stimulate histone phosphorylation in the manner of Ca2+ and phospholipids. Experiments however showed that protamine is not a general effector of PKC. On the contrary, histone stimulated PKC-mediated protamine phosphorylation and protamine-induced PKC-autophosphorylation. Histone alone did not induce PKC-autophosphorylation. Kinetic studies suggest that histone increases the maximal velocity (Vmax) of protamine kinase activity of PKC without affecting the affinity (Km). Other polycationic proteins such as polyarginine serine and polyarginine tyrosine were not found to influence PKC-mediated protamine phosphorylation, indicating that the observed effects are specific to histone, and are not general for all polycationic proteins. These results suggest that histone can modulate the protamine kinase activity of PKC by stimulating protamine-induced PKC-autophosphorylation.
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Affiliation(s)
- V P Chauhan
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314
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Nie Z, Ham RG. Protamine stimulates serum-free growth of human muscle cells. IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY : JOURNAL OF THE TISSUE CULTURE ASSOCIATION 1991; 27A:677-80. [PMID: 1917785 DOI: 10.1007/bf02633209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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