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Zerihun M, Rubin SJS, Silnitsky S, Qvit N. An Update on Protein Kinases as Therapeutic Targets-Part II: Peptides as Allosteric Protein Kinase C Modulators Targeting Protein-Protein Interactions. Int J Mol Sci 2023; 24:17504. [PMID: 38139336 PMCID: PMC10743673 DOI: 10.3390/ijms242417504] [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: 11/01/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Human protein kinases are highly-sought-after drug targets, historically harnessed for treating cancer, cardiovascular disease, and an increasing number of autoimmune and inflammatory conditions. Most current treatments involve small molecule protein kinase inhibitors that interact orthosterically with the protein kinase ATP-binding pocket. As a result, these compounds are often poorly selective and highly toxic. Part I of this series reviews the role of PKC isoforms in various human diseases, featuring cancer and cardiovascular disease, as well as translational examples of PKC modulation applied to human health and disease. In the present Part II, we discuss alternative allosteric binding mechanisms for targeting PKC, as well as novel drug platforms, such as modified peptides. A major goal is to design protein kinase modulators with enhanced selectivity and improved pharmacological properties. To this end, we use molecular docking analysis to predict the mechanisms of action for inhibitor-kinase interactions that can facilitate the development of next-generation PKC modulators.
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Affiliation(s)
- Mulate Zerihun
- The Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Henrietta Szold St. 8, P.O. Box 1589, Safed 1311502, Israel; (M.Z.); (S.S.)
| | - Samuel J. S. Rubin
- Department of Medicine, School of Medicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94305, USA;
| | - Shmuel Silnitsky
- The Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Henrietta Szold St. 8, P.O. Box 1589, Safed 1311502, Israel; (M.Z.); (S.S.)
| | - Nir Qvit
- The Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Henrietta Szold St. 8, P.O. Box 1589, Safed 1311502, Israel; (M.Z.); (S.S.)
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de Bont HBA, van Boom JH, Liskamp RMJ. A convenient synthesis of a lipopeptide containing a diacylglycerol moiety: Preparation of a potential inhibitor of protein kinase C. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19921110504] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Metafora V, Franco P, Massa O, Morelli F, Stiuso P, Ferranti P, Mamone G, Malorni A, Stoppelli MP, Metafora S. Phosphorylation of seminal vesicle protein IV on Ser58 enhances its peroxidase-stimulating activity. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:3858-69. [PMID: 11432754 DOI: 10.1046/j.1432-1327.2001.02312.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this study we show that SV-IV, a major immunomodulatory, anti-inflammatory, and sperm immunoprotective protein secreted from the rat seminal vesicle epithelium, acts in vitro as a substrate of protein kinase C (PKC) competing efficiently with H1 histone, a very well known PKC substrate. Electrospray mass spectrometry (ES-MS) analysis demonstrated that approximately 10% of the native SV-IV molecules were phosphorylated by PKC and that such a modification involved only a single serine residue (Ser58) out of the 22 occurring in the protein. Interestingly, this modification produced a substantial enhancement (approximately 50%) of the native SV-IV's ability to stimulate the activity of both horseradish peroxidase (POD) and selenium-dependent glutathione peroxidase (GPX), an enzyme that is known to protect the mammalian spermatozoa from oxidative stress and loss of motility in the female genital tract following ejaculation. In contrast, the phosphorylation of SV-IV on Ser58 did not produce any effect on the anti-inflammatory properties of SV-IV, as measured by its ability to inhibit the phospholipase A2.
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Affiliation(s)
- V Metafora
- CNR International Institute of Genetics and Biophysics, Naples, Italy
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4
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Ward NE, Gravitt KR, O'Brian CA. Irreversible inactivation of protein kinase C by a peptide-substrate analog. J Biol Chem 1995; 270:8056-60. [PMID: 7713907 DOI: 10.1074/jbc.270.14.8056] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Protein kinase C (PKC) is a phospholipid-dependent isozyme family that plays a pivotal role in mammalian signal-transduction pathways that mediate cell growth and differentiation and pathological developments, such as the acquisition of drug resistance by cancer cells. Several peptide-substrate analogs have been shown to reversibly inhibit PKC with high potency and selectivity, but peptide-substrate analogs that antagonize PKC by forming a covalent complex with the enzyme have not been reported. The development of active site-directed irreversible inactivators of PKC could provide new insights into the catalytic mechanism and might ultimately lead to the design of novel therapeutics targeted at PKC. In this report, we show that the peptide-substrate analog Arg-Lys-Arg-Cys-Leu-Arg-Arg-Leu (RKRCLRRL) irreversibly inactivates PKC in a dithiothreitol-sensitive manner. The inactivation mechanism most consistent with our results is the formation of a covalent linkage between the inhibitor-peptide and the enzyme at its active-site. Limited proteolysis of PKC produces a catalytic-domain fragment that is independent of the phospholipid cofactor. RKRCLRRL antagonized the histone kinase activity of PKC and its catalytic-domain fragment with similar efficacies, achieving > 50% inactivation at an RKRCLRRL concentration of 10 microM. In contrast, RKRCLRRL analogs with single amino acid substitutions at Cys were non-inhibitory. The inactivated complex of the catalytic-domain fragment and RKRCLRRL was stable upon dilution, and the inactivation of PKC and the catalytic-domain fragment by RKRCLRRL was quenched by dithiothreitol, providing evidence that the enzyme and the synthetic peptide may be covalently linked in an inactivated complex by a disulfide bond. Substrates and substrate analogs protected the catalytic-domain fragment against inactivation by RKRCLRRL, providing evidence that inactivation entailed binding of RKRCLRRL at the active-site of the enzyme. S-Thiolation is the formation of mixed disulfides between proteins and low molecular weight thiols. PKC is thought to have a highly reactive Cys residue in its active-site, and Cys residues that are flanked by basic residues, as is the case in RKRCLRRL, display enhanced reactivity. Our results support an inactivation mechanism that entails S-thiolation of the active-site of PKC by RKRCLRRL. This is the first report of irreversible inactivation of PKC by an active site-directed peptide.
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Affiliation(s)
- N E Ward
- Department of Cell Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA
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Affiliation(s)
- P C Gordge
- Department of Clinical Oncology, University of Edinburgh, Western General Hospital, U.K
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6
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Abstract
Multiple sclerosis (MS) is characterized by the active degradation of central nervous system myelin, a multilamellar membrane system that insulates nerve axons. MS arises from complex interactions between genetic, immunological, infective, and biochemical mechanisms. Although the circumstances of MS etiology remain hypothetical, one persistent theme involves immune system recognition of myelin-specific antigens derived from myelin basic protein, the most abundant extrinsic myelin membrane protein, and/or another equally suitable myelin protein or lipid. Knowledge of the biochemical and physical-chemical properties of myelin proteins, and lipids, particularly their composition, organization, structure, and accessibility with respect to the compacted myelin multilayers, thus becomes central to understanding how and why these antigens become selected during the development of MS. This article focuses on the current understanding of the molecular basis of MS as it may relate to the protein and lipid components of myelin, which dictate myelin morphology on the basis of protein-lipid and lipid-lipid interactions, and the relationship, if any, between the protein/lipid components and the destruction of myelin in pathological situations.
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Affiliation(s)
- K A Williams
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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7
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Abstract
Multiple sclerosis (MS) and a number of related distinctive diseases are characterized by the active degradation of central nervous system (CNS) myelin, an axonal sheath comprised essentially of proteins and lipids. These demyelinating diseases appear to arise from complex interactions of genetic, immunological, infective, and biochemical mechanisms. While circumstances of MS etiology remain hypothetical, one persistent theme involves recognition by the immune system of myelin-specific antigens derived from myelin basic protein (MBP), the most abundant extrinsic myelin membrane protein, and/or another equally susceptible myelin protein or lipid component. Knowledge of the biochemical and physical-chemical properties of myelin proteins and lipids, particularly their composition, organization, structure, and accessibility with respect to the compacted myelin multilayers, thus becomes central to the understanding of how and why these antigens become selected during the development of MS. This review focuses on current understanding of the molecular basis underlying demyelinating disease as it may relate to the impact of the various protein and lipid components on myelin morphology; the precise molecular architecture of this membrane as dictated by protein-lipid and lipid-lipid interactions; and the relationship, if any, between the protein/lipid components and the destruction of myelin in pathological situations.
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Affiliation(s)
- C M Deber
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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Lowndes JM, Hokin-Neaverson M, Bertics PJ. Kinetics of phosphorylation of Na+/K(+)-ATPase by protein kinase C. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1052:143-51. [PMID: 2157496 DOI: 10.1016/0167-4889(90)90069-p] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The kinetics of phosphorylation of an integral membrane enzyme, Na+/K(+)-ATPase, by calcium- and phospholipid-dependent protein kinase C (PKC) were characterized in vitro. The phosphorylation by PKC occurred on the catalytic alpha-subunit of Na+/K(+)-ATPase in preparations of purified enzyme from dog kidney and duck salt-gland and in preparations of duck salt-gland microsomes. The phosphorylation required calcium (Ka approximately 1.0 microM) and was stimulated by tumor-promoting phorbol ester (12-O-tetradecanoylphorbol 13-acetate) in the presence of a low concentration of calcium (0.1 microM). PKC phosphorylation of Na+/K(+)-ATPase was rapid and plateaued within 30 min. The apparent Km of PKC for Na+/K(+)-ATPase as a substrate was 0.5 microM for dog kidney enzyme and 0.3 microM for duck salt-gland enzyme. Apparent substrate inhibition of PKC activity was observed at concentrations of purified salt-gland Na+/K(+)-ATPase greater than 1.0 microM. Phosphorylation of purified kidney and salt-gland Na+/K+ ATPases occurred at both serine and threonine residues. The 32P-phosphopeptide pattern on 15% sodium dodecyl sulfate-polyacrylamide gel electrophoresis after hydroxylamine cleavage of pure 32P-phosphorylated alpha subunit was the same for the two sources of enzyme, which suggests that the phosphorylation sites are similar. The results indicate that Na+/K(+)-ATPase may serve as a substrate for PKC phosphorylation in intact cells and that the Na+/K(+)-ATPase could be a useful in vitro model substrate for PKC interaction with integral membrane proteins.
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Affiliation(s)
- J M Lowndes
- Department of Physiological Chemistry, University of Wisconsin School of Medicine, Madison
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Pearson JD, DeWald DB, Mathews WR, Mozier NM, Zürcher-Neely HA, Heinrikson RL, Morris MA, McCubbin WD, McDonald JR, Fraser ED. Amino acid sequence and characterization of a protein inhibitor of protein kinase C. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39603-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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10
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Palczewski K, Arendt A, McDowell JH, Hargrave PA. Substrate recognition determinants for rhodopsin kinase: studies with synthetic peptides, polyanions, and polycations. Biochemistry 1989; 28:8764-70. [PMID: 2605220 DOI: 10.1021/bi00448a013] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Rhodopsin kinase phosphorylates serine- and threonine-containing peptides from bovine rhodopsin's carboxyl-terminal sequence. Km's for the peptides decrease as the length of the peptide is increased over the range 12-31 amino acids, reaching 1.7 mM for peptide 318-348 from the rhodopsin sequence. The Km for phosphorylation of rhodopsin is about 10(3) lower than that for the peptides, which suggests that binding of rhodopsin kinase to its substrate, photolyzed rhodopsin, involves more than just binding to the carboxyl-terminal peptide region that is to be phosphorylated. A synthetic peptide from the rhodopsin sequence that contains both serines and threonines is improved as a substrate by substitution of serines for the threonines, suggesting that serine residues are preferred as substrates. Analogous 25 amino acid peptides from the human red or green cone visual pigment, a beta-adrenergic receptor, or M1 muscarinic acetylcholine receptors are better substrates for bovine rhodopsin kinase than is the peptide from bovine rhodopsin. An acidic serine-containing peptide from a non-receptor protein, alpha s1B-casein, is also a good substrate for rhodopsin kinase. However, many basic peptides that are substrates for other protein kinases--histone IIA, histone IIS, clupeine, salmine, and a neurofilament peptide--are not phosphorylated by rhodopsin kinase. Polycations such as spermine or spermidine are nonessential activators of phosphorylation of rhodopsin or its synthetic peptide 324-348. Polyanions such as poly(aspartic acid), dextran sulfate, or poly(adenylic acid) inhibit the kinase. Poly(L-aspartic acid) is a competitive inhibitor with respect to rhodopsin (KI = 300 microM) and shows mixed type inhibition with respect to ATP.
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Affiliation(s)
- K Palczewski
- Department of Ophthalmology, University of Florida, Gainesville 32610
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de Bont HB, Liskamp RM, O'Brian CA, Erkelens C, Veeneman GH, van Boom JH. Synthesis of a substrate of protein kinase C and its corresponding phosphopeptide. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1989; 33:115-23. [PMID: 2707968 DOI: 10.1111/j.1399-3011.1989.tb00196.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The syntheses of a protein kinase C (PKC) peptide substrate, H-Lys-Arg-Thr-Leu-Arg-OH, and a phosphopeptide analog of the synthetic substrate, H-Lys-Arg-Thr(P)-Leu-Arg-OH, are reported. PKC phosphorylates the peptide with an apparent KM of 0.30 +/- 0.04 mM and an apparent Vmax equal to one-tenth that of histone III-S. The synthesis of the phosphopeptide features a recently developed convenient phosphorylation procedure for serine and threonine using N,N-diethylamino-dibenzylphosphoramidite. A complete characterization of the PKC substrate and its corresponding phosphopeptide by C-H COSY 2D n.m.r. is included.
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Affiliation(s)
- H B de Bont
- Dept. of Organic Chemistry, Gorlaeus Laboratories, University of Leiden, The Netherlands
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12
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Charp PA, Rice WG, Raynor RL, Reimund E, Kinkade JM, Ganz T, Selsted ME, Lehrer RI, Kuo JF. Inhibition of protein kinase C by defensins, antibiotic peptides from human neutrophils. Biochem Pharmacol 1988; 37:951-6. [PMID: 3345204 DOI: 10.1016/0006-2952(88)90187-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Defensins, human neutrophil peptide (HNP) antibiotics, potently inhibited phospholipid/Ca2+ protein kinase (protein kinase C, PKC) and phosphorylation of endogenous proteins from rat brains catalyzed by the enzyme. Of the three defensin peptides, HNP-2 appeared to be more potent than HNP-1 and HNP-3. Kinetic studies indicated that defensins inhibited PKC noncompetitively with respect to phosphatidylserine (a phospholipid cofactor), Ca2+ (an activator), ATP (a phosphoryl donor) and histone H1 (a substrate protein) with Ki values ranging from 1.2 to 1.7 microM. Defensins, unlike polymyxin B (another peptide inhibitor of PKC), did not inhibit the binding of [3H]phorbol 12,13-dibutyrate to PKC; however, defensins, like polymyxin B, inhibited the PKC activity stimulated by 12-O-tetradecanoylphorbol-13-acetate. Defensins had little or no effect on myosin light chain kinase (a calmodulin/Ca2+-dependent protein kinase) and the holoenzyme or catalytic subunit of cyclic AMP-dependent protein kinase, indicating a specificity of action of defensins. It is suggested that defensins, among the most potent peptide inhibitors of PKC so far identified, may have profound effects on functions of neutrophils and other mammalian cells, in addition to their well-recognized antimicrobial activities.
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Affiliation(s)
- P A Charp
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322
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Endogenous 1,4-Dihydropyridine-Displacing Substances Acting on L-Type Ca2+ Channels: Isolation and Characterization of Fractions from Brain and Stomach. ACTA ACUST UNITED AC 1988. [DOI: 10.1007/978-3-642-73914-9_45] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Affiliation(s)
- J B Ulmer
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
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Ferrari S, Calderan A, Pinna LA. Mechanism of Ca2+ and phospholipid-independent protein phosphorylation by protein kinase C: protamines and related peptides as substrates and inhibitors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1988; 231:427-32. [PMID: 3414442 DOI: 10.1007/978-1-4684-9042-8_34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- S Ferrari
- Istituto di Chimica Biologica, Università di Padova, Italy
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Blake AD, Mumford RA, Strout HV, Slater EE, Strader CD. Synthetic segments of the mammalian beta AR are preferentially recognized by cAMP-dependent protein kinase and protein kinase C. Biochem Biophys Res Commun 1987; 147:168-73. [PMID: 2820394 DOI: 10.1016/s0006-291x(87)80102-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Desensitization of the beta-adrenergic receptor has been correlated in some cell systems with receptor phosphorylation. Various kinases have been implicated in these phosphorylation processes, including both cAMP-dependent protein kinase and protein kinase C. In the present study, we have utilized the protein sequence information obtained from the cloning of the mammalian beta-adrenergic receptor to prepare synthetic peptides corresponding to regions of the receptor which would be predicted to act as possible substrates for these kinases in vivo. Two of these receptor-derived peptides were found to serve as substrates for these protein kinases. A peptide corresponding to amino acids 257-264 of the beta-receptor is the preferred substrate for the cAMP-dependent protein kinase, while protein kinase C showed a marked preference for phosphorylation of a peptide corresponding to residues 341-351 of the beta-adrenergic receptor.
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McDonald JR, Gröschel-Stewart U, Walsh MP. Properties and distribution of the protein inhibitor (Mr 17,000) of protein kinase C. Biochem J 1987; 242:695-705. [PMID: 3593270 PMCID: PMC1147767 DOI: 10.1042/bj2420695] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ca2+-dependent hydrophobic-interaction chromatography is a powerful tool for the identification and isolation of a variety of Ca2+-binding proteins which expose a hydrophobic site(s) in the presence of Ca2+ [Gopalakrishna & Anderson (1982) Biochem. Biophys. Res. Commun. 104, 830-836; Walsh, Valentine, Ngai, Carruthers & Hollenberg (1984) Biochem. J. 224, 117-127; McDonald & Walsh (1985) Biochem. J. 232, 559-567]. Using this approach, we isolated two potent and specific protein inhibitors of protein kinase C, of 17 kDa [McDonald & Walsh (1985) Biochem. J. 232, 559-567] and 12 kDa [McDonald & Walsh (1986) Biochem. Soc. Trans. 14, 585-586]. Although these inhibitors were purified by Ca2+-dependent hydrophobic-interaction chromatography and exhibit properties similar to those of calmodulin and related Ca2+-binding proteins, we were unable to demonstrate high-affinity Ca2+ binding to these inhibitors, using equilibrium dialysis. Protein kinase C exhibited half-maximal activity at 0.6 microM-Ca2+ in the presence of phospholipid and diacylglycerol, and complete inhibition by both inhibitors was observed over the range of Ca2+ concentrations examined (10 nM-10 microM). These observations suggest that the inhibitory action of these proteins does not require Ca2+. The inclusion of proteinase inhibitors during isolation of the kinase C inhibitors, as well as two-dimensional peptide mapping and amino acid analysis of the isolated proteins, suggested that the 12 kDa inhibitor is a proteolytic fragment of the 17 kDa protein which is generated during purification. Antibodies raised in rabbits against the bovine brain 17 kDa inhibitor were shown to be specific by Western immunoblotting and the competitive enzyme-linked immunosorbent assay method and were used to study the tissue and species distribution of this protein. The inhibitor was found to be present in several bovine, murine, avian and human tissues, consistent with a role in the regulation of a variety of physiological functions involving the widely distributed protein kinase C.
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Kase H, Iwahashi K, Nakanishi S, Matsuda Y, Yamada K, Takahashi M, Murakata C, Sato A, Kaneko M. K-252 compounds, novel and potent inhibitors of protein kinase C and cyclic nucleotide-dependent protein kinases. Biochem Biophys Res Commun 1987; 142:436-40. [PMID: 3028414 DOI: 10.1016/0006-291x(87)90293-2] [Citation(s) in RCA: 754] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
K-252 compounds (K-252a and b isolated from Nocardiopsis sp. (1) and their synthetic derivatives) were found to inhibit cyclic nucleotide-dependent protein kinases and protein kinase C to various extents. The inhibitions were of the competitive type with respect to ATP. K-252a was a non-selective inhibitor for these three protein kinases with Ki values 18-25 nM. K-252b showed a comparable potency for protein kinase C (Ki, 20nM), whereas inhibitory potencies for cyclic nucleotide-dependent protein kinases were reduced. KT5720 and KT5822 selectively inhibited cAMP-dependent (Ki, 60nM) and cGMP-dependent (Ki, 2.4nM) protein kinases, respectively.
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Park GH, Chanderkar LP, Paik WK, Kim S. Myelin basic protein inhibits histone-specific protein methylase I. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 874:30-6. [PMID: 2429705 DOI: 10.1016/0167-4838(86)90098-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bovine brain myelin basic protein, free of associated proteolytic activity, was found to be a specific inhibitor of histone-specific protein methylase I (S-adenosyl-L-methionine:protein-L-arginine N-methyltransferase, EC 2.1.1.23) purified from bovine brain. 50% of the methyl group incorporation into the histone substrate catalyzed by the methylase I was inhibited by myelin basic protein at a concentration of 0.326 mM. However, neither of the peptide fragments (residues 1-116 and residues 117-170) generated by the chemical cleavage of myelin basic protein at the tryptophan residue retained the inhibitory activity for histone-specific protein methylase I. Proteins such as gamma-globulin, bovine serum albumin, bovine pancreatic ribonuclease and polyarginine did not exhibit significant inhibitory activity toward the enzyme. The Ki value for myelin basic protein was estimated to be 3.42 X 10(-5) M for histone-specific protein methylase I and the nature of the inhibition was uncompetitive toward histone substrate.
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