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Stochastic Induction of Long-Term Potentiation and Long-Term Depression. Sci Rep 2016; 6:30899. [PMID: 27485552 PMCID: PMC4971485 DOI: 10.1038/srep30899] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/10/2016] [Indexed: 01/23/2023] Open
Abstract
Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca2+]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca2+ induced both processes stochastically. The magnitudes of the Ca2+ signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca2+ thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses.
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2
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Profiling of drug binding proteins by monolithic affinity chromatography in combination with liquid chromatography-tandem mass spectrometry. J Chromatogr A 2014; 1359:84-90. [PMID: 25064533 DOI: 10.1016/j.chroma.2014.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/07/2014] [Accepted: 07/10/2014] [Indexed: 01/11/2023]
Abstract
A new approach for proteome-wide profiling drug binding proteins by using monolithic capillary affinity chromatography in combination with HPLC-MS/MS is reported. Two immunosuppresive drugs, namely FK506 and cyclosporin A, were utilized as the experimental models for proof-of-concept. The monolithic capillary affinity columns were prepared through a single-step copolymerization of the drug derivatives with glycidyl methacrylate and ethylene dimethacrylate. The capillary chromatography with the affinity monolithic column facilitates the purification of the drug binding proteins from the cell lysate. By combining the capillary affinity column purification and the shot-gun proteomic analysis, totally 33 FK506- and 32 CsA-binding proteins including all the literature reported target proteins of these two drugs were identified. Among them, two proteins, namely voltage-dependent anion-selective channel protein 1 and serine/threonine-protein phosphatase PGAM5 were verified by using the recombinant proteins. The result supports that the monolithic capillary affinity chromatography is likely to become a valuable tool for profiling of binding proteins of small molecular drugs as well as bioactive compounds.
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Wang Y, Tandan S, Hill JA. Calcineurin-dependent ion channel regulation in heart. Trends Cardiovasc Med 2013; 24:14-22. [PMID: 23809405 DOI: 10.1016/j.tcm.2013.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/20/2013] [Accepted: 05/21/2013] [Indexed: 02/05/2023]
Abstract
Calcineurin, a serine-threonine-specific, Ca(2+)-calmodulin-activated protein phosphatase, conserved from yeast to humans, plays a key role in regulating cardiac development, hypertrophy, and pathological remodeling. Recent studies demonstrate that calcineurin regulates cardiomyocyte ion channels and receptors in a manner which often entails direct interaction with these target proteins. Here, we review the current state of knowledge of calcineurin-mediated regulation of ion channels in the myocardium with emphasis on the transient outward potassium current (Ito) and L-type calcium current (ICa,L). We go on to discuss unanswered questions that surround these observations and provide perspective on future directions in this exciting field.
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Affiliation(s)
- Yanggan Wang
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China; Department of Pediatrics, Emory University, Atlanta, GA, USA.
| | - Samvit Tandan
- Department of Internal Medicine (Cardiology), University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Joseph A Hill
- Department of Internal Medicine (Cardiology), University of Texas, Southwestern Medical Center, Dallas, TX, USA; Department of Molecular Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA.
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4
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Juvvadi PR, Fortwendel JR, Rogg LE, Burns KA, Randell SH, Steinbach WJ. Localization and activity of the calcineurin catalytic and regulatory subunit complex at the septum is essential for hyphal elongation and proper septation in Aspergillus fumigatus. Mol Microbiol 2011; 82:1235-59. [PMID: 22066998 DOI: 10.1111/j.1365-2958.2011.07886.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Calcineurin, a heterodimer composed of the catalytic (CnaA) and regulatory (CnaB) subunits, plays key roles in growth, virulence and stress responses of fungi. To investigate the contribution of CnaA and CnaB to hyphal growth and septation, ΔcnaB and ΔcnaAΔcnaB strains of Aspergillus fumigatus were constructed. CnaA colocalizes to the contractile actin ring early during septation and remains at the centre of the mature septum. While CnaB's septal localization is CnaA-dependent, CnaA's septal localization is CnaB-independent, but CnaB is required for CnaA's function at the septum. Catalytic null mutations in CnaA caused stunted growth despite septal localization of the calcineurin complex, indicating the requirement of calcineurin activity at the septum. Compared to the ΔcnaA and ΔcnaB strains, the ΔcnaAΔcnaB strain displayed more defective growth and aberrant septation. While three Ca(2+) -binding motifs in CnaB were sufficient for its association with CnaA at the septum, the amino-terminal arginine-rich domains (16-RRRR-19 and 44-RLRKR-48) are dispensable for septal localization, yet required for complete functionality. Mutation of the 51-KLDK-54 motif in CnaB causes its mislocalization from the septum to the nucleus, suggesting it is a nuclear export signal sequence. These findings confirm a cooperative role for the calcineurin complex in regulating hyphal growth and septation.
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Affiliation(s)
- Praveen Rao Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC, USA
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5
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Studies on the interactions of kaempferol to calcineurin by spectroscopic methods and docking. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:1269-75. [PMID: 19439201 DOI: 10.1016/j.bbapap.2009.04.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 04/23/2009] [Accepted: 04/27/2009] [Indexed: 01/05/2023]
Abstract
Kaempferol, in our previous study, was a new immunosuppressant on calcineurin (CN), the Ca(2+)/calmodulin (CaM)-dependent protein phosphatase. Here, we examined the interactions of kaempferol with CN by fluorescence spectroscopy (FS), circular dichroism spectroscopy (CD) and docking. Data of kaempferol with CN catalytic subunit (CN A) and its truncated mutant CNAa obtained by FS method showed that the binding stoichiometry of kaempferol/CN A was 1:1, catalytic domain of CN A was the concrete domain for kaempferol binding while other domains contributed a lot to this binding. Distances from kaempferol to each tryptophan (Trp) in CN A by energy transfer experiments and the subsequent docking study interestingly provided the same binding sites for kaempferol, which all located in the non-active site area of CN A catalytic domain, also consisted with our previous conclusion from CN activity assay. Furthermore, CD results showed a much tighter structure of CN A for the inhibitor binding; on the other hand, presence of Ca(2+) and Mn(2+) decreased kaempferol binding on CN A.
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7
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Klee CB, Draetta GF, Hubbard MJ. Calcineurin. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 61:149-200. [PMID: 2833077 DOI: 10.1002/9780470123072.ch4] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- C B Klee
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892
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8
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Hu L, Zhang B, Xiang B, Wei Q. Calcineurin B protects calcineurin A against denaturation by urea. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1700:141-4. [PMID: 15262222 DOI: 10.1016/j.bbapap.2004.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2004] [Revised: 05/10/2004] [Accepted: 05/14/2004] [Indexed: 11/30/2022]
Abstract
Calcineurin (CN), a heterodimer composed of a catalytic subunit, calcineurin A (CNA) and regulatory subunit, calcineurin B (CNB), is involved in many cellular processes. We investigated the denaturation of CNA by urea in the presence or absence of CNB and found that CNB protected CNA against urea. The phosphatase activity of CNA that had been exposed to low urea concentrations (below 4 M), in the presence CNB, was higher than that of the separately urea-treated subunits mixed just prior to assay. In order to analyze the protection of CNA by CNB, we investigated the K(m) and V(max), and intrinsic fluorescence, of CNA that had been exposed to various concentrations of urea in the presence or absence of CNB. CN had an increased V(max) and decreased K(m) when exposed to 1 to 2 M urea. In addition, the kinetic parameters and intensity of intrinsic fluorescence of the AB complex and isolated subunits were quite different in 3 M urea. These results indicate that CNB not only plays an important role in regulating CNA, but also protects it against denaturation by urea.
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Affiliation(s)
- Liya Hu
- Beijing Key Laboratory, Department of Biochemistry and Molecular Biology, Life Science Institute, Beijing Normal University, Beijing 100875, PR China
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9
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Takezawa D. Characterization of a novel plant PP2C-like protein Ser/Thr phosphatase as a calmodulin-binding protein. J Biol Chem 2003; 278:38076-83. [PMID: 12860996 DOI: 10.1074/jbc.m301369200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein phosphatases regulated by calmodulin (CaM) mediate the action of intracellular Ca2+ and modulate functions of various target proteins by dephosphorylation. In plants, however, the role of Ca2+ in the regulation of protein dephosphorylation is not well understood due to a lack of information on characteristics of CaM-regulated protein phosphatases. Screening of a cDNA library of the moss Physcomitrella patens by using 35S-labeled calmodulin as a ligand resulted in identification of a gene, PCaMPP, that encodes a protein serine/threonine phosphatase with 373 amino acids. PCaMPP had a catalytic domain with sequence similarity to type 2C protein phosphatases (PP2Cs) with six conserved metal-associating amino acid residues and also had an extra C-terminal domain. Recombinant GST fusion proteins of PCaMPP exhibited Mn2+-dependent phosphatase activity, and the activity was inhibited by pyrophosphate and 1 mm Ca2+ but not by okadaic acid, orthovanadate, or beta-glycerophosphate. Furthermore, the PCaMPP activity was increased 1.7-fold by addition of CaM at nanomolar concentrations. CaM binding assays using deletion proteins and a synthetic peptide revealed that the CaM-binding region resides within the basic amphiphilic amino acid region 324-346 in the C-terminal domain. The CaM-binding region had sequence similarity to amino acids in one of three alpha-helices in the C-terminal domain of human PP2Calpha, suggesting a novel role of the C-terminal domains for the phosphatase activity. These results provide the first evidence showing possible regulation of PP2C-related phosphatases by Ca2+/CaM in plants. Genes similar to PCaMPP were found in genomes of various higher plant species, suggesting that PCaMPP-type protein phosphatases are conserved in land plants.
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Affiliation(s)
- Daisuke Takezawa
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
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10
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Mitchell PO, Mills ST, Pavlath GK. Calcineurin differentially regulates maintenance and growth of phenotypically distinct muscles. Am J Physiol Cell Physiol 2002; 282:C984-92. [PMID: 11940513 DOI: 10.1152/ajpcell.00483.2001] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Adequate muscle mass is critical for human health. The molecular pathways regulating maintenance and growth of adult skeletal muscle are little understood. Calcineurin (CN) is implicated as a key signaling molecule in hypertrophy. Whether CN is involved in all forms of muscle growth or in different muscles is unknown. Here, we examine the role of CN in regulating maintenance of muscle size and growth of atrophied muscle in the soleus (slow) and plantaris (fast). The CN inhibitor cyclosporin A (CsA) differentially affects muscle growth and maintenance depending on muscle phenotype. The plantaris is more severely affected by CsA than the soleus in both growth conditions. One-week vs. 2-wk CsA treatment suggests that both CN-dependent and CN-independent growth occur in the atrophied soleus, whereas plantaris growth appears to be totally CN dependent. Our results suggest that CN regulates multiple types of muscle growth, depending both on muscle phenotype and stage of myofiber growth. Differential expression of components of the CN pathway occurs and may contribute to the differences between muscles.
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Affiliation(s)
- Patrick O Mitchell
- Department of Pharmacology and Graduate Program in Cell and Developmental Biology, Emory University, Atlanta, Georgia 30322, USA
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11
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Zeng H, Chattarji S, Barbarosie M, Rondi-Reig L, Philpot BD, Miyakawa T, Bear MF, Tonegawa S. Forebrain-specific calcineurin knockout selectively impairs bidirectional synaptic plasticity and working/episodic-like memory. Cell 2001; 107:617-29. [PMID: 11733061 DOI: 10.1016/s0092-8674(01)00585-2] [Citation(s) in RCA: 404] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Calcineurin is a calcium-dependent protein phosphatase that has been implicated in various aspects of synaptic plasticity. By using conditional gene-targeting techniques, we created mice in which calcineurin activity is disrupted specifically in the adult forebrain. At hippocampal Schaffer collateral-CA1 synapses, LTD was significantly diminished, and there was a significant shift in the LTD/LTP modification threshold in mutant mice. Strikingly, although performance was normal in hippocampus-dependent reference memory tasks, including contextual fear conditioning and the Morris water maze, the mutant mice were impaired in hippocampus-dependent working and episodic-like memory tasks, including the delayed matching-to-place task and the radial maze task. Our results define a critical role for calcineurin in bidirectional synaptic plasticity and suggest a novel mechanistic distinction between working/episodic-like memory and reference memory.
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Affiliation(s)
- H Zeng
- Howard Hughes Medical Institute, RIKEN-MIT Neuroscience Research Center, Center for Learning & Memory, Departments of Biology and Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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12
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Feng B, Stemmer PM. Ca2+ binding site 2 in calcineurin-B modulates calmodulin-dependent calcineurin phosphatase activity. Biochemistry 2001; 40:8808-14. [PMID: 11467941 DOI: 10.1021/bi0025161] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calcineurin is the Ca(2+)- and calmodulin-dependent Ser/Thr phosphatase. Human calcineurin-Aalpha and wild-type or mutated calcineurin-Bs were coexpressed in Escherichia coli and purified by calmodulin-Sepharose affinity chromatography. Four calcineurin-B mutants were studied. Each had a single conserved Glu in the 12th position of one EF-hand Ca(2+) binding site replaced by a Lys, resulting in the loss of Ca(2+) binding to that site. Phosphatase activities of the enzymes toward a (32)P-labeled phosphopeptide substrate were measured. Inactivating Ca(2+) binding sites 1, 2, or 3 in calcineurin-B reduced Ca(2+)-dependent phosphatase activity of the enzymes in the absence of calmodulin with the site 2 mutation being most effective. Inactivating Ca(2+) binding site 4 did not change enzyme activity or sensitivity to Ca(2+) in either the absence or presence of calmodulin. The calmodulin-dependent phosphatase activity of the enzymes containing site 1, 2, or 3 mutations in calcineurin-B was also decreased compared to enzyme with wild-type calcineurin-B. Of these enzymes, the one with the site 2 mutation was most profoundly affected as determined by the magnitude of the shift in Ca(2+) concentration dependence. Binding of a fluorescein-labeled calmodulin to the wild-type and the site 2 mutant enzymes was examined using fluorescence polarization measurements. The decrease in Ca(2+) sensitivity for the enzyme with calcineurin-B site 2 inactivated is apparently due to a decrease in the affinity of that enzyme for calmodulin at low Ca(2+) concentrations. These data support a role for Ca(2+) binding site 3 in the carboxyl half of calcineurin-B in transmitting the Ca(2+) signal to calcineurin-A and indicate that site 2 in the amino half of calcineurin-B is critical for enzyme activation.
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Affiliation(s)
- B Feng
- Department of Pediatrics, College of Medicine, 986255 Nebraska Medical Center, Omaha, Nebraska 68198-6255, USA
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Fox DS, Cruz MC, Sia RA, Ke H, Cox GM, Cardenas ME, Heitman J. Calcineurin regulatory subunit is essential for virulence and mediates interactions with FKBP12-FK506 in Cryptococcus neoformans. Mol Microbiol 2001; 39:835-49. [PMID: 11251806 DOI: 10.1046/j.1365-2958.2001.02295.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Calcineurin is a Ca2+-calmodulin-regulated protein phosphatase that is the target of the immunosuppressive drugs cyclosporin A and FK506. Calcineurin is a heterodimer composed of a catalytic A and a regulatory B subunit. In previous studies, the calcineurin A homologue was identified and shown to be required for growth at 37 degrees C and hence for virulence of the pathogenic fungus Cryptococcus neoformans. Here, we identify the gene encoding the calcineurin B regulatory subunit and demonstrate that calcineurin B is also required for growth at elevated temperature and virulence. We show that the FKR1-1 mutation, which confers dominant FK506 resistance, results from a 6 bp duplication generating a two-amino-acid insertion in the latch region of calcineurin B. This mutation was found to reduce FKBP12-FK506 binding to calcineurin both in vivo and in vitro. Molecular modelling based on the FKBP12-FK506-calcineurin crystal structure illustrates how this mutation perturbs drug interactions with the phosphatase target. In summary, our studies reveal a central role for calcineurin B in virulence and antifungal drug action in the human fungal pathogen C. neoformans.
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Affiliation(s)
- D S Fox
- Department of Genetics, 322 CARL Bldg., Box 3546, Duke University Medical Center, Research Drive, Durham, NC 27710, USA
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14
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Aramburu J, Rao A, Klee CB. Calcineurin: from structure to function. CURRENT TOPICS IN CELLULAR REGULATION 2000; 36:237-95. [PMID: 10842755 DOI: 10.1016/s0070-2137(01)80011-x] [Citation(s) in RCA: 248] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- J Aramburu
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
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15
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Abstract
Calcineurin is a serine-threonine specific Ca(2+)-calmodulin-activated protein phosphatase that is conserved from yeast to humans. Remarkably, this enzyme is the common target for two novel and structurally unrelated immunosuppressive antifungal drugs, cyclosporin A and FK506. Both drugs form complexes with abundant intracellular binding proteins, cyclosporin A with cyclophilin A and FK506 with FKBP 12, which bind to and inhibit calcineurin. The X-ray structure of an FKPB12-FK506-calcineurin AB ternary complex reveals that FKBP12-FK506 binds in a hydophobic groove between the calcineurin A catalytic and the regulatory B subunit, in accord with biochemical and genetic studies on inhibitor action. Calcineurin plays a key role in regulating the transcription factor NF-AT during T-cell activation, and in mediating responses of microorganisms to cation stress. These findings highlight the potential of yeast genetic studies to define novel drug targets and elucidate conserved elements of signal transduction cascades.
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Affiliation(s)
- C S Hemenway
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA, USA
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16
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Gao ZH, Zhong G. Calcineurin B- and calmodulin-binding preferences identified with phage-displayed peptide libraries. Gene X 1999; 228:51-9. [PMID: 10072758 DOI: 10.1016/s0378-1119(99)00007-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Calcineurin B (CnB) and calmodulin (CaM) are two structurally similar but functionally distinct 'EF-hand' Ca2+-binding proteins. CnB is the regulatory subunit of the CaM-stimulated protein phosphatase, calcineurin. CaM is a unique multifunctional protein that interacts with and modulates the activity of many target proteins. CnB and CaM are both required for the full activation of the phosphatase activity of calcineurin and are not interchangeable. The two proteins recognize distinct binding sites on calcineurin A subunit (CnA) and perform different functions. Phage-displayed peptide libraries (pIII and pVIII libraries) were screened with CnB and CaM to isolate peptides that could then be compared to determine if there were binding preferences of the two proteins. The Ca2+-dependent binding of phage-displayed peptides to CnB and CaM is specifically blocked by synthetic peptides derived from the CnB-binding domain of CnA and the CaM-binding domain of myosin light chain kinase respectively. Both CnB- and CaM-binding peptides have a high content of tryptophan and leucine, but CnB-binding peptides are more hydrophobic than CaM-binding peptides. CnB-binding peptides are negatively charged with clusters of hydrophobic residues rich in phenylalanine, whereas the CaM-binding peptides are positively charged and often contain an Arg/Lys-Trp motif. The binding preferences identified with peptide libraries are consistent with the features of the CnB-binding domains of all CnA isoforms and the CaM-binding domains of CaM targets.
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Affiliation(s)
- Z H Gao
- Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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17
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Leach KL. Protein Kinases and Phosphatases in Cellular Signaling. Compr Physiol 1998. [DOI: 10.1002/cphy.cp070110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Klee CB, Ren H, Wang X. Regulation of the calmodulin-stimulated protein phosphatase, calcineurin. J Biol Chem 1998; 273:13367-70. [PMID: 9593662 DOI: 10.1074/jbc.273.22.13367] [Citation(s) in RCA: 713] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- C B Klee
- Laboratory of Biochemistry, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Kissmehl R, Treptau T, Kottwitz B, Plattner H. Occurrence of a para-nitrophenyl phosphate-phosphatase with calcineurin-like characteristics in Paramecium tetraurelia. Arch Biochem Biophys 1997; 344:260-70. [PMID: 9264538 DOI: 10.1006/abbi.1997.0208] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Using para-nitrophenyl phosphate (pNPP) as a substrate for enzymatic activity, we sought to identify CaN in Paramecium. We isolated three different pNPP-phosphatases from the soluble fraction of Paramecium cells by anion-exchange and affinity column chromatographies. One, pNPP-phosphatase Peak I, is very similar to mammalian CaN. Divalent cation dependency, inhibition by calmodulin (CaM) antagonists (trifluoperazine, calmidazolium), and insensitivity to various phosphatase inhibitors (heparin, okadaic acid, sodium vanadate, etc.) show similarity to mammalian CaN rather than to any other Paramecium pNPP-hydrolyzing enzymes tested. Polyclonal antibodies against bovine brain CaN recognizing subunits A (61 or 58 kDa) and B (17 kDa) of brain CaN cross-reacted with a 63-kDa protein in fractions containing Peak IpNPP-phosphatase activity and coeluted calmodulin. Overlay assays using biotinylated brain calmodulin indicated Ca2+-dependent CaM-binding by the 63-kDa protein. A Ca2+-binding protein with the same electrophoretic mobility as CaN B (17 kDa) was also present, though in other fractions from DEAE-cellulose chromatography. This finding strongly suggests that, in the absence of Ca2+, both subunits, A and B, were separated either before or during chromatographic processing. Our data support the existence of both subunits of a CaN-like phosphatase in Paramecium cells.
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Affiliation(s)
- R Kissmehl
- Faculty of Biology, University of Konstanz, Germany.
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Hellstern S, Dammann H, Husain Q, Mutzel R. Overexpression, purification and characterization of Dictyostelium calcineurin A. Res Microbiol 1997; 148:335-43. [PMID: 9765812 DOI: 10.1016/s0923-2508(97)81589-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The catalytic subunit of Ca2+/calmodulin-dependent protein phosphatase (calcineurin A) was overexpressed about 50-fold in Dictyostelium discoideum cells transformed with a vector containing the cDNA for D. discoideum calcineurin A under control of the actin-6 promoter. In crude lysates from the overexpressing cell line, high Ca2+/calmodulin-stimulated phosphatase activity was detected. Calcineurin A was purified by anion exchange chromatography and calmodulin-Sepharose affinity chromatography, and the enzymatic activity of the isolated protein was characterized. Its phosphatase activity was strictly dependent on the addition of divalent metal ions such as Mg2+ or Mn2+. Disulphide-reducing agents increased the activity more than 10-fold. Ca2+/calmodulin stimulated the activity by a factor of 2.5-5. Despite the high extra Ca2+/calmodulin-dependent phosphatase activity, the overexpressing cell line showed no phenotypic aberrations.
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Affiliation(s)
- S Hellstern
- Fakultät fur Biologie, Universität Konstanz, Germany
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Abstract
Long-term potentiation (LTP) and long-term depression (LTD) in CA1 pyramidal neurons are both triggered by a postsynaptic rise in intracellular Ca2+ concentration ([Ca2+]i). We used photolysis of postsynaptic caged Ca2+ compounds to search for differential thresholds for activation of these processes. Long-lasting potentiation (LLP) resembling LTP, and long-lasting depression (LLD) resembling LTD, were evoked by [Ca2+]i elevations of comparable magnitude and duration in different cells. No distinctions in threshold for these processes were detectable. LLP was occluded by tetanically induced LTP and blocked by calmodulin inhibition, and LLD was occluded by electrically induced LTD and blocked by phosphatase inhibition.
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Affiliation(s)
- D Neveu
- Neurobiology Division, University of California, Berkeley, 94720, USA
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22
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Sikkink R, Haddy A, MacKelvie S, Mertz P, Litwiller R, Rusnak F. Calcineurin subunit interactions: mapping the calcineurin B binding domain on calcineurin A. Biochemistry 1995; 34:8348-56. [PMID: 7599126 DOI: 10.1021/bi00026a016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Recombinant forms of the A and B subunits of the protein phosphatase calcineurin were produced in Escherichia coli, reconstituted into a heterodimer and purified to homogeneity. The reconstituted heterodimer exhibited properties like that of bovine brain calcineurin. This included calmodulin-stimulated activity and a subunit stoichiometry and Stokes radius consistent with native-like structure. In order to map the region on the A subunit where calcineurin B binds, a series of overlapping 20-residue peptides corresponding to this putative domain were synthesized. Using isolated calcineurin A and B subunits, an assay that relied upon peptide inhibition of calcineurin B stimulation of calcineurin A activity was developed. All five peptides, but not a control peptide, inhibited calcineurin B-dependent stimulation of calcineurin A although with different potencies. The three most effective inhibitory peptides spanned calcineurin A residues 338-377. These three peptides also altered the electrophoretic mobility of the isolated calcineurin B subunit during native polyacrylamide gel electrophoresis indicating a direct interaction between these peptides and calcineurin B. The peptide corresponding to residues 348-367 was also able to block binding of calcineurin B to the catalytic subunit.
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Affiliation(s)
- R Sikkink
- Section of Hematology Research, Mayo Clinic & Foundation, Rochester, Minnesota 55905, USA
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23
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Chaudhuri B, Hämmerle M, Fürst P. The interaction between the catalytic A subunit of calcineurin and its autoinhibitory domain, in the yeast two-hybrid system, is disrupted by cyclosporin A and FK506. FEBS Lett 1995; 357:221-6. [PMID: 7528690 DOI: 10.1016/0014-5793(94)01365-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The Ca(2+)-calmodulin dependent protein phosphatase, calcineurin, is thought to mediate the action of the two immunosuppressants, cyclosporin A (CsA) and FK506. Calcineurin from all species consists of a catalytic A subunit and a regulatory peptide B, which plays an essential role in catalysis. The enzymatic function is probably also regulated by an autoinhibitory domain (AID) present in the catalytic subunit. We have used the yeast two-hybrid system to show that the putative AID of the yeast catalytic subunit Cna1 binds only to truncated Cna1, devoid of AID. Although deletion of the genes encoding the yeast catalytic subunits of calcineurin (CNA1 and CNA2) maintain the interaction, absence of the regulatory subunit Cnb1 prevents binding. Interestingly, both CsA and FK506 disrupt this interaction, whereas binding of Cna1 to calmodulin remains unaffected. This indicates that a simple cellular system, developed in yeast, could provide further insight into an understanding of calcineurin inhibition.
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Affiliation(s)
- B Chaudhuri
- Department of Core Drug Discovery Technologies (CDDT), Ciba-Geigy Ltd., Basel, Switzerland
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24
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Watanabe Y, Perrino BA, Chang BH, Soderling TR. Identification in the Calcineurin A Subunit of the Domain That Binds the Regulatory B Subunit. J Biol Chem 1995. [DOI: 10.1074/jbc.270.1.456] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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25
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26
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Burroughs SE, Horrocks WD, Ren H, Klee CB. Characterization of the lanthanide ion-binding properties of calcineurin-B using laser-induced luminescence spectroscopy. Biochemistry 1994; 33:10428-36. [PMID: 8068681 DOI: 10.1021/bi00200a026] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Calcineurin (CaN) is a Ca2+/calmodulin-dependent protein phosphatase found in brain and other tissues. It is a heterodimer consisting of a catalytic subunit (CaN-A) and a Ca(2+)-binding regulatory subunit (CaN-B). The primary structure of CaN-B indicates that it, like calmodulin, is an EF-hand protein and binds four Ca2+ ions. Eu3+, due to its favorable spectroscopic and chemical properties, has been substituted for Ca2+ in CaN-B to determine the metal ion-binding properties of this "calmodulin-like" protein. Excitation of the 7F0-->5D0 transition of Eu3+ results in a spectrum similar to that of calmodulin, consisting of three peaks. Analysis of the spectral titration curves reveals four Eu(3+)-binding sites in CaN-B. The affinities vary: sites I and II have dissociation constants of 1.0 +/- 0.2 and 1.6 +/- 0.4 microM, respectively; the values for sites III and IV are Kd = 140 +/- 20 and Kd = 20 +/- 10 nM, respectively. Binding of Tb3+ is slightly weaker. Tb3+ luminescence, sensitized by tyrosine, reveals that for lanthanides the highest affinity sites lie in the C-terminal domain. Energy transfer distance measurements between Eu3+ and Nd3+ in sites III and IV reveal a separation of 10.5 +/- 0.5 A, which suggests that these sites are arranged in a typical EF-hand pair. This information indicates that the overall structure of CaN-B is similar to the dumbbell-shaped proteins troponin-C and calmodulin, but is more like TnC in its metal-binding properties.
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Affiliation(s)
- S E Burroughs
- Department of Chemistry, Pennsylvania State University, University Park 16802
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27
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O'Keefe SJ, O'Neill EA. Cyclosporin A and FK-506: Immunosuppression, inhibition of transcription and the role of calcineurin. ACTA ACUST UNITED AC 1994. [DOI: 10.1007/bf02171738] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Parsons J, Wiederrecht G, Salowe S, Burbaum J, Rokosz L, Kincaid R, O'Keefe S. Regulation of calcineurin phosphatase activity and interaction with the FK-506.FK-506 binding protein complex. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32213-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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29
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Stemmer PM, Klee CB. Dual calcium ion regulation of calcineurin by calmodulin and calcineurin B. Biochemistry 1994; 33:6859-66. [PMID: 8204620 DOI: 10.1021/bi00188a015] [Citation(s) in RCA: 206] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The dependence of calcineurin on Ca2+ for activity is the result of the concerted action of calmodulin, which increases the turnover rate of the enzyme and modulates its response to Ca2+ transients, and of calcineurin B, which decreases the Km of the enzyme for its substrate. The calmodulin-stimulated protein phosphatase calcineurin is under the control of two functionally distinct, but structurally similar, Ca(2+)-regulated proteins, calmodulin and calcineurin B. The Ca(2+)-dependent activation of calcineurin by calmodulin is highly cooperative (Hill coefficient of 2.8-3), and the concentration of Ca2+ needed for half-maximum activation decreases from 1.3 to 0.6 microM when the concentration of calmodulin is increased from 0.03 to 20 microM. Conversely, the affinity of calmodulin for Ca2+ is increased by more than 2 orders of magnitude in the presence of a peptide corresponding to the calmodulin-binding domain of calcineurin A. Calmodulin increases the Vmax without changing the Km value of the enzyme. Unlike calmodulin, calcineurin B interacts with calcineurin A in the presence of EGTA, and Ca2+ binding to calcineurin B stimulates native calcineurin up to only 10% of the maximum activity achieved with calmodulin. The Ca(2+)-dependent activation of a proteolyzed derivative of calcineurin, calcineurin-45, which lacks the regulatory domain, was used to study the role of calcineurin B. Removal of the regulatory domain increases the Vmax of calcineurin, as does binding of calmodulin, but it also increases the affinity of calcineurin for Ca2+. Ca2+ binding to calcineurin B decreases the Km value of calcineurin without changing its Vmax.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P M Stemmer
- Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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30
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Huang S, Carlson G, Cheung W. Calmodulin-dependent enzymes undergo a protein-induced conformational change that is associated with their interactions with calmodulin. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37334-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Nargang CE, Bottorff DA, Adachi K. Isolation and characterization of a cDNA clone coding for the calcium-binding subunit of calcineurin from bovine brain: an identical amino acid sequence to the human protein. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 1994; 4:313-8. [PMID: 7803816 DOI: 10.3109/10425179409020857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A cDNA clone encoding the calcium-binding subunit of calcineurin, calcineurin B, was isolated from a bovine brain library by immunoscreening. The 841 bp cDNA has a 56 bp 5'-noncoding region, an open reading frame of 510 bp, and a 275 bp 3'-noncoding sequence. The deduced amino acid sequence of bovine calcineurin B differs from the previously reported protein sequence (Aitken et al., 1984) by three residues. The sequence contained additional valine at the carboxyl terminus and substitutions of Met-11 and Ser-153 (the positions according to Aitken et al., 1984) by cysteine. The amino acid sequence of bovine calcineurin B was found to be identical to that of human calcineurin B sequence (Guerini et al., 1989). In fact, 97.1% homology was observed between the coding regions of human and bovine calcineurin B. In addition, a very high homology of 95.2% was observed for the 3'-noncoding region while the 5'-noncoding region showed 58.9% homology. The beta-galactosidase fusion protein, having the apparent molecular weight of 29 kDa, was detected on Western blots by subunit B-specific monoclonal antibody (Matsui et al., 1985). Northern analysis revealed that there is a single calcineurin B transcript in bovine brain which is 2.3 kb in length. This is in agreement with the observation of only one immunologically detectable subunit B protein in bovine brain (Matsui et al., 1985).
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Affiliation(s)
- C E Nargang
- Department of Oral Biology, University of Alberta, Edmonton, Canada
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32
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Clipstone NA, Crabtree GR. Calcineurin is a key signaling enzyme in T lymphocyte activation and the target of the immunosuppressive drugs cyclosporin A and FK506. Ann N Y Acad Sci 1993; 696:20-30. [PMID: 7509131 DOI: 10.1111/j.1749-6632.1993.tb17138.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- N A Clipstone
- Howard Hughes Medical Institute, Stanford University School of Medicine, California 94305
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33
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Ueki K, Kincaid R. Interchangeable associations of calcineurin regulatory subunit isoforms with mammalian and fungal catalytic subunits. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53286-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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34
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Haddy A, Swanson SK, Born TL, Rusnak F. Inhibition of calcineurin by cyclosporin A-cyclophilin requires calcineurin B. FEBS Lett 1992; 314:37-40. [PMID: 1333415 DOI: 10.1016/0014-5793(92)81456-v] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The interaction of the immunosuppressive complex cyclosporin A-cyclophilin (CsA-CyP) with the Ca2+/calmodulin-dependent protein phosphatase calcineurin is investigated using a recombinant form of the A subunit of calcineurin (rCNA). Only in the presence of purified calcineurin B (CNB) does rCNA show the response of native calcineurin, i.e. 50% inhibition of rCNA phosphatase activity at 6 nM human cyclophilin B and 0.6 microM human cyclophilin A using [32P]casein as substrate, yet stimulation of activity with p-nitrophenyl phosphate as substrate. This study demonstrates that the B subunit is necessary to confer sensitivity of calcineurin to CsA-CyP.
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Affiliation(s)
- A Haddy
- Section of Hematology Research, Mayo Foundation, Rochester, MN 55905
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35
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Guerini D, Montell C, Klee C. Molecular cloning and characterization of the genes encoding the two subunits of Drosophila melanogaster calcineurin. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41706-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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36
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Hu ZY, Gong YS, Huang WL. Interaction of berbamine compound E6 and calmodulin-dependent myosin light chain kinase. Biochem Pharmacol 1992; 44:1543-7. [PMID: 1417979 DOI: 10.1016/0006-2952(92)90470-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The interaction of the berbamine compound E6 and calmodulin (CaM)-dependent myosin light chain kinase (MLCK) has been studied. The experimental results showed that the inhibition of MLCK activity was increased with increasing amounts of E6 and was overcome completely by the addition of excessive CaM. The stimulatory activity of MLCK induced by CaM was gradually inhibited by the increasing concentrations of compound E6, showing that the inhibition of MLCK activity by compound E6 was concentration dependent; and the Ki was 0.95 microM. Compound E6 diminished the fluorescence intensity of dansyl-labeled CaM and the intensity was increased gradually by the addition of different amounts of CaM. Compound E6 had no effect on the activity of MLCK fragments produced by limited trypsinization, and it is a novel and considerably potent calmodulin antagonist.
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Affiliation(s)
- Z Y Hu
- Division of Biochemistry, China Pharmaceutical University, Nanjing, Jiangsu
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37
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Characterization of the phosphatase activity of a baculovirus-expressed calcineurin A isoform. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)49628-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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38
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Clipstone NA, Crabtree GR. Identification of calcineurin as a key signalling enzyme in T-lymphocyte activation. Nature 1992; 357:695-7. [PMID: 1377362 DOI: 10.1038/357695a0] [Citation(s) in RCA: 1269] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The immunosuppressive drugs cyclosporin A (CsA) and FK506 both interfere with a Ca(2+)-sensitive T-cell signal transduction pathway, thereby preventing the activation of specific transcription factors (such as NF-AT and NF-IL2A) involved in lymphokine gene expression. CsA and FK506 seem to act by interaction with their cognate intracellular receptors, cyclophilin and FKBP, respectively (see ref. 11 for review). The Ca2+/calmodulin-regulated phosphatase calcineurin is a major target of drug-isomerase complexes in vitro. We have therefore tested the hypothesis that this interaction is responsible for the in vivo effects of CsA/FK506. We report here that overexpression of calcineurin in Jurkat cells renders them more resistant to the effects of CsA and FK506 and augments both NFAT- and NFIL2A-dependent transcription. These results identify calcineurin as a key enzyme in the T-cell signal transduction cascade and provide biological evidence to support the notion that the interaction of drug-isomerase complexes with calcineurin underlies the molecular basis of CsA/FK506-mediated immunosuppression.
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Affiliation(s)
- N A Clipstone
- Beckman Center for Molecular and Genetic Medicine, Howard Hughes Medical Institute, Stanford University School of Medicine, California 94305
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39
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Sakane F, Imai S, Yamada K, Kanoh H. The regulatory role of EF-hand motifs of pig 80K diacylglycerol kinase as assessed using truncation and deletion mutants. Biochem Biophys Res Commun 1991; 181:1015-21. [PMID: 1662491 DOI: 10.1016/0006-291x(91)92038-l] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To elucidate the regulatory function of EF-hand motifs of pig 80K diacylglycerol (DG) kinase, we constructed and expressed several truncation and deletion mutants of the enzyme in E. coli or COS-7 cells. The bacterially expressed EF-hand region could bind Ca2+ and was suggested to undergo conformational change like calmodulin. A mutant enzyme lacking EF-hands lost Ca(2+)-binding activity, but could be fully activated by phosphatidylserine (PS) or deoxycholate in the absence of Ca2+. The full activation of the wild-type enzyme by PS, on the other hand, was totally dependent on Ca2+. Further, the wild-type enzyme expressed in COS-7 cells was exclusively soluble, whereas the EF-hand-deleted mutant was considerably associated with the membranes. The results suggest that under Ca(2+)-free condition, the EF-hand masks the PS-binding site of the DG kinase, and that the Ca(2+)-binding results in the exposure of the PS-binding site through the conformational change of the EF-hand region.
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Affiliation(s)
- F Sakane
- Department of Biochemistry, Sapporo Medical College, Japan
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40
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Higuchi S, Tamura J, Giri P, Polli J, Kincaid R. Calmodulin-dependent protein phosphatase from Neurospora crassa. Molecular cloning and expression of recombinant catalytic subunit. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)55242-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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41
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Abstract
The cloning and sequence determination of cDNAs encoding different types of serine/threonine protein phosphatases has provided a molecular basis for the protein phosphatase classification proposed by Ingebritsen and Cohen. Each of the phosphatases, phosphatase-1, -2A, -2B and -2C, exists as multiple isozymes raising the possibility that isozymes selectively expressed in different tissues may perform specific functions. The recent discovery of potent toxin inhibitors specific for protein phosphatase-1 and -2A will undoubtedly play an important role in the elucidation of the role of these enzymes in neuronal function.
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Affiliation(s)
- P Stemmer
- Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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42
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Richard M, Broquet P, Vignon E, Peschard MJ, Carret JP, Louisot P. Calmodulin-dependent collagenase and proteoglycanase activities in chondrocytes from human osteoarthritic cartilage. Biochem Biophys Res Commun 1991; 174:1204-7. [PMID: 1847628 DOI: 10.1016/0006-291x(91)91549-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chondrocyte metalloproteinases appear to play a major role in the development of osteoarthritis. The intracellular post-traductional mechanisms regulating collagenase and proteoglycanase are not known. Calmodulin antagonists including phenothiazine and sulfonamide derivatives significantly increased proteoglycanase activity and decreased collagenase activity. H-7, a specific inhibitor of protein kinase C, had no effect on the two metalloproteinase activities, and calmodulin was ineffective in in vitro assays upon metalloproteinase activities. We postulate that collagenase and proteoglycanase activities are controlled by calmodulin-dependent regulation.
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Affiliation(s)
- M Richard
- Department of General and Medical Biochemistry INSERM-CNRS U189 Lyon-Sud Medical School Oullins, France
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43
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Kincaid RL, Giri PR, Higuchi S, Tamura J, Dixon SC, Marietta CA, Amorese DA, Martin BM. Cloning and characterization of molecular isoforms of the catalytic subunit of calcineurin using nonisotopic methods. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38593-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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44
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Hubbard MJ, Klee CB. Characterization of a high-affinity monoclonal antibody to calcineurin whose epitope defines a new structural domain of calcineurin A. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 185:411-8. [PMID: 2479557 DOI: 10.1111/j.1432-1033.1989.tb15130.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Monoclonal antibodies have been raised against native calcineurin using conventional in vivo immunization and hybridoma procedures. The relatively high affinity of nonimmune IgG for the two subunits of calcineurin resulted in large nonspecific binding values for immunoassays of native, dissociated and denatured calcineurin, which complicated the antibody screening. Monoclonal aCn5, a high-affinity IgG1 that exhibits specific binding, was characterized. Other calmodulin-binding proteins tested were not recognized by aCn5. Simple binding properties were exhibited in solid-phase experiments, Kd = 26 (+/- 4) pM, but the stoichiometry was low. The loss of immunoreactivity after denaturation of calcineurin indicated that the aCn5 epitope is of the assembled topographic, not segmental, type. The epitope was located to the A subunit and affinity was unaffected by the presence of calcineurin B. The epitope remained intact after proteolytic removal of the amino-terminal 20 residues of calcineurin A essential for phosphatase activity, and the carboxyl-terminal inhibitory and calmodulin-binding domains. The calmodulin-binding peptide derived from calcineurin, cA8, was not recognized by aCn5. Addition of Ca2+, Mn2+, Ni2+, chelators or dithiothreitol did not influence the affinity of aCn5 for the holoenzyme. Phosphatase activity of calcineurin, in the presence and absence of calmodulin and after removal of the inhibitory domain, was little affected by aCn5. Thus, the aCn5 epitope defines a previously unidentified structural domain of calcineurin A located in a region of the proteolytically resistant core that is topologically distinct from the catalytic, inhibitory, calmodulin-binding and calcineurin-B-binding domains, and not functionally connected with calcineurin B or the putative metal-binding domain(s).
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Affiliation(s)
- M J Hubbard
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, MD 20892
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45
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Guerini D, Krinks MH, Sikela JM, Hahn WE, Klee CB. Isolation and sequence of a cDNA clone for human calcineurin B, the Ca2+-binding subunit of the Ca2+/calmodulin-stimulated protein phosphatase. DNA (MARY ANN LIEBERT, INC.) 1989; 8:675-82. [PMID: 2558868 DOI: 10.1089/dna.1.1989.8.675] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have identified and cloned human cDNA for the Ca2+-binding subunit of calcineurin, the brain isozyme of the Ca2+/calmodulin-stimulated protein phosphatase. The 2.5-kb cDNA has an open reading frame of 510 bp, a leader sequence of at least 500 bp, and a 1,277-bp 3'-noncoding sequence. The deduced sequence of the human protein differs from bovine brain calcineurin B by an additional valine at the carboxyl terminus and substitution of Met-11 and Ser-153 by cysteine. A partial clone of the mouse protein corresponding to amino acids 75-150 was also isolated. This portion of the human and mouse protein sequence is identical, with the DNA sequences showing 94% identity. The respective mRNAs in human and mouse are also of similar size. As was observed with protein levels, mRNA abundance in brain is 20-60 times that found in other tissues with the exception of HeLa cells which, like brain, contain abundant calcineurin B mRNA.
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Affiliation(s)
- D Guerini
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, MD 20892
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46
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Huang SL, Merat D, Cheung WY. Phosphatidylinositol modulates the response of calmodulin-dependent phosphatase to calmodulin. Arch Biochem Biophys 1989; 270:42-9. [PMID: 2539050 DOI: 10.1016/0003-9861(89)90005-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Phosphatidylinositol (PtdIns) and many other phospholipids activated calmodulin (CaM)-dependent phosphatase in the presence or absence of Ca2+, and the stimulation was more pronounced in the presence of Ca2+. In addition, PtdIns modulated the response of phosphatase to CaM: at low and nonstimulatory concentrations (less than 70 microM), PtdIns augmented the activity of phosphatase by a submaximum concentration of CaM, giving a synergistic effect; and at high concentrations (greater than 100 microM), PtdIns suppressed the synergistic effect. Kinetic experiments indicated that PtdIns (both nonstimulatory and stimulatory concentrations) increased the affinity of phosphatase for CaM. In addition to the CaM regulatory site, phosphatase appears to have two PtdIns regulatory sites: a high-affinity site the occupation of which does not stimulate enzyme activity, and a low-affinity site the occupation of which stimulates enzyme activity in the absence of CaM and inhibits it in the presence of CaM. Modulating the response of phosphatase to CaM is not unique to PtdIns, and was observed with other phospholipids, including some that did not stimulate the enzyme. This raises the possibility that certain phospholipids may regulate phosphatase in two ways: (i) direct activation of the enzyme and (ii) modulation of its response to CaM.
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Affiliation(s)
- S L Huang
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38101
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47
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Armstrong DL. Calcium channel regulation by calcineurin, a Ca2+-activated phosphatase in mammalian brain. Trends Neurosci 1989; 12:117-22. [PMID: 2469218 DOI: 10.1016/0166-2236(89)90168-9] [Citation(s) in RCA: 148] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The enzymatic addition or removal of phosphate esters on serine and threonine hydroxyls alters the activity of many proteins that contribute to the characteristic structure and function of nerve cells. Recently, calcineurin, a major calmodulin-binding protein in mammalian brain, has been purified and identified as a Ca2+-activated protein phosphatase. Preliminary experiments suggest that calcineurin may limit Ca2+ influx through dihydropyridine-sensitive Ca2+ channels in the plasma membrane by dephosphorylating the channel, or a closely associated protein, and inactivating it.
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48
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Pezzi L, Merat DL, Winkler MA, Cheung WY. Calmodulin-dependent phosphatase preferentially dephosphorylates a 28 kDa protein in human platelets. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1989; 21:791-8. [PMID: 2547673 DOI: 10.1016/0020-711x(89)90212-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. Human platelets contain a calmodulin-dependent phosphatase (calcineurin) that has many properties similar to those of bovine brain calmodulin-dependent phosphatase. 2. The activity of calcineurin phosphatase accounts for a small fraction of the total phosphatase activity in human platelets. 3. Labeling of human platelets with 32P yielded many phosphoproteins. 4. Incubation of a lysate of the 32P-labeled platelets with bovine brain calmodulin-dependent phosphatase led to preferential dephosphorylation of a 28 kDa protein (P28), a minor component of platelet proteins. 5. P28 is one of several proteins that were rapidly labeled upon stimulation of platelets with thrombin. 6. Even though the enzyme is known to catalyze the dephosphorylation of many substrates in vitro, its apparent preference for P28 suggests that its activity is highly selective.
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Affiliation(s)
- L Pezzi
- Department of Biochemistry, St Jude Children's Research Hospital, Memphis, TN 38101
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Kincaid RL, Martin BM. Characterization of the calmodulin-binding domain of calcineurin deduced from a complementary DNA clone. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1989; 255:347-58. [PMID: 2559598 DOI: 10.1007/978-1-4684-5679-0_38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- R L Kincaid
- Section on Immunology, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD 20892
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Stewart AA, Cohen P. Protein phosphatase-2B from rabbit skeletal muscle: a Ca2+-dependent, calmodulin-stimulated enzyme. Methods Enzymol 1988; 159:409-16. [PMID: 2842605 DOI: 10.1016/0076-6879(88)59040-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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