Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.16 (calcineurin)
17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have shown that an acidic phosphoprotein phosphatase (APP-ase) has a different pattern of postnatal maturation in the spleen, thymus and liver of rats and mice. The APP-ase activity increases during the first eight months of postnatal life in the spleen of rats (when it attains an 8--10 times higher value than at birth) and up to the sixth month of life in the spleen of mice. It increases considerably during the first two weeks of postnatal life in the thymus of rats and mice; in the liver of rats it reaches maximum activity before birth, but continues to increase up to the sixth month of postnatal life in the liver of mice. The results show also that the APP-ase from the spleen, thymus and liver of rats is equally active in dephosphorylating ATP and phenyl phosphate during the whole life span of rats, but not in relation to beta-glycerol phosphate. After analyzing its substrate specificity, its pH dependence in relation to different substrates, its kinetic properties, as well as its behaviour towards ascorbic acid and different inhibitors (sodium tungstate and sodium molybdate, L-tartrate, L-phenylalanine and L-cysteine) we have come to the conclusion that the rat spleen APP-ase is different from "nonspecific" acid and alkaline phosphatases and very similar to the EC 3.1.3.16 acid phosphoprotein phosphatase.
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PMID:The ontogenetic evolution of acidic phosphoprotein phosphatase activity in the lymphatic tissue and the liver of the rat. 21 22

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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PMID:Isolation and sequence of a cDNA clone for human calcineurin B, the Ca2+-binding subunit of the Ca2+/calmodulin-stimulated protein phosphatase. 255 68

The complete amino acid sequence of bovine brain DARPP-32, a dopamine- and cyclic AMP-regulated neuronal phosphoprotein, which is a potent and specific inhibitor of the catalytic subunit of protein phosphatase-1, has been determined. The S-14C-carboxymethylated protein was subjected to enzymatic cleavage by endoproteinase Lys-C, endoproteinase Arg-C, trypsin, chymotrypsin, and Staphylococcus aureus V8 protease, and to chemical cleavage by cyanogen bromide. The overlapping sets of peptides were purified by high performance liquid chromatography and subjected to amino acid sequencing by automated Edman degradation to deduce the complete sequence. The protein consists of a single NH2-terminal blocked polypeptide chain of 202 residues, with a calculated molecular mass of 22,591 daltons, excluding the unidentified NH2-terminal blocking group. This molecular mass is significantly lower than earlier estimates based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis or hydrodynamic measurements. The threonine residue that is phosphorylated by cyclic AMP-dependent protein kinase (Hemmings, H. C., Jr., Williams, K. R., Konigsberg, W. H., and Greengard, P. (1984) J. Biol. Chem. 259, 14486-14490), and that must be phosphorylated for the expression of inhibitory activity, is located at position 34. The molecule contains only 1 cysteine residue and 1 tryptophan residue, at positions 72 and 161, respectively. DARPP-32 is very hydrophilic, and contains a stretch of 16 consecutive acidic residues from position 119 to 134. The predicted secondary structure suggests the presence of 47% alpha-helix, 7% beta-sheet, and 46% random coil, with 11 beta-turns. Comparison of the complete amino acid sequence of bovine DARPP-32 with that of rabbit skeletal muscle protein phosphatase inhibitor-1 revealed a significant amount of sequence identity in the NH2-terminal regions of these two proteins. The active region of inhibitor-1 has been localized to an NH2-terminal fragment (Aitken, A., and Cohen, P. (1982) FEBS Lett. 147, 54-58), the part of the molecule that is most similar to DARPP-32. These data suggest that these two protein phosphatase inhibitors may share a common structural basis for their inhibitory activity and may be related by a common ancestral gene.
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PMID:DARPP-32, a dopamine- and cyclic AMP-regulated neuronal phosphoprotein. Primary structure and homology with protein phosphatase inhibitor-1. 351 Oct 54

The complete primary structure of inhibitor-2, a specific inhibitor of protein phosphatase-1, has been determined. The protein consists of a single polypeptide chain of 203 residues, and has a relative molecular mass of 22835 Da. This molecular mass is significantly lower than earlier estimates based on sodium dodecyl sulphate polyacrylamide gel electrophoresis. The threonyl residue phosphorylated by glycogen synthase kinase-3 is located at position 72. The molecule is very hydrophilic, lacks cysteine residues and the single tryptophanyl and phenylalanyl residues are at positions 46 and 139, respectively. The N-terminal alanyl residue is N-acetylated. Digestion with Staphylococcus aureus V8 proteinase, trypsin, or cleavage with cyanogen bromide, destroyed the biological activity of inhibitor-2, demonstrating that many large fragments (e.g. 1-49, 49-92, 67-101, 108-134, 142-182 and 163-197) are inactive. Digestion with clostripain generated a peptide comprising residues 25-114 which retained 2% of the inhibitory potency of the parent molecule. There is no sequence homology between inhibitor-2 and inhibitor-1.
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PMID:The protein phosphatases involved in cellular regulation. Primary structure of inhibitor-2 from rabbit skeletal muscle. 351 70

The importance of cysteine residues on the function and regulation of calcineurin was investigated using chemical modification by sulfhydryl reagents. Calcineurin was stable toward incubation with several commonly employed reagents but not toward p-hydroxymercuribenzoic acid and N-ethylmaleimide, which partially inactivated the Ca2+-supported activity and rapidly abolished its activation by Ni2+. Ni2+ provided only slight protection from inactivation by N-ethylmaleimide which argued against labeling of the Ni2+ binding site(s). In contrast, protection was provided by Ca2+; this is probably due to allosteric effects, since Ca2+ binds to the B subunit while the A subunit contains all of the cysteine residues of calcineurin. These results suggest that activation of calcineurin by Ni2+ is synergistic with Ca2+ and indicates an important role for the Ca2+-binding subunit in the activation process. Labeling of calcineurin by [14C]N-ethylmaleimide was biphasic. An initial, rapid phase was without effect on the Ni2+ activity; inactivation correlated with a second, slower phase of modification. Differential labeling in the presence and absence of Ca2+ suggested that inactivation correlates with labeling of two residues. A kinetic analysis of the reaction order indicated that modification of only one of these groups may be responsible for inactivation; thus, 1 cysteine residue on the catalytic subunit appears to be important in establishing the Ni2+-activated conformation of calcineurin.
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PMID:Modification of the calmodulin-stimulated phosphatase, calcineurin, by sulfhydryl reagents. 394 3

The catalytic subunit of phosphoprotein phosphatase (Mr = 35,000) is inactivated by phosphate compounds such as trimetaphosphate, PPi, and ATP. The inactivation of phosphoprotein phosphatase by these phosphate compounds is time- and concentration-dependent, is not reversed by dilution or gel filtration and is protected by Pi. A dissociation constant for the enzyme-trimetaphosphate complex and a rate constant for the reaction were calculated to be 4.6 x 10(-4) M and 0.29 min-1, respectively. The inactivation of phosphatase by PPi and ATP shows more complex kinetics than that by trimetaphosphate. The addition of EDTA to PPi and ATP exhibits more potent inactivation, even though EDTA alone does not inactivate phosphatase. This phosphoprotein phosphatase is not labeled by [gamma-32P]ATP. The inactivation of phosphatase by PPi or ATP can only be reversed by Mn2+ or Co2+, among all other metals or cationic compounds tried. The reactivation also requires sulfhydryl compounds. The effectiveness of sulfhydryl compounds follows the order: dithioerythritol greater than mercaptoethanol greater than cysteine. Glutathione was without effect. Metal analysis of the catalytic subunit did not reveal any significant amounts of Ca, Cd, Co, Cu, Fe, Mg, Mn, Ni, Sn, or Zn. Phosphoprotein phosphatase activity from zinc-deficient rat livers also eliminated the possibility of this phosphatase being a zinc metalloenzyme. Inactivation does not seem to be due to a loss of a critical metal ion. Other mechanisms for inactivation are presented.
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PMID:Inactivation and reactivation of phosphoprotein phosphatase. 627 82

The crystal structures of a cysteine-215-->serine mutant of protein tyrosine phosphatase 1B complexed with high-affinity peptide substrates corresponding to an autophosphorylation site of the epidermal growth factor receptor were determined. Peptide binding to the protein phosphatase was accompanied by a conformational change of a surface loop that created a phosphotyrosine recognition pocket and induced a catalytically competent form of the enzyme. The phosphotyrosine side chain is buried within the period and anchors the peptide substrate to its binding site. Hydrogen bonds between peptide main-chain atoms and the protein contribute to binding affinity, and specific interactions of acidic residues of the peptide with basic residues on the surface of the enzyme confer sequence specificity.
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PMID:Structural basis for phosphotyrosine peptide recognition by protein tyrosine phosphatase 1B. 754 Jul 71

The compound 4-(fluoromethyl)phenyl phosphate (FMPP), recently shown to be a mechanism-based inhibitor of prostatic acid phosphatase (Myers, J.K., and Widlanski, T.S. (1993) Science 262, 1451-1453), was examined for its effect on calcineurin. This compound inhibits calcineurin in a time-dependent, first order manner. Inactivation with [3H]FMPP led to a specific labeling of the catalytic subunit with a stoichiometry of 0.75 mol of label/mol of protein. A related substrate, 4-methylphenyl phosphate, is able to protect calcineurin from FMPP-mediated inhibition. Scavenging nucleophiles, such as cysteine, do not affect the rate of inhibition when included in the reaction. In addition, extensive dialysis indicates that inhibition is essentially irreversible. These results demonstrate that FMPP inactivates calcineurin in a mechanism-based fashion by forming a covalent adduct with calcineurin A, the catalytic subunit.
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PMID:4-(Fluoromethyl)phenyl phosphate acts as a mechanism-based inhibitor of calcineurin. 759 41

Polyomavirus middle T antigen (MT) interacts with several cellular proteins involved in cell proliferation. MT forms complexes with protein phosphatase 2A (PP2A), pp60c-src (and the related kinases c-fyn and c-yes), and phosphatidylinositol-3 kinase. We made a single point mutation in MT, changing a conserved cysteine residue at position 120 to tryptophan, and characterized the biochemical and biological properties of the mutant (C120W) protein. The mutant MT protein does not associate with PP2A, pp60c-src, or phosphatidylinositol-3 kinase as judged by coimmunoprecipitation and associated phosphatase or kinase activity. The C120W mutant is defective in activation of c-fos expression and in morphological transformation of NIH 3T3 cells.
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PMID:Mutation of a cysteine residue in polyomavirus middle T antigen abolishes interactions with protein phosphatase 2A, pp60c-src, and phosphatidylinositol-3 kinase, activation of c-fos expression, and cellular transformation. 768 Mar 88

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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PMID: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. 780 16


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