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)

Calcineurin is one of the calmodulin binding proteins and a Ca2+-dependent and calmodulin-stimulated phosphoprotein phosphatase. We used antisera to the calcineurin as a cell-type-specific marker in order to identify neuronal cells in the rat brain and human neoplasms. In normal rat brain slices, basal ganglia were stained macroscopically, and other areas such as cerebral cortex, corpus callosum, cerebellar cortex, granular layer and pyramidal tract of the spinal cord were lightly identified as well. Under the light microscope, it was found that only the neuronal cells were stained, and astrocytes, oligodendrocytes, ependymal cells and vessels were not. Intracellular distribution of the staining showed various patterns and staining intensity of varying degree. Using the PAP method, localization of the calcineurin in formalin-fixed, paraffin-embedded tissues were studied in 65 human intracranial neoplasms, and in 11 human extracranial neoplasms. The neuronal elements of neuroblastoma, ganglioglioma, ganglioneuroma and retinoblastoma were clearly stained. In contrast, glioblastoma, astrocytoma, oligodendroglioma, ependymoma, meningioma, neurinoma, pituitary adenoma, craniopharyngioma, hemangioblastoma, hamartoma, lymphoma and mesenchymal tumor were all negative. Two cases out of 5 medulloblastomas were stained, but others were not. Although positive tumors disclosed various staining patterns and intensities, these results indicated that calcineurin could be a new neuronal marker in human brain tumors.
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PMID:Calcineurin as a neuronal marker of human brain tumors. 242 51

Calmodulin-dependent phosphoprotein phosphatase (CaMDP) activity has been found in each of three cultured cell lines: rat pheochromocytoma (PC12), glioma (C6), and pituitary adenoma (GH3) cells. These CaMDP activities bind to immobilized calmodulin in the presence of Ca2+ and are eluted by EGTA. Sucrose density centrifugation revealed that the phosphatase activities exhibited sedimentation coefficients of 4.37, 4.23, and 4.59 for proteins derived from C6, GH3, and PC12 cells, respectively. The Stokes radii measured for the PC12 and C6 activities were 41.8 and 40.0 A, respectively. The estimated molecular weights calculated for the enzymes from these data are 79,100 and 72,200. The phosphatase activities required the presence of divalent cations such as Ca2+ or Mn2+ for expression of activity, which was optimal only in the presence of calmodulin. The apparent Km for phosphorylated myelin basic protein substrate was 8 microM. Affinity-purified antibodies to the B subunit of bovine brain CaMDP were found by immunoblot (Western blot) to cross-react with a single protein among proteins extracted from PC12, C6, and GH3 cells that had been resolved by two-dimensional electrophoresis. In each case, the cross-reacting protein exhibited an Mr of 16,000 and an isoelectric point of 4.7, values virtually identical to those reported previously for the B subunit of bovine brain CaMDP (sometimes called calcineurin). This cross-reacting protein was found among cellular proteins eluted from immobilized calmodulin by EGTA. Immunocytochemical localization of the cross-reacting protein in undifferentiated PC12 cells or in cells differentiated in response to nerve growth factor revealed its presence diffusely throughout the cytoplasm. These experiments support the contention that each of these cell lines contains a calmodulin-regulated phosphatase homologous physically and kinetically, and immunologically related to bovine brain CaMDP.
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PMID:Calmodulin-dependent phosphatases of PC12, GH3, and C6 cells: physical, kinetic, and immunochemical properties. 329 45