Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.

  • Authors:
    • T Hamano
    • M Yamaguchi
  • View Affiliations

  • Published online on: June 1, 1999     https://doi.org/10.3892/ijmm.3.6.615
  • Pages: 615-624
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Abstract

The effect of Ca2+-binding protein regucalcin on neutral phosphatase activity in rat brain cytosol was investigated. Phosphatase activity was assayed in a reaction mixture containing the cytosolic protein in the presence of phosphotyrosine, phosphoserine, and phosphothreonine. The presence of calcium chloride (10(-5) and 10(-4) M) in the enzyme reaction mixture caused a significant increase in phosphatase activity toward three phosphoaminoacids. The enzyme activity toward phosphoserine and phosphothreonine was significantly enhanced by the addition of calmodulin (1 or 5 microg/ml) in the presence of calcium (10(-5) M). Such an effect was not seen in the presence of phosphotyrosine. Trifluoperazine (2x10(-5) M), an antagonist of calmodulin, completely inhibited calcium (10(-5) M)-increased phosphatase activity toward phosphoserine and phosphothreonine, whereas it had no effect on the enzyme activity toward phosphotyrosine. Regucalcin (10(-9) M) significantly inhibited phosphatase activity toward three phosphoaminoacids without or with Ca2+ addition. The inhibitory effect of regucalcin (10(-10) and 10(-9) M) was also seen in the presence of Ca2+ (10(-5) M) and calmodulin (5 microg/ml). The presence of anti-regucalcin monoclonal antibody (20 or 50 ng/ml) in the enzyme reaction mixture caused a significant elevation of phosphatase activity toward three phosphoaminoacids; this effect was completely abolished by addition of regucalcin (10(-9) M). The present study suggests that the endogenous regucalcin has an inhibitory effect on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.

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Jun 1999
Volume 3 Issue 6

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Hamano T and Yamaguchi M: Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.. Int J Mol Med 3: 615-624, 1999.
APA
Hamano, T., & Yamaguchi, M. (1999). Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.. International Journal of Molecular Medicine, 3, 615-624. https://doi.org/10.3892/ijmm.3.6.615
MLA
Hamano, T., Yamaguchi, M."Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.". International Journal of Molecular Medicine 3.6 (1999): 615-624.
Chicago
Hamano, T., Yamaguchi, M."Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.". International Journal of Molecular Medicine 3, no. 6 (1999): 615-624. https://doi.org/10.3892/ijmm.3.6.615