A modulatory role for protein phosphatase 2B (calcineurin) in the regulation of Ca2+ entry.
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| Title: | A modulatory role for protein phosphatase 2B (calcineurin) in the regulation of Ca2+ entry. |
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| Authors: | Burley, J. Russell (AUTHOR), Sihra, Talvinder S. (AUTHOR) |
| Source: | European Journal of Neuroscience. Aug2000, Vol. 12 Issue 8, p2881-2891. 11p. 1 Chart. |
| Subjects: | Phosphoprotein phosphatases, Calcium channels, Plasmids, Gene transfection, Physiology |
| Abstract: | AbstractThe Ca2+/calmodulin-dependent protein phosphatase 2B (PP2B) also known as calcineurin (CN) has been implicated in the Ca2+-dependent inactivation of Ca2+ channels in several cell types. To study the role of calcineurin in the regulation of Ca2+-channel activity, phosphatase expression was altered in NG108-15 cells by transfection of sense and antisense plasmid constructs carrying the catalytic subunit of human PP2Bβ3. Relative to mock-transfected (wild-type) controls, cells overexpressing calcineurin showed dramatically reduced high-voltage-activated Ca2+ currents which were recoverable by the inclusion of 1 μm FK506 in the patch pipette. Conversely, in cells with reduced calcineurin expression, high-voltage-activated Ca2+ currents were larger relative to controls. Additionally in these cells, low-voltage-activated currents were significantly reduced. Analysis of high-voltage-activated Ca2+ currents revealed that the kinetics of inactivation were significantly accelerated in cells overexpressing calcineurin. Following the delivery of a train of depolarizing pulses in experiments designed to produce large-scale Ca2+ influx across the cell membrane, Ca2+-dependent inactivation of high-voltage-activated Ca2+ currents was increased in sense cells, and this increase could be reduced by intracellular application of 1 mm BAPTA or 1 μm FK506. These data support a role of calcineurin in the negative feedback regulation of Ca2+ entry through voltage-operated Ca2+ channels. [ABSTRACT FROM AUTHOR] |
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| Database: | Psychology and Behavioral Sciences Collection |
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| Abstract: | AbstractThe Ca2+/calmodulin-dependent protein phosphatase 2B (PP2B) also known as calcineurin (CN) has been implicated in the Ca2+-dependent inactivation of Ca2+ channels in several cell types. To study the role of calcineurin in the regulation of Ca2+-channel activity, phosphatase expression was altered in NG108-15 cells by transfection of sense and antisense plasmid constructs carrying the catalytic subunit of human PP2Bβ3. Relative to mock-transfected (wild-type) controls, cells overexpressing calcineurin showed dramatically reduced high-voltage-activated Ca2+ currents which were recoverable by the inclusion of 1 μm FK506 in the patch pipette. Conversely, in cells with reduced calcineurin expression, high-voltage-activated Ca2+ currents were larger relative to controls. Additionally in these cells, low-voltage-activated currents were significantly reduced. Analysis of high-voltage-activated Ca2+ currents revealed that the kinetics of inactivation were significantly accelerated in cells overexpressing calcineurin. Following the delivery of a train of depolarizing pulses in experiments designed to produce large-scale Ca2+ influx across the cell membrane, Ca2+-dependent inactivation of high-voltage-activated Ca2+ currents was increased in sense cells, and this increase could be reduced by intracellular application of 1 mm BAPTA or 1 μm FK506. These data support a role of calcineurin in the negative feedback regulation of Ca2+ entry through voltage-operated Ca2+ channels. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 0953816X |
| DOI: | 10.1046/j.1460-9568.2000.00178.x |
