 |
Previous Article | Next Article 
Volume 17, Number 22,
Issue of November 15, 1997
pp. 8676-8686
Ca2+ Influx Amplifies Protein Kinase C Potentiation
of Recombinant NMDA Receptors
Received June 4, 1997; revised Aug. 18, 1997; accepted Aug 26, 1997.
Xin Zheng,
Ling Zhang,
Alice P. Wang,
Michael V. L. Bennett, and
R. Suzanne Zukin
Department of Neuroscience, Albert Einstein College of Medicine,
Bronx, New York 10461
Protein kinase C (PKC) potentiates NMDA receptors in hippocampal,
trigeminal, and spinal neurons. Although PKC phosphorylates the NMDA
receptor subunit NR1 at four residues within the C terminal splice
cassette C1, the molecular mechanisms underlying PKC
potentiation of NMDA responses are not yet known. The present study
examined the role of Ca2+ in PKC potentiation of
recombinant NMDA receptors expressed in Xenopus oocytes.
We found that Ca2+ influx through PKC-potentiated
NMDA receptors can further increase the NMDA response
("Ca2+ amplification"). Ca2+
amplification required a rise in intracellular Ca2+
concentration at or near the intracellular end of the channel and was
independent of Ca2+-activated
Cl current. Ca2+ amplification
depended on extracellular Ca2+ concentration during
NMDA application and not during PKC activation. Ca2+
amplification was reduced by the membrane-permeant
Ca2+-chelating agent BAPTA-AM. Mutant receptors with
greatly reduced Ca2+ permeability did not exhibit
Ca2+ amplification. Receptors containing the NR1
N-terminal splice cassette showed more Ca2+
amplification, possibly because of their larger basal current and
therefore greater Ca2+ influx. Contrary to
expectation, splicing out the two C-terminal splice cassettes of NR1
enhanced PKC potentiation in a manner independent of extracellular
Ca2+. This observation indicates that PKC
potentiation does not require phosphorylation of the C1
cassette of the NR1 subunit. PKC potentiation of NMDA receptors
in vivo is likely to be affected by
Ca2+ amplification of the potentiated signal; the
degree of amplification will depend in part on alternative splicing of
the NR1 subunit, which is regulated developmentally and in a
cell-specific manner.
Key words:
protein kinase C;
NMDA receptors;
alternative RNA
splicing;
TPA;
BAPTA;
Xenopus oocyte
This article has been cited by other articles:

|
 |

|
 |
 
H. Sun, X.-Q. Hu, E. M. Moradel, F. F. Weight, and L. Zhang
Modulation of 5-HT3 Receptor-mediated Response and Trafficking by Activation of Protein Kinase C
J. Biol. Chem.,
September 5, 2003;
278(36):
34150 - 34157.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J.-y. Lan, V. A. Skeberdis, T. Jover, X. Zheng, M. V. L. Bennett, and R. S. Zukin
Activation of Metabotropic Glutamate Receptor 1 Accelerates NMDA Receptor Trafficking
J. Neurosci.,
August 15, 2001;
21(16):
6058 - 6068.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
V. A. Skeberdis, J.-y. Lan, X. Zheng, R. S. Zukin, and M. V. L. Bennett
Insulin promotes rapid delivery of N-methyl-D- aspartate receptors to the cell surface by exocytosis
PNAS,
March 13, 2001;
98(6):
3561 - 3566.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. RON, A. J. VAGTS, D. P. DOHRMAN, R. YAKA, Z. JIANG, L. YAO, J. CRABBE, J. E. GRISEL, and I. DIAMOND
Uncoupling of {beta}IIPKC from its targeting protein RACK1 in response to ethanol in cultured cells and mouse brain
FASEB J,
November 1, 2000;
14(14):
2303 - 2314.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
X. Zheng, L. Zhang, A. P. Wang, M. V. L. Bennett, and R. S. Zukin
Protein kinase C potentiation of N-methyl-D-aspartate receptor activity is not mediated by phosphorylation of N-methyl-D-aspartate receptor subunits
PNAS,
December 21, 1999;
96(26):
15262 - 15267.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. M. Logan, F. E. Rivera, and J. P. Leonard
Protein Kinase C Modulation of Recombinant NMDA Receptor Currents: Roles for the C-Terminal C1 Exon and Calcium Ions
J. Neurosci.,
February 1, 1999;
19(3):
974 - 986.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
E. D'Angelo, P. Rossi, S. Armano, and V. Taglietti
Evidence for NMDA and mGlu Receptor-Dependent Long-Term Potentiation of Mossy Fiber-Granule Cell Transmission in Rat Cerebellum
J Neurophysiol,
January 1, 1999;
81(1):
277 - 287.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Z.-G. Xiong, R. Raouf, W.-Y. Lu, L.-Y. Wang, B. A. Orser, E. M. Dudek, M. D. Browning, and J. F. MacDonald
Regulation of N-Methyl-D-Aspartate Receptor Function by Constitutively Active Protein Kinase C
Mol. Pharmacol.,
December 1, 1998;
54(6):
1055 - 1063.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
D. Bottai, L. Maler, and R. J. Dunn
Alternative RNA Splicing of the NMDA Receptor NR1 mRNA in the Neurons of the Teleost Electrosensory System
J. Neurosci.,
July 15, 1998;
18(14):
5191 - 5202.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|