Abstract
The N-methyl-D-aspartate (NMDA) receptor NR1 gene encodes RNA that is alternatively spliced to generate at least seven variants. The variants arise from splicing in or out of three exons; one encodes a 21-amino acid insert in the N-terminal domain, and two encode adjacent sequences of 37 and 38 amino acids in the C-terminal domain. Splicing out of the second C-terminal exon deletes a stop codon and results in an additional open reading frame encoding an unrelated sequence of 22 amino acids before arriving at a second stop codon. We denote the NR1 variants by the presence or absence of the three alternatively spliced exons (from 5' to 3'); thus, NR1(111) has all three exons, NR1(000) has none, and NR1(100) has only the N-terminal exon. We report here electrophysiological characterization of six splice variants of the NR1 receptor expressed in Xenopus oocytes. NR1 receptors that lacked the N-terminal exon (NR1(000), NR1(010), and NR1(011)) exhibited a relatively high affinity for NMDA (EC50 approximately 13 microM) and marked potentiation by spermine. In contrast, those receptor variants with the N-terminal insert (NR1(100), NR1(101), and NR1(111)) showed a lower agonist affinity and little or no spermine potentiation at saturating glycine. All six variants showed spermine potentiation at low glycine and inhibition by spermine at more negative potentials. Variants differing only in the C-terminal domain differed little in agonist affinity and spermine potentiation. These findings indicate that the N-terminal insert either participates in agonist and polyamine binding domains or indirectly modifies their conformations. The splice variants differed in the extent to which they could be potentiated by activators of protein kinase C (PKC) from 3- to 20-fold. Presence of the N-terminal insert and absence of the C-terminal sequences increased potentiation by PKC. These findings identify the contributions of the separate polypeptide domains to modulation by polyamines and PKC and provide further support for the concept that subunit composition determines functional properties of NMDA receptors.
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- Anantharam V., Panchal R. G., Wilson A., Kolchine V. V., Treistman S. N., Bayley H. Combinatorial RNA splicing alters the surface charge on the NMDA receptor. FEBS Lett. 1992 Jun 22;305(1):27–30. doi: 10.1016/0014-5793(92)80648-z. [DOI] [PubMed] [Google Scholar]
- Araneda R. C., Zukin R. S., Bennett M. V. Effects of polyamines on NMDA-induced currents in rat hippocampal neurons: a whole-cell and single-channel study. Neurosci Lett. 1993 Apr 2;152(1-2):107–112. doi: 10.1016/0304-3940(93)90495-7. [DOI] [PubMed] [Google Scholar]
- Ben-Ari Y., Aniksztejn L., Bregestovski P. Protein kinase C modulation of NMDA currents: an important link for LTP induction. Trends Neurosci. 1992 Sep;15(9):333–339. doi: 10.1016/0166-2236(92)90049-e. [DOI] [PubMed] [Google Scholar]
- Benveniste M., Clements J., Vyklický L., Jr, Mayer M. L. A kinetic analysis of the modulation of N-methyl-D-aspartic acid receptors by glycine in mouse cultured hippocampal neurones. J Physiol. 1990 Sep;428:333–357. doi: 10.1113/jphysiol.1990.sp018215. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Benveniste M., Mayer M. L. Multiple effects of spermine on N-methyl-D-aspartic acid receptor responses of rat cultured hippocampal neurones. J Physiol. 1993 May;464:131–163. doi: 10.1113/jphysiol.1993.sp019627. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brackley P., Goodnow R., Jr, Nakanishi K., Sudan H. L., Usherwood P. N. Spermine and philanthotoxin potentiate excitatory amino acid responses of Xenopus oocytes injected with rat and chick brain RNA. Neurosci Lett. 1990 Jun 22;114(1):51–56. doi: 10.1016/0304-3940(90)90427-b. [DOI] [PubMed] [Google Scholar]
- Choi D. W. Glutamate neurotoxicity and diseases of the nervous system. Neuron. 1988 Oct;1(8):623–634. doi: 10.1016/0896-6273(88)90162-6. [DOI] [PubMed] [Google Scholar]
- Durand G. M., Gregor P., Zheng X., Bennett M. V., Uhl G. R., Zukin R. S. Cloning of an apparent splice variant of the rat N-methyl-D-aspartate receptor NMDAR1 with altered sensitivity to polyamines and activators of protein kinase C. Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):9359–9363. doi: 10.1073/pnas.89.19.9359. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gerber G., Kangrga I., Ryu P. D., Larew J. S., Randic M. Multiple effects of phorbol esters in the rat spinal dorsal horn. J Neurosci. 1989 Oct;9(10):3606–3617. doi: 10.1523/JNEUROSCI.09-10-03606.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jahr C. E. High probability opening of NMDA receptor channels by L-glutamate. Science. 1992 Jan 24;255(5043):470–472. doi: 10.1126/science.1346477. [DOI] [PubMed] [Google Scholar]
- Kelso S. R., Nelson T. E., Leonard J. P. Protein kinase C-mediated enhancement of NMDA currents by metabotropic glutamate receptors in Xenopus oocytes. J Physiol. 1992 Apr;449:705–718. doi: 10.1113/jphysiol.1992.sp019110. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kushner L., Lerma J., Zukin R. S., Bennett M. V. Coexpression of N-methyl-D-aspartate and phencyclidine receptors in Xenopus oocytes injected with rat brain mRNA. Proc Natl Acad Sci U S A. 1988 May;85(9):3250–3254. doi: 10.1073/pnas.85.9.3250. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kutsuwada T., Kashiwabuchi N., Mori H., Sakimura K., Kushiya E., Araki K., Meguro H., Masaki H., Kumanishi T., Arakawa M. Molecular diversity of the NMDA receptor channel. Nature. 1992 Jul 2;358(6381):36–41. doi: 10.1038/358036a0. [DOI] [PubMed] [Google Scholar]
- Lerma J. Spermine regulates N-methyl-D-aspartate receptor desensitization. Neuron. 1992 Feb;8(2):343–352. doi: 10.1016/0896-6273(92)90300-3. [DOI] [PubMed] [Google Scholar]
- Lerma J., Zukin R. S., Bennett M. V. Glycine decreases desensitization of N-methyl-D-aspartate (NMDA) receptors expressed in Xenopus oocytes and is required for NMDA responses. Proc Natl Acad Sci U S A. 1990 Mar;87(6):2354–2358. doi: 10.1073/pnas.87.6.2354. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lipton S. A., Sucher N. J., Kaiser P. K., Dreyer E. B. Synergistic effects of HIV coat protein and NMDA receptor-mediated neurotoxicity. Neuron. 1991 Jul;7(1):111–118. doi: 10.1016/0896-6273(91)90079-f. [DOI] [PubMed] [Google Scholar]
- McGurk J. F., Bennett M. V., Zukin R. S. Polyamines potentiate responses of N-methyl-D-aspartate receptors expressed in xenopus oocytes. Proc Natl Acad Sci U S A. 1990 Dec;87(24):9971–9974. doi: 10.1073/pnas.87.24.9971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meguro H., Mori H., Araki K., Kushiya E., Kutsuwada T., Yamazaki M., Kumanishi T., Arakawa M., Sakimura K., Mishina M. Functional characterization of a heteromeric NMDA receptor channel expressed from cloned cDNAs. Nature. 1992 May 7;357(6373):70–74. doi: 10.1038/357070a0. [DOI] [PubMed] [Google Scholar]
- Monyer H., Sprengel R., Schoepfer R., Herb A., Higuchi M., Lomeli H., Burnashev N., Sakmann B., Seeburg P. H. Heteromeric NMDA receptors: molecular and functional distinction of subtypes. Science. 1992 May 22;256(5060):1217–1221. doi: 10.1126/science.256.5060.1217. [DOI] [PubMed] [Google Scholar]
- Moriyoshi K., Masu M., Ishii T., Shigemoto R., Mizuno N., Nakanishi S. Molecular cloning and characterization of the rat NMDA receptor. Nature. 1991 Nov 7;354(6348):31–37. doi: 10.1038/354031a0. [DOI] [PubMed] [Google Scholar]
- Nakanishi N., Axel R., Shneider N. A. Alternative splicing generates functionally distinct N-methyl-D-aspartate receptors. Proc Natl Acad Sci U S A. 1992 Sep 15;89(18):8552–8556. doi: 10.1073/pnas.89.18.8552. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nicoll R. A., Kauer J. A., Malenka R. C. The current excitement in long-term potentiation. Neuron. 1988 Apr;1(2):97–103. doi: 10.1016/0896-6273(88)90193-6. [DOI] [PubMed] [Google Scholar]
- Rauschecker J. P., Hahn S. Ketamine-xylazine anaesthesia blocks consolidation of ocular dominance changes in kitten visual cortex. Nature. 1987 Mar 12;326(6109):183–185. doi: 10.1038/326183a0. [DOI] [PubMed] [Google Scholar]
- Rock D. M., Macdonald R. L. The polyamine spermine has multiple actions on N-methyl-D-aspartate receptor single-channel currents in cultured cortical neurons. Mol Pharmacol. 1992 Jan;41(1):83–88. [PubMed] [Google Scholar]
- Sprosen T. S., Woodruff G. N. Polyamines potentiate NMDA induced whole-cell currents in cultured striatal neurons. Eur J Pharmacol. 1990 Apr 25;179(3):477–478. doi: 10.1016/0014-2999(90)90193-a. [DOI] [PubMed] [Google Scholar]
- Sugihara H., Moriyoshi K., Ishii T., Masu M., Nakanishi S. Structures and properties of seven isoforms of the NMDA receptor generated by alternative splicing. Biochem Biophys Res Commun. 1992 Jun 30;185(3):826–832. doi: 10.1016/0006-291x(92)91701-q. [DOI] [PubMed] [Google Scholar]
- Yamazaki M., Mori H., Araki K., Mori K. J., Mishina M. Cloning, expression and modulation of a mouse NMDA receptor subunit. FEBS Lett. 1992 Mar 23;300(1):39–45. doi: 10.1016/0014-5793(92)80160-i. [DOI] [PubMed] [Google Scholar]