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Cell-specific posttranslational events affect functional expression at the plasma membrane but not tetrodotoxin sensitivity of the rat brain IIA sodium channel α-subunit expressed in mammalian cells

Yang, Xian-cheng and Labarca, Cesar and Nargeot, Joel and Ho, Begonia Y. and Elroy-Stein, Orna and Moss, Bernard and Davidson, Norman and Lester, Henry A. (1992) Cell-specific posttranslational events affect functional expression at the plasma membrane but not tetrodotoxin sensitivity of the rat brain IIA sodium channel α-subunit expressed in mammalian cells. Journal of Neuroscience, 12 (1). pp. 268-277. ISSN 0270-6474. PMCID PMC6575683. doi:10.1523/jneurosci.12-01-00268.1992. https://resolver.caltech.edu/CaltechAUTHORS:20191101-161058438

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Abstract

The rat brain IIA Na⁺ channel alpha-subunit was expressed and studied in mammalian cells. Cells were infected with a recombinant vaccinia virus (VV) carrying the bacteriophage T7 RNA polymerase gene and were transfected with cDNA encoding the IIA Na⁺ channel α-subunit under control of a T7 promoter. Whole-cell patch-clamp recording showed that functional IIA channels were expressed efficiently (~10 channels/ µm² in approximately 60% of cells) in Chinese hamster ovary (CHO) cells and in neonatal rat ventricular myocytes but were expressed poorly in undifferentiated BC₃H1 cells and failed to express in Ltk⁻ cells. However, voltage-dependent Drosophila Shaker H4 K⁺ channels and Escherichia coli β-galactosidase were expressed efficiently in all four cell types with VV vectors. Because RNA synthesis probably occurs without major differences in the cytoplasm of all infected cell types under the control of the T7 promoter and T7 polymerase, we conclude that cell type-specific expression of the Na⁺ channel probably reflects differences at posttranslational steps. The gating properties of the IIA Na⁺ currents expressed in cardiac myocytes differed from those expressed in CHO cells; most noticeably, the IIA Na⁺ currents displayed more rapid macroscopic inactivation when expressed in cardiac myocytes. These differences also suggest cell- specific posttranslational modifications. IIA channels were blocked by ~90% by 90 nM TTX when expressed either in CHO cells or in cardiac myocytes; the latter also continued to display endogenous TTX- resistant Na⁺ currents. Therefore, the TTX binding site of the channel is not affected by cell-specific modifications and is encoded by the primary amino acid sequence.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1523/jneurosci.12-01-00268.1992DOIArticle
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6575683PubMed CentralArticle
ORCID:
AuthorORCID
Lester, Henry A.0000-0002-5470-5255
Alternate Title:Cell-specific posttranslational events affect functional expression at the plasma membrane but not tetrodotoxin sensitivity of the rat brain IIA sodium channel alpha-subunit expressed in mammalian cells
Additional Information:© 1992 Society for Neuroscience. Received May 6, 1991; revised Aug. 15, 1991; accepted Aug. 26, 1991. We thank Carolyn Nolan and Euk Kwon for excellent technical assistance. This work is supported by grants from the NIH (NS-11756 and GM-29836), the Muscular Dystrophy Association, the Multiple Sclerosis Society, and NATO (CRG 890374) and by postdoctoral fellowships from the Muscular Dystrophy Association (X.-C.Y.) and the American Heart Association, Greater Los Angeles Chapter (B.Y.H.).
Funders:
Funding AgencyGrant Number
NIHNS-11756
NIHGM-29836
Muscular Dystrophy AssociationUNSPECIFIED
Multiple Sclerosis SocietyUNSPECIFIED
North Atlantic Treaty Organization (NATO)CRG 890374
American Heart Association, Greater Los Angeles AffiliateUNSPECIFIED
Issue or Number:1
PubMed Central ID:PMC6575683
DOI:10.1523/jneurosci.12-01-00268.1992
Record Number:CaltechAUTHORS:20191101-161058438
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20191101-161058438
Official Citation:Cell-specific posttranslational events affect functional expression at the plasma membrane but not tetrodotoxin sensitivity of the rat brain IIA sodium channel alpha-subunit expressed in mammalian cells. XC Yang, C Labarca, J Nargeot, BY Ho, O Elroy-Stein, B Moss, N Davidson, HA Lester. Journal of Neuroscience 1 January 1992, 12 (1) 268-277; DOI: 10.1523/JNEUROSCI.12-01-00268.1992
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99633
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:01 Nov 2019 23:26
Last Modified:16 Nov 2021 17:48

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