RT Journal Article
SR Electronic
T1 Isoform-Specific Regulation of the Na+/Ca2+ Exchanger in Rat Astrocytes and Neurons by PKA
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4833
OP 4841
DO 10.1523/JNEUROSCI.18-13-04833.1998
VO 18
IS 13
A1 Suiwen He
A1 Abdul Ruknudin
A1 Linda L. Bambrick
A1 W. Jon Lederer
A1 Dan H. Schulze
YR 1998
UL http://www.jneurosci.org/content/18/13/4833.abstract
AB The Na+/Ca2+ exchanger is a major transporter of Ca2+ in neurons and glial cells. The Na+/Ca2+ exchanger gene NCX1 expresses tissue-specific isoforms of the Na+/Ca2+ exchanger, and the isoforms have been examined here quantitatively using primary cultures of astrocytes and neurons. We present a PCR-based quantitative method, quantitative end-labeled reverse transcription-PCR (QERT-PCR), to determine the relative amounts of the NCX1 isoforms present in these cells. Six exons (A, B, C, D, E, and F) are alternatively spliced to produce the known NCX1 isoforms. Three exon B-containing isoforms (BDEF, BDF, and BD) are the predominant transcripts in primary rat cortical astrocytes and in C6 glioma cells. In contrast, exon A-containing isoforms (ADF and AD) are the predominant transcripts in primary rat hippocampal neurons. Functional differences between full-length constructs of NCX1 containing either the astrocyte isoform BD or the neuron isoform AD were examined in a Xenopusoocyte expression system. Although both isoforms function normally, the activity of the AD isoform can be increased 39% by activation of protein kinase A (PKA), whereas that of the BD isoform is not affected. We conclude that specific NCX1 isoforms are expressed in distinct patterns in astrocytes and neurons. Furthermore, the activity of a neuronal (but not glial) isoform of the Na+/Ca2+ exchanger can be altered by the activation of the PKA pathway.