Vascular-specific increase in exon 1B-encoded CAV1.2 channels in spontaneously hypertensive rats.
BACKGROUND
The vasculature of the adult spontaneously hypertensive rat (SHR) is known to express more functional L-type Ca channels than the vasculature of normotensive Wistar Kyoto (WKY) rats, but it is not known which Ca(V)1.2 channel isoform is upregulated.


METHODS
Western blots and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) were used to compare the expression levels of Ca(V)1.2 channel protein and message in selected tissues of adult SHR and WKY rats.


RESULTS
The results indicate overexpression in SHR vasculature specifically of the short exon 1b-encoded amino terminus Ca(V)1.2 isoform. Brain and visceral smooth muscle expressing the same isoform were not similarly affected. Differences in message levels are insufficient to account for the differences in isoform-specific protein levels.


CONCLUSIONS
We conclude that SHR vasculature must regulate the channel postranscriptionally. Further experiments will be required to determine whether this involves translation of protein from exon 1b-specific transcripts more efficiently, posttranslational chaperoning to the surface membrane more efficiently, or selective degradation of the short amino terminus form of the protein more slowly than in WKY vasculature.
Wang
Wen-Ze
WZ
Department Neuroscience & Cell Biology, University of Texas Medical Branch, Galveston, Texas, USA.
Saada
Nehad
N
Dai
Bosong
B
Pang
Li
L
Palade
Philip
P
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001011:Aorta / Q000378:metabolism; D001808:Blood Vessels / Q000378:metabolism*; D005091:Exons / Q000235:genetics*; D051663:Kv1.2 Potassium Channel / Q000235:genetics*; D008297:Male; D009928:Organ Specificity; D051381:Rats; D011918:Rats, Inbred SHR
D051663:Kv1.2 Potassium Channel