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Identification of a second region of the beta-subunit involved in regulation of calcium channel inactivation.
- Source :
-
The American journal of physiology [Am J Physiol] 1996 Nov; Vol. 271 (5 Pt 1), pp. C1539-45. - Publication Year :
- 1996
-
Abstract
- Previous studies have shown that NH2 termini of the type 1 and 2 beta-subunits modulate the rate at which the neuronal alpha 1E calcium channel inactivates in response to voltage and that they do so independently of their common effect to stimulate activation by voltage (R. Olcese, N. Qin, T. Schneider, A. Neely, X. Wei, E. Stefani, and L. Birnbaumer, Neuron 13: 1433-1438, 1994). By constructing NH2-terminal deletions of several splice variants of beta-subunits, we have now found differences in the way they affect the rate of alpha 1E inactivation that lead us to identify a second domain that also regulates the rate of voltage-induced inactivation of the Ca2+ channel. This second domain, named segment 3, lies between two regions of high-sequence identity between all known beta-subunits and exists in two lengths (long and short), each encoded in a separate exon. Beta-Subunits with the longer 45- to 53-amino acid version cause the channel to inactivate more slowly than subunits with the shorter 7-amino acid version. As is the case for the NH2 terminus, the segment 3 does not affect the regulation of channel activation by the beta-subunit. In addition, the effect of the NH2-terminal segment prevails over that of the internal segment. This raises the possibility that phosphorylation, other types of posttranslational modification, or interaction with other auxiliary calcium channel subunits may be necessary to unmask the regulatory effect of the internal segment.
- Subjects :
- Alternative Splicing
Amino Acid Sequence
Animals
Calcium Channels biosynthesis
Cell Membrane physiology
Exons
Female
Genetic Variation
Humans
Macromolecular Substances
Membrane Potentials
Patch-Clamp Techniques
Polymerase Chain Reaction
RNA, Complementary
Recombinant Fusion Proteins biosynthesis
Recombinant Fusion Proteins chemistry
Sequence Deletion
Transcription, Genetic
Xenopus
Calcium Channels chemistry
Calcium Channels physiology
Oocytes physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9513
- Volume :
- 271
- Issue :
- 5 Pt 1
- Database :
- MEDLINE
- Journal :
- The American journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 8944637
- Full Text :
- https://doi.org/10.1152/ajpcell.1996.271.5.C1539