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Neuronal Ca2+ sensor-1/frequenin functions in an autocrine pathway regulating Ca2+ channels in bovine adrenal chromaffin cells.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2000 Dec 22; Vol. 275 (51), pp. 40082-7. - Publication Year :
- 2000
-
Abstract
- NCS-1/frequenin belongs to a family of EF-hand-containing Ca(2+) sensors expressed mainly in neurons. Overexpression of NCS-1/frequenin has been shown to stimulate neurotransmitter release but little else is known of its cellular roles. We have constructed an EF-hand mutant, NCS-1(E120Q), as a likely dominant inhibitor of cellular NCS-1 function. Recombinant NCS-1(E120Q) showed an impaired Ca(2+)-dependent conformational change but could still bind to cellular proteins. Transient expression of this mutant, but not NCS-1, in bovine adrenal chromaffin cells increased non-L-type Ca(2+) channel currents. Cells expressing NCS-1(E120Q) no longer responded effectively to the removal of autocrine purinergic/opioid inhibition of Ca(2+) currents but still showed voltage-dependent facilitation. These data are consistent with the existence of both voltage-dependent and voltage-independent pathways for Ca(2+) channel inhibition in chromaffin cells. Our results suggest a novel function for NCS-1 specific for the voltage-independent autocrine pathway that negatively regulates non-L-type Ca(2+) channels in chromaffin cells.
- Subjects :
- Animals
Base Sequence
Calcium-Binding Proteins metabolism
Cattle
Cells, Cultured
DNA Primers
Ion Channel Gating
Nerve Tissue Proteins metabolism
Neuronal Calcium-Sensor Proteins
Calcium Channels physiology
Calcium-Binding Proteins physiology
Nerve Tissue Proteins physiology
Neuropeptides physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 275
- Issue :
- 51
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 11006299
- Full Text :
- https://doi.org/10.1074/jbc.M008603200