Alterations in Exocytosis Induced by Neuronal Ca2+ Sensor-1 in Bovine Chromaffin Cells
Journal
Journal of Neuroscience
Journal Volume
22
Journal Issue
7
Pages
2427-2433
Date Issued
2002
Author(s)
Abstract
A variety of Ca2+ binding proteins are known to play an integral role in catecholamine release from synapses as well as secretory cells, such as chromaffin cells. The Drosophila protein frequenin and its mammalian homolog neuronal Ca2+ sensor-1 (NCS-1) belong to a family of Ca 2+ sensors with EF hands that bind Ca2+ and then interact with other proteins. Frequenin/NCS-1 has been shown to enhance exocytotic activity in addition to altering Ca2+ channel regulation. To better understand how NCS-1 regulates stimulus-secretion coupling, bovine chromaffin cells were infected with Semliki Forest virus (SFV) vectors containing the rat NCS-1 gene. Cells were studied in the perforated whole-cell patch-clamp configuration. Membrane capacitance was monitored as an indicator of exocytosis-endocytosis. Exocytosis elicited by membrane depolarization was not significantly different between cells infected with SFV expressing green fluorescent protein (GFP) or GFP plus NCS-1, except that the overexpression of NCS-1 resulted in a faster rundown in exocytosis. When cells were stimulated with histamine, NCS-1 overexpression led to higher exocytosis, as well as [Ca2+]i elevation. Immunocytochemistry showed a similar distribution of NCS-1 and phosphatidylinositol 4-kinase β (PI4Kβ). NCS-1 and PI4Kβ coimmunoprecipitate, opening up the possibility that the two proteins directly interact. These results suggest that NCS-1 may regulate cellular activity through the modulation of the phosphatidylinositol signaling pathway.
Subjects
Calcium; Chromaffin; Exocytosis; Histamine; IP3; NCS-1; Neuronal calcium sensor; Phosphatidylinositol; Semliki Forest virus vector
SDGs
Other Subjects
green fluorescent protein; histamine; M protein; neuronal calcium sensor 1; phosphatidylinositol kinase; unclassified drug; virus vector; 1-phosphatidylinositol-4-phosphate 5-kinase; calcium; calcium binding protein; frequenin calcium sensor proteins; neuronal calcium sensor; neuropeptide; phosphatidylinositol 4 phosphate kinase; phosphotransferase; sodium; animal cell; article; cattle; cell stimulation; chromaffin cell; controlled study; endocytosis; exocytosis; immunocytochemistry; membrane depolarization; nonhuman; patch clamp; priority journal; protein expression; Semliki Forest alphavirus; stimulus secretion coupling; virus infection; action potential; animal; cell culture; cell membrane; cell membrane potential; chromaffin cell; cytology; drug effect; electric capacitance; electrostimulation; gene vector; genetic transfection; genetics; metabolism; physiology; protein binding; rat; Action Potentials; Animals; Calcium; Calcium-Binding Proteins; Cattle; Cell Membrane; Cells, Cultured; Chromaffin Cells; Electric Capacitance; Electric Stimulation; Endocytosis; Exocytosis; Genetic Vectors; Histamine; Membrane Potentials; Neuronal Calcium-Sensor Proteins; Neuropeptides; Patch-Clamp Techniques; Phosphotransferases (Alcohol Group Acceptor); Protein Binding; Rats; Semliki forest virus; Sodium; Transfection
Type
journal article