Galactocerebroside mediates Ca2+ signaling in cultured glioma cells.
Expression of galactocerebroside (GalC) was detected in human glioma cell line (U-87 MG). Exposure of cells to antibody against GalC and fluoresceinated second antibody showed intense fluorescence on the plasma membrane. Possible involvement of GalC in receptor-mediated transmembrane signaling was explored in this cell line. Antibodies raised against GalC were used as ligands. Binding of anti-GalC to these cells caused a transient increase in intracellular free calcium ([Ca2+]i). The response was observed both in the presence and absence of extracellular calcium demonstrating that the rise in [Ca2+]i induced by anti-GalC was due to an influx of Ca2+ through plasma membrane as well as the release of Ca2+ from intracellular pools. Ca2+ influx was blocked by verapamil, indicating that influx is mediated by voltage-sensitive channels. Our results suggest that GalC can play a role in transmembrane signaling by modulation of voltage-sensitive Ca2+ channels.
Joshi
P G
PG
Department of Biophysics, National Institute of Mental Health and Neuro Sciences, Bangalore, India.
Mishra
S
S
D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology*; D005699:Galactosylceramides / Q000032:analysis / Q000502:physiology*; D005910:Glioma / Q000503:physiopathology*; D006801:Humans; D007150:Immunohistochemistry; D015398:Signal Transduction / Q000502:physiology*; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D005699:Galactosylceramides; C002454:galactocerebroside; D002118:Calcium