Stable transfection of calbindin-D28k into the GH3 cell line alters calcium currents and intracellular calcium homeostasis.
Previous work demonstrating the presence and differential distribution of Ca(2+)-binding proteins in the CNS has led to the proposal that cytosolic proteins, such as calbindin-D28k (CB), may play a pivotal role in neurons. We have used a retrovirus containing the full-length cDNA for CB to transfect the pituitary tumor cell line GH3, to generate CB-expressing GH3 cells and to investigate whether ionic channel activities as well as the concentration of intracellular free Ca2+ ([Ca2+]i) homeostasis could be altered by the presence of this Ca(2+)-binding protein. We show that CB-transfected GH3 cells exhibited lower Ca2+ entry through voltage-dependent Ca2+ channels and were better able to reduce [Ca2+]i transients evoked by voltage depolarizations than the wild-type parent cell line. These observations provide a mechanism by which CB may protect tissues against Ca(2+)-mediated excitotoxicity.
Lledo
P M
PM
Department of Neurobiology, Institute of Animal Physiology and Genetic Research, Babraham, Cambridge, United Kingdom.
Somasundaram
B
B
Morton
A J
AJ
Emson
P C
PC
Mason
W T
WT
D000818:Animals; D064092:Calbindin 1; D064026:Calbindins; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002614:Chelating Agents / Q000494:pharmacology; D004553:Electric Conductivity; D015870:Gene Expression; D005822:Genetic Vectors; D006706:Homeostasis / Q000502:physiology*; D010911:Pituitary Neoplasms; D051381:Rats; D012190:Retroviridae / Q000235:genetics; D064030:S100 Calcium Binding Protein G / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured
C576500:Calb1 protein, rat; D064092:Calbindin 1; D064026:Calbindins; D015220:Calcium Channels; D002614:Chelating Agents; D064030:S100 Calcium Binding Protein G; D002118:Calcium