Regulation of capacitative Ca2+ entry by tyrosine phosphorylation in the neural retina of chick embryo.
Capacitative Ca2+ entry occurs in the neural retina of chick embryo during neurogenesis. We studied the effects of blockers of capacitative Ca2+ entry (SK&F 96365, Zn2+, Ni2+), genistein, a tyrosine kinase inhibitor and vanadate, a protein-phosphotyrosine phosphatase inhibitor in the embryonic chick retina with fura-2 fluorescence measurements. After incubation of the retina in a Ca2+-free solution with or without an inhibitor of Ca2+ pumps of intracellular Ca2+ stores, re-introduction of extracellular Ca2+ caused capacitative Ca2+ entry which was inhibited by SK&F 96365 (10 microM), Zn2+ (1 mM), Ni2+ (5 mM) and genistein (100 microM). On the contrary, vanadate (1 mM) enhanced the Ca2+ entry. These results suggested that tyrosine phosphorylation was involved in the activation of capacitative Ca2+ entry.
Zhou
W L
WL
Department of Physiology I, Nara Medical University, Kashihara, Japan.
Sugioka
M
M
Sakaki
Y
Y
Yamashita
M
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002642:Chick Embryo; D004791:Enzyme Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D012160:Retina / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
D004791:Enzyme Inhibitors; D014638:Vanadates; D014443:Tyrosine; D002118:Calcium