Tyrosine protein kinase activity of the EGF receptor is required to induce activation of receptor-operated calcium channels.
We have investigated the effects of epidermal growth factor (EGF) on calcium ion channels in A431 epidermoid carcinoma cells. We have found that: -1- EGF stimulates Ca2+ channels. -2- EGF stimulated Ca2+ channels are voltage independent, exhibit a low conductance (8 pS) and a bursting multichannels activity (BMC). -3- Activation of the tyrosine-kinase function of the EGF receptor is required to generate Ca2+ current. -4- Inositol (1,4,5) triphosphate (Ins (1,4,5) P3) and EGF have similar effect on the channel activation. These results suggest that: stimulation of tyrosine-kinase activity of the EGF receptor, production of Ins (1,4,5)P3 and calcium entry via voltage independent channels are important connected steps in mediating the mitogenic effect of this growth factor.
Chapron
Y
Y
Laboratoire de Biophysique Moléculaire et Cellulaire (UA 520 du CNRS), Grenoble, France.
Cochet
C
C
Crouzy
S
S
Jullien
T
T
Keramidas
M
M
Verdetti
J
J
D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D007295:Inositol Phosphates; D004815:Epidermal Growth Factor; D015544:Inositol 1,4,5-Trisphosphate; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D002118:Calcium