Tyrosine protein kinase activity of the EGF receptor is required to induce activation of receptor-operated calcium channels |
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Authors: | Y Chapron C Cochet S Crouzy T Jullien M Keramidas J Verdetti |
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Affiliation: | Laboratoire de Biophysique Moléculaire et Cellulaire (UA 520 du CNRS), Grenoble, France. |
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Abstract: | 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. |
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