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Bradykinin‐stimulated transient modulation of epidermal growth factor receptors in A‐431 human epidermoid carcinoma cells
Author(s) -
Hosoi Kazuo,
Kurihara Kinji,
Ueha Takao
Publication year - 1993
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041570102
Subject(s) - bradykinin , epidermal growth factor , phosphorylation , protein kinase c , receptor , protein kinase a , endocrinology , medicine , inositol trisphosphate , 12 o tetradecanoylphorbol 13 acetate , chemistry , biology , biochemistry , inositol , phorbol ester
Of nine biological factors (ATP, bradykinin, vasopressin, substance P, angiotensin II, norepinephrine, epinephrine, 12‐tetradecanoylphorbol 13‐acetate (TPA), and A23187 calcium ionophore) examined, bradykinin, as well as ATP, TPA, and A23187, significantly increased the phosphorylation of epidermal growth factor (EGF) receptors and reduced the binding of EGF to their high‐affinity site. The reduction in EGF binding by bradykinin, ATP, and TPA was similarly reversed by concomitant incubation with staurosporine, a protein kinase C inhibitor, implying that the phosphorylation of EGF receptors was catalyzed probably by a protein kinase C of the same or similar type in each case. This possibility was confirmed by the fact that the major phosphorylation site of EGF receptors by the stimulation with either bradykinin, ATP or TPA was the same (Thi‐654). Different from the stimulations with ATP and TPA, the effect of bradykinin of decreasing the high‐affinity EGF binding was transient (a minimum binding at 2.5 min); the reduced EGF binding was, however, sustained for up to 30 min in the presence of calyculin A, a phosphoprotein phosphatase inhibitor. Moreover, the homogenate prepared from bradykinin‐stimulated A‐431 cells had stronger dephosphorylation activity for phosphorylated EGF receptors than that from control cells. These results suggest that bradykinin stimulates both the protein kinase C system and a phosphoprotein phosphatase(s) activity in A‐431 cells. Such biphasic effects of bradykinin to phosphorylate and dephosphorylate EGF receptors via protein kinase C and a phosphoprotein phosphatase, respectively, imply a homeostatic control of receptor function in regulating phosphorylation level by the same bioactive factor. © 1993 Wiley‐Liss, Inc.