ULTRAVIOLET-RADIATION INDUCES PHOSPHORYLATION OF THE EPIDERMAL GROWTH-FACTOR RECEPTOR

Ultraviolet light in solar radiation is responsible for more than 600, 000 malignancies each year in the United States alone, making it the m ost efficient environmental carcinogen known. Ultraviolet radiation-in duced direct DNA damage is thought to be responsible for its initiatin g properties, while the promotional aspects of such radiation are poor ly defined and only recently gaining attention. We show here for the f irst time that physiologically relevant doses of ultraviolet radiation induce phosphorylation of the epidermal growth factor receptor in A43 1 keratinocytes at tyrosine sites within 30 min. Such alteration of th is major signal transduction system is probably an important step in t he ultraviolet radiation-induced, epidermal cell-signalling cascade.