Hashida T, Yasumoto S
Laboratory of Molecular and Cell Biology, Kanagawa Cancer Center Research Institute, Yokohama, Japan.
Biochem Biophys Res Commun. 1990 Oct 30;172(2):958-64. doi: 10.1016/0006-291x(90)90769-j.
The present study describes hyper-phosphorylation of E7-oncoprotein of human papillomavirus (HPV) type 16 in epidermal keratinocytes. We found that highly phosphorylated E7-oncoprotein was present in epidermal keratinocytes but little in fibroblasts. The E7 oncoprotein contains serine residues (Ser-Ser-Glu-Glu-Glu) capable of being phosphorylated by casein kinase II (CK II). Extracts from various cell lines including human origins transformed by HPV 16 were examined for the casein kinase activity. The results showed that CK II activity was present at significantly high levels in keratinocytes but little or no detectable levels of the activity in human fibroblasts. These differential CK II activities in host cells may play a part in the differential transforming activity by E7-oncoprotein.
本研究描述了人乳头瘤病毒16型（HPV）的E7癌蛋白在表皮角质形成细胞中的过度磷酸化。我们发现，高度磷酸化的E7癌蛋白存在于表皮角质形成细胞中，但在成纤维细胞中含量很少。E7癌蛋白含有能够被酪蛋白激酶II（CK II）磷酸化的丝氨酸残基（Ser-Ser-Glu-Glu-Glu）。检测了包括被HPV 16转化的人源细胞系在内的各种细胞系提取物的酪蛋白激酶活性。结果显示，CK II活性在角质形成细胞中显著高水平存在，但在人成纤维细胞中活性水平很低或无法检测到。宿主细胞中这些不同的CK II活性可能在E7癌蛋白的不同转化活性中起作用。
