期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1976
卷号:73
期号:8
页码:2711-2715
DOI:10.1073/pnas.73.8.2711
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:The concentration of a calcium-binding protein modulator of 3':5'-cyclic-nucleotide phosphodiesterase (EC 3.1.4.17 ; 3':5'-cyclic-nucleotide 5'-nucleotidohydrolase) activity is increased in chicken embryo fibroblasts upon transformation by Rous sarcoma virus. This modulator protein from fibroblasts, which has roughly the same molecular size, charge, and functional properties as that isolated from chicken brain, comprises approximately 1.32% of the soluble protein in homogenates of fibroblasts infected and transformed by Rous sarcoma virus. In comparison, the modulator comprises approximately 0.30% of the soluble protein in homogenates of normal fibroblasts from confluent cultures and 0.36% of the soluble protein in homogenates of fibroblasts infected with a transformation-defective mutant of Rous sarcoma virus. Modulator levels in normal fibroblasts at subconfluent cell densities are 0.42-0.76% of the homogenate soluble protein, i.e., between that found in confluent normal fibroblasts and in fibroblasts transformed by Rous sarcoma virus. These observations suggest that the levels of the modulator protein are elevated under conditions in which chicken embryo fibroblasts are undergoing rapid growth and have decreased adenosine 3':5'-cyclic monophosphate levels.