SEARCH:   Advanced

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Ogawa, K Articles by Okuma, M Search for Related Content PubMed PubMed Citation Articles by Ogawa, K Articles by Okuma, M Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  High expression of c-kit in K562YO cells due to the prolonged half-life of its mRNA: the effects of modification with serine/threonine kinase signals K Ogawa, Y Takeda, M Tashima, H Sawai, T Toi, T Okazaki, H Sawada, Y Maruyama and M Okuma Department of Internal Medicine, Faculty of Medicine, Kyoto University, Japan. We previously reported that the K562 cell line K562YO expressed a high level of the c-kit gene. In this study, we analyzed the mechanism of this expression and investigated the effects of the serine/threonine kinases such as protein kinase C (PKC) and cyclic adenosine 3',5'- monophosphate (cAMP)-dependent kinase (PKA) on it. The half-life of the c-kit mRNA in K562YO cells was greater than 10 hours, compared with 2 hours in the original K562 cells, which expressed a very low level of c- kit mRNA. This prolonged half-life can contribute to the high level of c-kit expression in K562YO cells. Cycloheximide (CHX), a protein synthesis inhibitor, caused increases in c-kit mRNA levels in K562YO cells. 12-O-tetradecanoylphorbol-13-acetate (TPA), by which PKC was activated at first and downregulated in a late phase, gradually decreased c-kit mRNA in K562YO cells until 9 hours and then returned to the control level 24 hours after treatment. TPA also rapidly decreased c-kit protein level on the membranes. In whole cells, c-kit protein was also decreased 6 hours after incubation with TPA. Calphostin C, a light- dependent PKC inhibitor, decreased c-kit mRNA levels within 30 minutes in a light-dependent manner. It also decreased c-kit protein in whole cells 2 hours after the addition. However, it increased the amount of c- kit protein on the cell surfaces. Dibutyryl cyclic AMP (dbc-AMP) increased c-kit mRNA as well as c-kit protein on membranes and in whole cells. Run-on transcriptional assay suggested that the agent (dbc-AMP) enhanced the transcription rate of the gene. These results suggest that c-kit protein on the membranes is downregulated by PKC activation and upregulated by PKC inhibition. In the whole cell lysate, c-kit proteins are decreased by PKC inhibition through downregulation of mRNA. On the other hand, the elevation of an intracellular cAMP level causes upregulation of both the mRNA and c-kit protein on membranes and in whole cells through enhanced transcription. Thus, c-kit gene expression is apparently modulated by PKC and PKA. Volume 85, Issue 6, pp. 1496-1503, 03/15/1995 Copyright © 1995 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: E. B. Sambol, G. Ambrosini, R. C. Geha, P. T. Kennealey, P. DeCarolis, R. O'Connor, Y. V. Wu, M. Motwani, J.-H. Chen, G. K. Schwartz, et al. Flavopiridol Targets c-KIT Transcription and Induces Apoptosis in Gastrointestinal Stromal Tumor Cells Cancer Res., June 1, 2006; 66(11): 5858 - 5866. [Abstract] [Full Text] [PDF]

	Copyright © 1995 by American Society of Hematology         Online ISSN: 1528-0020