PMID: 9166850Jun 1, 1997Paper

Control of cell cycle progression in human natural killer cells through redox regulation of expression and phosphorylation of retinoblastoma gene product protein.

Blood
A Yamauchi, E T Bloom

Abstract

Using thiol deprivation, we have previously shown that the response of natural killer (NK) cells to interleukin-2 (IL-2) is subject to redox regulation downstream of IL-2 binding and internalization. We have now used the IL-2-dependent cell line, NK3.3 to study redox regulation of NK cells further, and found that NK3.3 cells neither incorporated [3H]-thymidine nor completed the G1-S phase transition in medium lacking the thiol-related compounds, L-cystine, and glutathione, despite the presence of sufficient IL-2. Thiol deprivation did not alter the induction of DNA interferon-gamma activated sequence (GAS)-binding activity in response to IL-2. However, the retinoblastoma gene product (RB), a cyclin-dependent kinase (CDK) substrate, was phosphorylated within 24 hours after IL-2 stimulation in standard medium, but its expression and phosphorylation were reduced in thiol-depleted medium in both NK3.3 cells and freshly isolated NK cells. These reductions were not associated with an increased level of p27Kip1, an inhibitor of CDKs CDK6/2 in association with G1 cyclins. Reducing agents, N-acetylcysteine, reduced glutathione or 2-ME restored both RB phosphorylation and DNA synthesis in thiol-deprived NK3.3 cells. The in vitro kinase a...Continue Reading

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