Moonlighting function of glycerol kinase causes systems-level changes in rat hepatoma cells

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• 作者：Ganesh Sriram ; Lilly S. Parr ; Lola Rahib ; James C. Liao ; Katrina M. Dipple
• 关键词：Glycerol kinase ; Moonlighting protein ; Glucocorticoid receptor ; Microarray analysis ; Network component analysis ; Transcriptional regulation
• 刊名：Metabolic Engineering
• 出版年：2010
• 出版时间：July 2010
• 年：2010
• 卷：12
• 期：4
• 页码：332-340
• 全文大小：979 K

文摘

Glycerol kinase (GK) is an enzyme with diverse (moonlighting) cellular functions. GK overexpression affects central metabolic fluxes substantially; therefore, to elucidate the mechanism underlying these changes, we employed a systems-level evaluation of GK overexpression in H4IIE rat hepatoma cells. Microarray analysis revealed altered expression of genes in metabolism (central carbon and lipid), which correlated with previous flux analysis, and of genes regulated by the glucocorticoid receptor (GR). Oil Red O staining showed that GK overexpression leads to increased fat storage in H4IIE cells. Network component analysis revealed that activities of peroxisome proliferator-activated receptor α, GR, and seven other transcription factors were altered by GK overexpression. The increased activity of GR was experimentally verified by quantitative RT-PCR of GR-responsive genes in the presence and absence of the glucocorticoid agonist, dexamethasone. This systems biology approach further emphasizes GK's essential role in central and lipid metabolism and experimentally verifies GK's alternative (moonlighting) function of affecting GR transcription factor activity.