PDF(Pubmed)
Abstract：
Cytochrome P450 3A4 and 2D6 (EC 1.14.13.97 and 1.14.14.1; CYP3A4 and 2D6) are heme-containing enzymes that catalyze the oxidation of a wide number of xenobiotic and drug substrates and thus broadly impact human biology and pharmacologic therapies. Although their activities are directly proportional to their heme contents, little is known about the cellular heme delivery and insertion processes that enable their maturation to functional form. We investigated the potential involvement of GAPDH and chaperone Hsp90, based on our previous studies linking these proteins to intracellular heme allocation. We studied heme delivery and insertion into CYP3A4 and 2D6 after they were transiently expressed in HEK293T and GlyA CHO cells or when naturally expressed in HEPG2 cells in response to rifampicin, and also investigated their associations with GAPDH and Hsp90 in cells. The results indicate that GAPDH and its heme binding function is involved in delivery of mitochondria-generated heme to apo-CYP3A4 and 2D6, and that cell chaperone Hsp90 is additionally involved in driving their heme insertions. Uncovering how cells allocate heme to CYP3A4 and 2D6 provides new insight on their maturation processes and how this may help to regulate their functions in health and disease.
摘要：
细胞色素P4503A4和2D6(EC1.14.13.97和1.14.14;CYP3A4和2D6)是含血红素的酶,其催化大量异生物质和药物底物的氧化,因此广泛影响人类生物学和药物疗法。尽管它们的活动与血红素含量成正比，人们对使血红素成熟到功能形式的细胞血红素递送和插入过程知之甚少。基于我们先前的将这些蛋白质与细胞内血红素分配联系起来的研究，我们调查了GAPDH和伴侣Hsp90的潜在参与。我们研究了血红素在HEK293T和GlyACHO细胞中瞬时表达或在HEPG2细胞中自然表达以响应利福平后，血红素的递送和插入CYP3A4和2D6中。并研究了它们与细胞中GAPDH和Hsp90的关联。结果表明，GAPDH及其血红素结合功能参与线粒体生成的血红素向apo-CYP3A4和2D6的递送，并且细胞伴侣Hsp90还参与驱动其血红素插入。揭示细胞如何将血红素分配给CYP3A4和2D6，为它们的成熟过程以及这如何有助于调节它们在健康和疾病中的功能提供了新的见解。
