Phospholipids modify substrate binding and enzyme activity of human cytochrome P450 27A1

Murtazina, Dilyara A.; Andersson, Ulla; Hahn, In Su; Björkhem, Ingemar; Ansari, Ghulam; Pikuleva, Irina A.

doi:10.1194/jlr.m400300-jlr200

Cited by 23 publications

(22 citation statements)

References 45 publications

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“…Selective phospholipids are thought to be required for proper folding and function of membrane proteins (63). Soluble enzymes, such as CYP27A1, also bind phospholipids and are thought to have their activities regulated by such binding (52). At this point, although the phospholipid-bound crystal structures are intriguing, the most that can be said is that phospholipid cannot be ruled out as a possible ligand class.…”

Section: Discussionmentioning

confidence: 94%

See 1 more Smart Citation

The crystal structures of human steroidogenic factor-1 and liver receptor homologue-1

Wang¹,

Zhang²,

Marimuthu³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

132

134

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Steroidogenic factor-1 (SF-1) and liver receptor homologue-1 (LRH-1) belong to the fushi tarazu factor 1 subfamily of nuclear receptors. SF-1 is an essential factor for sex determination during development and regulates adrenal and gonadal steroidogenesis in the adult, whereas LRH-1 is a critical factor for development of endodermal tissues and regulates cholesterol and bile acid homeostasis. Regulatory ligands are unknown for SF-1 and LRH-1. A reported mouse LRH-1 structure revealed an empty pocket in a region commonly occupied by ligands in the structures of other nuclear receptors, and pocket-filling mutations did not alter the constitutive activity observed. Here we report the crystal structures of the putative ligand-binding domains of human SF-1 at 2.1-Å resolution and human LRH-1 at 2.5-Å resolution. Both structures bind a coactivator-derived peptide at the canonical activationfunction surface, thus adopting the transcriptionally activating conformation. In human LRH-1, coactivator peptide binding also occurs to a second site. We discovered in both structures a phospholipid molecule bound in a pocket of the putative ligand-binding domain. MS analysis of the protein samples used for crystallization indicated that the two proteins associate with a range of phospholipids. Mutations of the pocket-lining residues reduced the transcriptional activities of SF-1 and LRH-1 in mammalian cell transfection assays without affecting their expression levels. These results suggest that human SF-1 and LRH-1 may be ligand-binding receptors, although it remains to be seen if phospholipids or possibly other molecules regulate SF-1 or LRH-1 under physiological conditions.x-ray crystallography ͉ phospholipid ͉ nuclear receptor ͉ steroid ͉ bile S teroidogenic factor-1 (SF-1; AD4BP͞NR5A1) and liver receptor homologue-1 (LRH-1; CPF͞FTF͞NR5A2), expressed in man, are homologues of the fushi tarazu factor-1 of Drosophila (1) and FF1B of fish (2). Together, these factors constitute the NR5A subfamily of nuclear receptors (NRs) (3). SF-1 and LRH-1 function as monomers (4) to regulate genes by binding to similar response elements.SF-1 is expressed in the adrenal, testes, ovary, pituitary, hypothalamus, spleen, and skin and regulates genes that direct biosynthesis of adrenal and gonadal steroids as well as Mullerian hormone and gonadotropins (5, 6). SF-1 is essential for normal adrenal and gonadal development given that SF-1 knockout in mice causes adrenal and gonadal agenesis and impaired gonadotropin expression, resulting in postnatal death due to severe adrenal insufficiency (7,8). SF-1 knockout also causes abnormalities of the ventromedial hypothalamic nucleus, the control center for satiety and feeding, which suggests that SF-1 may have broader roles in the control of metabolism and obesity (9). In humans, partial loss-of-function mutations in SF-1 result in XY sex reversal and adrenal failure (10, 11). Although SF-1 is expressed in the ovary (12), a mutation of SF-1 was observed not to affect ovarian development; thus, SF-1 may no...

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Section: Discussionmentioning

confidence: 94%

“…Sample extraction was performed as described in ref. 52, ending in 200 l of organic fraction, of which 20-l samples were analyzed by using electrospray ionization MS in positive and negative modes (Micromass ZMD MS with MASS-LYNX software, Waters).…”

Section: Methodsmentioning

confidence: 99%

The crystal structures of human steroidogenic factor-1 and liver receptor homologue-1

Wang¹,

Zhang²,

Marimuthu³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

132

134

View full text Add to dashboard Cite

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“…All other chemicals were from Sigma-Aldrich (St. Louis, MO), unless otherwise specified. Recombinant CYP27A1, adrenodoxin reductase, and adrenodoxin were expressed and purified, as described (Murtazina et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

Marketed Drugs Can Inhibit Cytochrome P450 27A1, a Potential New Target for Breast Cancer Adjuvant Therapy

2015

Self Cite

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Cytochrome P450 CYP27A1 is the only enzyme in humans converting cholesterol to 27-hydroxycholesterol, an oxysterol of multiple functions, including tissue-specific modulation of estrogen and liver X receptors. Both receptors seem to mediate adverse effects of 27-hydroxycholesterol in breast cancer when the levels of this oxysterol are elevated. The present work assessed druggability of CYP27A1 as a potential antibreast cancer target. We selected 26 anticancer and noncancer medications, most approved by the Food and Drug Administration, and evaluated them first in vitro for inhibition of purified recombinant CYP27A1 and binding to the enzyme active site. Six strong CYP27A1 inhibitors/binders were identified. These were the two antibreast cancer pharmaceuticals anastrozole and fadrozole, antiprostate cancer drug bicalutamide, sedative dexmedetomidine, and two antifungals ravuconazole and posaconazole. Anastrozole was then tested in vivo on mice, which received subcutaneous drug injections for 1 week. Mouse plasma and hepatic 27-hydroxycholesterol levels were decreased 2.6-and 1.6-fold, respectively, whereas plasma and hepatic cholesterol content remained unchanged. Thus, pharmacologic CYP27A1 inhibition is possible in the whole body and individual organs, but does not negatively affect cholesterol elimination. Our results enhance the potential of CYP27A1 as an antibreast cancer target, could be of importance for the interpretation of Femara versus Anastrozole Clinical Evaluation Trial, and bring attention to posaconazole as a potential complementary anti-breast cancer medication. More medications on the US market may have unanticipated off-target inhibition of CYP27A1, and we propose strategies for their identification.

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“…The hydrophobic N-terminal transmembrane sequence also [93] a All the catalytic activities of P450s were increased by specific anionic phospholipids, with the exception of P450 27A1 interacting with PS: PS inhibited the 5 -cholestane-3 ,7 ,12 -triol hydroxylase activity. The specific substrates of the P450 enzymes are shown in parentheses.…”

Section: Membrane Topology Of P450smentioning

confidence: 98%

Functional Regulation of Hepatic Cytochrome P450 Enzymes by Physicochemical Properties of Phospholipids in Biological Membranes

Ahn

Kim²,

Yun³

et al. 2007

CPPS

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Knowledge regarding the regulation of hepatic cytochrome P450 (P450) is crucial to the fields of drug therapy and drug development, as well as to our understanding of the mechanisms underlying the metabolic activation of toxic and carcinogenic compounds. P450 is a membrane-anchored protein that shows a variety of interaction with membrane phospholipids, which affect the membrane topology and catalytic activities of the protein. In particular, anionic phospholipids, nonbilayer forming lipids, and the degree of saturation of the lipid fatty acyl chain play important roles in the functional regulation of P450, as well as in the bilayer structure of the membrane. However, despite the importance of phospholipids in the regulation of P450s, the interaction of the protein with membrane phospholipids, and the membrane properties induced by phospholipids which regulate P450, are unclear. In this review, we describe the effect of the physicochemical properties of the phospholipid constituents of biological membranes on hepatic P450 catalytic activity, membrane insertion (and/or penetration), and structural changes.

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Phospholipids modify substrate binding and enzyme activity of human cytochrome P450 27A1

Cited by 23 publications

References 45 publications

The crystal structures of human steroidogenic factor-1 and liver receptor homologue-1

The crystal structures of human steroidogenic factor-1 and liver receptor homologue-1

Marketed Drugs Can Inhibit Cytochrome P450 27A1, a Potential New Target for Breast Cancer Adjuvant Therapy

Functional Regulation of Hepatic Cytochrome P450 Enzymes by Physicochemical Properties of Phospholipids in Biological Membranes

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