title: Localization of putative binding sites for cyclic guanosine monophosphate and the anti-cancer drug 5-fluoro-2'-deoxyuridine-5'-monophosphate on ABCC11 in silico models.
abstract: BACKGROUND
  The Multidrug Resistance Protein ABCC11/MRP8 is expressed in physiological barriers and tumor breast tissues in which it secretes various substrates including cGMP (cyclic guanosine monophosphate) and 5FdUMP (5-fluoro-2'-deoxyuridine-5'-monophosphate), the active metabolite of the anticancer drug 5-FluoroUracil (frequently included to anticancer therapy).Previously, we described that ABCC11 high levels are associated to the estrogen receptor (ER) expression level in breast tumors and in cell lines resistant to tamoxifen. Consequently, by lowering the intracellular concentration of anticancer drugs, ABCC11 likely promotes a multidrug resistance (MDR) phenotype and decreases efficiency of anticancer therapy of 5FdUMP. Since no experimental data about binding sites of ABCC11 substrate are available, we decided to in silico localize putative substrate interaction sites of the nucleotide derivatives. Taking advantage of molecular dynamics simulation, we also analysed their evolution under computational physiological conditions and during the time.
  
  
  RESULTS
  Since ABCC11 crystal structure is not resolved yet, we used the X-ray structures of the mouse mdr3 (homologous to human ABCB1) and of the bacterial homolog Sav1866 to generate two independent ABCC11 homology models in inward- and outward-facing conformations. Based on docking analyses, two putative binding pockets, for cGMP and 5FdUMP, were localized in both inward- and outward-facing conformations. Furthermore, based on our 3D models, and available biochemical data from homologous transporters, we identified several residues, potentially critical in ABCC11 transport function. Additionally, molecular dynamics simulation on our inward-facing model revealed for the first time conformation changes assumed to occur during transport process.
  
  
  CONCLUSIONS
  ABCC11 would present two binding sites for cGMP and for 5FdUMP. Substrates likely first bind at the intracellular side of the transmembrane segment while ABCC11 is open forward the cytoplasm (inward-facing conformation). Then, along with conformational changes, it would pass through ABCC11 and fix the second site (close to the extracellular side), until the protein open itself to the extracellular space and allow substrate release.
authors: INSERM, UMR-S1052, Centre de Recherche en Cancérologie de Lyon, Lyon F-69008, France.
authors: Mylène
authors: M
authors: Honorat
authors: Raphaël
authors: R
authors: Terreux
authors: Pierre
authors: P
authors: Falson
authors: Attilio
authors: A
authors: Di Pietro
authors: Charles
authors: C
authors: Dumontet
authors: Lea
authors: L
authors: Payen
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000737:chemistry / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D006152:Cyclic GMP / Q000737:chemistry / Q000378:metabolism*; D030562:Databases, Protein; D005468:Fluorodeoxyuridylate / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D051379:Mice; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D055672:Static Electricity
chemical_list: C435500:ABCC11 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D005468:Fluorodeoxyuridylate; C095122:multidrug resistance protein 3; D006152:Cyclic GMP
references: Am J Physiol Renal Physiol. 2005 Feb;288(2):F327-33
references: 15454390
references: FEBS J. 2009 Dec;276(23):7016-26
references: 19878299
references: Theor Biol Med Model. 2007 Sep 06;4:33
references: 17803828
references: J Biol Chem. 2000 Dec 15;275(50):39617-24
references: 10978330
references: Nat Genet. 2006 Mar;38(3):324-30
references: 16444273
references: J Biol Chem. 1994 Nov 11;269(45):27807-10
references: 7961706
references: J Biol Chem. 2001 May 4;276(18):14972-9
references: 11279063
references: Endocr Relat Cancer. 2008 Mar;15(1):125-38
references: 18310281
references: Neuroscience. 2006;137(4):1247-57
references: 16359813
references: Curr Drug Metab. 2011 Mar;12(3):268-77
references: 21470105
references: Mol Pharmacol. 2005 Feb;67(2):545-57
references: 15537867
references: Bioorg Med Chem Lett. 2008 Jun 15;18(12):3481-3
references: 18513968
references: J Biol Chem. 2006 Jan 6;281(1):43-50
references: 16230346
references: J Invest Dermatol. 2010 Feb;130(2):529-40
references: 19710689
references: FEBS Lett. 2007 Mar 6;581(5):935-8
references: 17303126
references: J Mol Graph. 1996 Feb;14(1):33-8, 27-8
references: 8744570
references: Mol Pharmacol. 2008 Oct;74(4):964-71
references: 18612080
references: Nature. 2006 Sep 14;443(7108):180-5
references: 16943773
references: Eur J Med Chem. 2008 Nov;43(11):2557-67
references: 18313803
references: J Comput Chem. 2005 Dec;26(16):1781-802
references: 16222654
references: J Biol Chem. 1994 Mar 11;269(10):7243-8
references: 7907326
references: J Biol Chem. 2003 Aug 8;278(32):29509-14
references: 12764137
references: Mol Pharmacol. 2004 Jun;65(6):1375-85
references: 15155831
references: J Mol Biol. 1996 Aug 23;261(3):470-89
references: 8780787
references: Pflugers Arch. 2007 Feb;453(5):675-84
references: 16868766
references: Hum Genet. 2007 Jun;121(5):631-3
references: 17394018
references: Breast Cancer Res. 2004;6(3):R252-63
references: 15084249
references: Science. 2009 Mar 27;323(5922):1718-22
references: 19325113
references: FASEB J. 2009 Jun;23(6):2001-13
references: 19383836
references: Structure. 1999 Mar 15;7(3):R55-60
references: 10368306
references: Mol Cancer Ther. 2007 Jan;6(1):122-7
references: 17237272
references: Clin Cancer Res. 2009 Mar 1;15(5):1762-9
references: 19240178
references: Pharmacogenetics. 2002 Jun;12(4):321-30
references: 12042670
references: Breast Cancer Res Treat. 2006 Sep;99(1):9-17
references: 16752223
references: J Biol Chem. 2002 Jun 7;277(23):20934-41
references: 11925441
references: Mol Med. 2001 Aug;7(8):509-16
references: 11591886
references: J Biol Chem. 2004 Sep 10;279(37):38871-80
references: 15208328