Membrane Protein Arrays: Application for GPCR Screening

Transcription

1 Membrane Protein Arrays: Application for GPCR Screening Ye Fang, Anthony G. Frutos, Brian L. Webb, Yulong Hong, Fang Lai, Laurent Picard and Joydeep Lahiri. Corning Incorporated, Corning, NY, USA

2 G proteincoupled receptors (GPCR) arrays GPCRexpressing biological membranes G Ligand binds specifically to GPCR immobilized on surface Array Printing on optimized substrate Spot Ø: 15 m Spot pitch: 2 m Incubation Image Array 1 Adrenergic Receptor: Bodipy TMRCGP Broad IP coverage expected. Fang, Y. et al. J. Am. Chem. Soc. 22, 124, 2394.

3 Manufacturing feasibility Slide 1 Grid 6 Slide 3 Grid 41 Slide 5 Grid 68 2A 1 2 GPCR array printing capabilities: 5 slides x 16 grids per slide x 4 duplicate spots of each sample printed per grid = 32 spots printed with a single sample pickup ~1 nl membranes per spot Printing Reproducibility: Intraslide CV = 1% Interslide CV < 2% Binding Reproducibility: CV = 14.5% 3

4 Saturation assay Neurotensin Receptor (NTR1) RFU 4 2 Specific BTNT BTNT 2 M NT Specific Total [BTneurotensin] (nm) BT = BodipyTMR [BTNT] (nm) RFU 4 2 Nonspecific [BTneurotensin] (nm) RFU/[BTNT] 3 15 Kd= 1.3 nm RFU (specific) 4 Conclusions: The receptors in the arrays retain ligand binding activity. GPCR arrays can be used to estimate ligand affinity.

5 Competitive binding assay Neurotensin Receptor (NTR1) 9 Positive control 2 nm BTneurotensin [neurotensin] (nm) RFU 6 3 N Neuromedin N NTR1 Neurotensin [Inhibitor] (nm) BT = BodipyTMR Conclusions: Competition assays can be performed with GPCR arrays. Neurotensin Neuromedin N IC nm 25 nm K i 1.2 nm 16.3 nm 5 GPCR arrays can be used to assess potency of compounds and measure their IC 5.

6 Ligand binding specificity Array of distinct family receptors Negative Control Positive Control BTneurotensin (2 nm) 1 nm CGP SCH2339 neurotensin 16 1 NTR1 D1 RFU NTR1 D1 adrenergic receptor 1 ( 1) Neurotensin receptor 1 (NTR1) Dopamine receptor 1 (D1) = No inhibition = Inhibition i ii iii iv v Conclusions: The binding of BTNT to NTR1 in the array is specific. Neurotensin can specifically compete with BTNT. Nonspecific compounds do not compete. GPCR arrays precomplexed with labeled ligands can be used for compound screening (displacement assay not shown).

7 Selectivity screening Adrenergic receptors BTCGP12177 Intensity AR 2 AR CGP.6 nm.6 nm ICI 1.2 nm 12 nm Positive control 5nM CGP nM ICI A Beta 1 Beta 2 Alpha2A Conclusions: BTCGP can specifically bind to 1 and 2, but not 2A receptors on the array. ICI is a 2selective antagonist. GPCR arrays can be used for selectivity screening of compounds among the different subtypes of a receptor family. 7

8 Microplatebased GPCR arrays BTCGP (2 nm) BTCGP (2 nm) 1 M cold CGP 3x3 array of ADR B1 in each well RFU BTCGP (2 nm) BTCGP (2 nm) 1 M cold CGP 8

9 sulinda U73122 W84 vancomycin W84 ZD 7155 GTP GDP GTP GTPbS GTPvS substance P NF23 NF449 GTPbS GTPbS SCH2339 suramine clonidine Compound screening 1 adrenergic receptor CV 13% () average Compound RFU 65% inhibition () average SCH2339 angiotensin naloxone II L naloxone pirenzepine naltrexone Neurotensin pirenzepine saralasin quinpirole RGD Low affinity ligands Gprotein activator Gprotein antagonist betaxolol betaxolol CGP CGP epinephrine epinephrine ICI ICI propranolol propranolol salbutamol salbutamol xamoterol xamoterol acetaminophen biotin bromoenol cisplatin clozapine dynorphin A113 glutamic acid neurokinin A neuromedin N neuroteinsin 111 neuroteinsin 813 nociceptin113 NF23 nonbinaltorphimine Orphain FQ oxymetazoline NF7 sulinda RGD1 saralasin No BTCGP 2 nm BTCGP Unknowns (1 M) Known inhibitors (1 M) Known noninhibitors (1 M)

10 Product concepts and applications Multiplex GPCR assays In microplates Virtual microplates On glass slide 1 Highthroughput primary screening Compound selectivity profiling An alternative to microplates in which slide are scanned independently Broad screening of GPCRs: identify ligands, activators, test mutants, protein binding Pattern recognition in complex mixtures

11 Multiplex screening and compound profiling GPCR panel arrayed in 96 or 384 well plates. Suitable for HTS and compound profiling. Customizable content proprietary receptor content screening public receptor panel selectivity Direct binding or competition assay. Fluorescent or radioactive compounds. Functional assay under development on the same platform. 11

12 Technology Access Program Who? Pharmas and Biotech drug discovery companies Screening service companies What do we offer? Collaboration on customized GPCR array products Early access to IP and GPCR array technology Licensing Why? Save on membrane and reagent costs Permits higherquality screens: multiplexing Selectivity profiles: efficacy vs. toxicity Amenable to HTS Transposable to other membrane targets 12

13 Key results GPCR arrays can be fabricated: Broad IP coverage expected Fang, Y. et al. J. Am. Chem. Soc. 22, 124, 2394 Mechanically stable, receptors show lateral fluidity. Can be stored Binding of labeled ligands to receptors in the arrays is saturable. Can be used for quantitatively measuring compound binding affinity. Can be used for compound selectivity screening. Slides and microplatebased assays are possible. 13