Multispan’s GPCR assay kits, combined with MULTISCREEN™ GPCR stable cell lines and division-arrested cells, truly enable high throughput screening (HTS) and accelerate drug discovery. Moreover, optimized assay protocols using each kit with each cell line developed by our cell and assay experts, add tremendous value to our customer’s experimental setup. These MULTISCREEN™ cross-validated complete solutions allow Multispan experts to assay with confidence in compound screening for customers. Customers can also perform in-house screening with our reagents.
MULTISCREEN™ assay kits are developed for high sensitivity, specificity and compatibility for high throughput screening. They are amenable in highly miniaturized settings, in 384-well or higher density microplates. All of Multispan’s assay kits are NO-WASH HOMOGENEOUS assay.
MULTISCREEN™ assay kits are divided into 3 categories, addressing the 3 major and most studied GPCR cell signaling pathways. These 3 cell signaling pathways are measured by their respective intracellular second messengers: calcium, cAMP and beta-arrestin. Each of the 3 types of assay kits employs a different detection mechanism such as fluorescence, TR-FRET (Time-Resolved Fluorescence Resonance Energy Transfer) or chemiluminescence, designed to be best suited for the chemical and molecular nature of each specific second messenger being measured. The different readouts not only maximize the robustness and sensitivity of the assays, but also enable the possibility of multiplexing, ie, two assays in one well. Multiplex assays are in general much desired in HTS assays to save time and cost.
The properties of a ligand that preferentially activates or inhibits one pathway over another are described as cell signaling bias. Screening compounds for biased cell signaling may lead to selective perturbation of disease-specific pathways. Measuring compound activities in cell assays in the same cellular environment, using recombinant or native unmodified GPCRs, is key for accurate cell signaling bias analysis. Our newly developed proprietary and patented MULTISCREEN™ Beta-Arrestin recruitment assay technology overcomes the receptor-tagging drawback of other technologies, enabling high throughput detection of beta-arrestin translocation induced by native GPCRs in vitro and in vivo for the first time.
MULTISCREEN™ Beta-Arrestin assay kits provide no-wash homogeneous luminescence assays for intracellular β-Arrestin translocation detection in 96-well, 384-well and higher multiplexity. Total hands-on time for the assay is less than 30 minutes. They are suitable for any cell line or primary cells co-expressing endogenous or untagged GPCR target and MULTISCREEN™ β-Arrestin sensor introduced by viral transfections.
Calcium assay measures one of the major signaling pathways downstream of GPCRs upon ligand binding. MULTISCREEN™ Calcium No Wash Assay Kits provides homogeneous fluorescence-based assays for intracellular calcium mobilization detection in 96-well, 384-well and higher multiplexity. Pre-loaded with Calcium 1.0 dye is taken up by the cells where the lipophilic blocking groups of Calcium 1.0 are cleaved by esterases, resulting in a negatively charged fluorescent dye that stays inside cells. The fluorescence signal is greatly enhanced after binding to intracellular calcium released by cell -stimulation. Long wavelength, high sensitivity, and >100 times fluorescence enhancement make Calcium 1.0 dye an ideal indicator for intracellular calcium release assays measuring GPCRs and calcium channels. MULTISCREEN™ Calcium 1.0 No Wash Assay Kits are validated by MULTISCREEN™ stable cell lines and division-arrested cells.
cAMP assay measures another one of the major signaling pathways downstream of GPCRs upon ligand binding. MULTISCREEN™ TR-FRET cAMP No Wash Assay Kits provide a homogenous TR-FRET assay method for adenylyl cyclase activity detection in 96-well, 384-well and higher multiplexity. cAMP antibody (Ab) is labeled with MULTISCREEN™ Eu while cAMP is labeled with MULTISCREEN™ 650. In the absence of cAMP, MULTISCREEN™ 650-cAMP is bound to MULTISCREEN™ Eu-cAMP-Ab to give a strong TR-FRET emission at 655 nm. Free cAMP in the test sample competes for binding to MULTISCREEN™ Eu-cAMP-Ab, reducing TR-FRET signal from MULTISCREEN™ 650-cAMP binding. The MULTISCREEN™ 650-cAMP only has fluorescence lifetime of nanosecond while MULTISCREEN™ Eu-cAMP-Ab has much longer fluorescence lifetime value due to TR-FRET. The magnitude of TR-FRET is proportional to the concentration of cAMP in a sample. MULTISCREEN™ TR-FRET cAMP 1.0 No Wash Assay Kits are validated by MULTISCREEN™ stable cell lines and division-arrested cells.