Human Insulin Receptor (ISR) ELISA Kit

Principle of the Assay

The test principle applied in this kit is Sandwich enzyme immunoassay. The microtiter plate provided in this kit has been pre-coated with an antibody specific to Human ISR. Standards or samples are added to the appropriate microtiter plate wells then with a biotin-conjugated antibody specific to Human ISR. Next, Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. After TMB substrate solution is added, only those wells that contain Human ISR, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450nm ± 10nm. The concentration of Human ISR in the samples is then determined by comparing the OD of the samples to the standard curve.

For use with: Tissue homogenates, cell lysates, cell culture supernates, and other biological fluids.

For Research Use Only. Not for use in diagnostic procedures.

Target Information

Receptor tyrosine kinase which mediates the pleiotropic actions of insulin. Binding of insulin leads to phosphorylation of several intracellular substrates, including, insulin receptor substrates (IRS1, 2, 3, 4), SHC, GAB1, CBL and other signaling intermediates. Each of these phosphorylated proteins serve as docking proteins for other signaling proteins that contain Src-homology-2 domains (SH2 domain) that specifically recognize different phosphotyrosine residues, including the p85 regulatory subunit of PI3K and SHP2. Phosphorylation of IRSs proteins lead to the activation of two main signaling pathways: the PI3K-AKT/PKB pathway, which is responsible for most of the metabolic actions of insulin, and the Ras-MAPK pathway, which regulates expression of some genes and cooperates with the PI3K pathway to control cell growth and differentiation. Binding of the SH2 domains of PI3K to phosphotyrosines on IRS1 leads to the activation of PI3K and the generation of phosphatidylinositol-(3, 4, 5)-triphosphate (PIP3), a lipid second messenger, which activates several PIP3-dependent serine/threonine kinases, such as PDPK1 and subsequently AKT/PKB. The net effect of this pathway is to produce a translocation of the glucose transporter SLC2A4/GLUT4 from cytoplasmic vesicles to the cell membrane to facilitate glucose transport. Moreover, upon insulin stimulation, activated AKT/PKB is responsible for: anti-apoptotic effect of insulin by inducing phosphorylation of BAD; regulates the expression of gluconeogenic and lipogenic enzymes by controlling the activity of the winged helix or forkhead (FOX) class of transcription factors. Another pathway regulated by PI3K-AKT/PKB activation is mTORC1 signaling pathway which regulates cell growth and metabolism and integrates signals from insulin. AKT mediates insulin-stimulated protein synthesis by phosphorylating TSC2 thereby activating mTORC1 pathway. The Ras/RAF/MAP2K/MAPK pathway is mainly involved in mediating cell growth, survival and cellular differentiation of insulin. Phosphorylated IRS1 recruits GRB2/SOS complex, which triggers the activation of the Ras/RAF/MAP2K/MAPK pathway. In addition to binding insulin, the insulin receptor can bind insulin-like growth factors (IGFI and IGFII). Isoform Short has a higher affinity for IGFII binding. When present in a hybrid receptor with IGF1R, binds IGF1. PubMed:12138094 shows that hybrid receptors composed of IGF1R and INSR isoform Long are activated with a high affinity by IGF1, with low affinity by IGF2 and not significantly activated by insulin, and that hybrid receptors composed of IGF1R and INSR isoform Short are activated by IGF1, IGF2 and insulin. In contrast, PubMed:16831875 shows that hybrid receptors composed of IGF1R and INSR isoform Long and hybrid receptors composed of IGF1R and INSR isoform Short have similar binding characteristics, both bind IGF1 and have a low affinity for insulin. In adipocytes, inhibits lipolysis (By similarity).

GENE ID	3643
SWISS PROT	P06213
SYNONYMS	CD220; INSR; HHF5; IR; Insulin receptor subunit beta; Insulin Receptor beta

Materials Supplied

Kit Components	96 Wells Quantity/Size
Pre-Coated Microplate	48T: 6 strips x 8 wells; 96T: 12 strips x 8 wells
Standard (Lyophilized)	48T: 1 vial; 96T: 2 vials
Biotinylated Antibody (100×)	48T: 60 μL; 96T: 120 μL
Streptavidin-HRP (100×)	48T: 60 μL; 96T: 120 μL
Standard/Sample Diluent Buffer	48T: 10 mL; 96T: 20 mL
Biotinylated Antibody Diluent	48T: 6 mL; 96T: 12 mL
HRP Diluent	48T: 6 mL; 96T: 12 mL
Wash Buffer (25×)	48T: 10 mL; 96T: 20 mL
TMB Substrate Solution	48T: 6 mL; 96T: 10 mL
Stop Reagent	48T: 3 mL; 96T: 6 mL
Plate Covers	48T: 1 piece; 96T: 2 pieces

Storage

Storage

*If the kit is opened, Store the whole kit at 4°C. If the kit is not used up in 1 week. Store the Pre-Coated Microplate, Standard ,Biotinylated Antibody and Streptavidin-HRP at -20°C, the rest reagents at 4°C, please used up within 6 months. *If the kit is not opened, store the whole kit: 4°C(short time storage, valid for 6 months); -20°C (long-term storage, valid for 1 year). Avoid repeated freeze-thaw cycles.

Performance Characteristics

REPEATABILITY	Intra-assay Precision (Precision within an assay)：CV% < 8% Three samples of known concentration were tested twenty times on 1 plate to assess intra-assay precision. Inter-assay Precision (precision between assays)：CV% < 10% Three samples of known concentration were tested in forty separate assays to assess inter-assay precision.
SENSITIVITY	The minimum detectable dose was 0.54ng/mL.
ASSAY RANGE	1.57–100ng/mL
SPECIFICITY	This assay has high sensitivity and excellent specificity for detection of Human ISR. No significant cross-reactivity or interference between Human ISR and analogues was observed.