Screening method for an insulin resistance improving agent or a therapeutic agent for diabetes
A new compound inhibiting phosphorylation of Ser727 of STAT3, a phosphorylation inhibitor containing the new compound, an insulin resistance improving agent and a preventive or therapeutic agent for diabetes; and a screening method for at least one of the insulin resistance improving agent and the preventive or therapeutic agent for diabetes.
1. A screening method for at least one of an insulin resistance improving agent and a therapeutic agent for diabetes, the screening method comprising:
determining the presence or absence of interaction between signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase 2 (ERK2) to select a compound having a phosphorylation inhibitory activity, and
evaluating the compound for whether X>Y where X denotes a Homeostasis model assessment-Insulin Resistance (HOMA-IR) value of a diabetes model animal to which the compound has not been administered and Y denotes a HOMA-IR value of a diabetes model animal to which the compound has been administered,
wherein the determining is performed by preparing a mixture by mixing together at least the compound, the STAT3 whose Ser727 is not phosphorylated, and an enzyme that phosphorylates the STAT3; reacting the STAT3 whose Ser727 has been phosphorylated in the mixture with an antibody that binds to a phosphorylated site of the STAT3 whose Ser727 has been phosphorylated; and screening for the compound present in the mixture containing the STAT3 to which the antibody has not bound, as a compound having the phosphorylation inhibitory activity.
2. The screening method according to claim 1 , wherein the preparing comprises phosphorylating the Ser727 of the STAT3 contained in the mixture.
3. The screening method according to claim 1 , wherein the reacting comprises detecting the antibody binding to the phosphorylated site of the STAT3 whose Ser727 has been phosphorylated.
4. The screening method according to claim 3 , wherein the detecting is performed with IgG derived from a host of the antibody binding to the phosphorylated site of the STAT3 whose Ser727 has been phosphorylated.
5. The screening method according to claim 4 , wherein the IgG is detected with a label bound thereto.
6. The screening method according to claim 1 , wherein the screening is performed by determining the presence or absence of the phosphorylation inhibitory activity of the compound.