BI-D1870

BI-D1870 inhibits RSK1, RSK2, RSK3 and RSK4 with an IC50 of 10–30 nM, but does not significantly inhibit ten other AGC kinase members and over 40 other protein kinases tested at 100-fold higher concentrations. BI-D1870 is cell permeant and prevents the RSK-mediated phorbol ester- and EGF -induced phosphorylation of glycogen synthase kinase-3β and LKB1 in human embry-onic kidney 293 cells and Rat-2 cells. BI-D1870 does not affect the agonist-triggered phosphorylation of substrates for six other AGC kinases. Moreover, BI-D1870 does not suppress the phorbol ester- or EGF-induced phosphorylation of CREB. ^[1]

• Protein kinase assays

  Purified His6–RSK1, His6–RSK2 or GST–RSK2 ^{1–389:S381E} (1–2 units/mL) are assayed for 10 min at 30 °C in a 50 μL assay mixture in Buffer A containing 30 μM substrate peptide (KEAKEKRQEQIAKRRRLSSLRASTSKSGGSQK), 10 mM magnesium acetate and 100 μM of [γ-³²P]ATP. Reactions are terminated and analysed as described previously. The amount of enzyme that catalysed the phosphorylation of 1 nmol of substrate peptide in 1 min is termed one unit. In order to assay RSK and MSK1 in HEK-293 or Rat-2 cell lysates, these kinases are immunoprecipitated from the cell lysates (0.1 mg of lysate protein for RSK and 0.3 mg for MSK1) and for RSK assays the immunoprecipitates are washed twice with Buffer A containing 1 mM ATP and twice with Buffer A prior to the assay, as a precaution to ensure dissociation of BI-D1870 from the RSK isoforms.

• Animal Models

  C57/BL6J mice

• Dosages

  0.5 mg/kg

• Administration

  i.p.