Dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1B (DYRK1B) belongs to a family of nuclear-localized protein kinases and participates in the regulation of the cell cycle with key roles in proliferation and differentiation. It is upregulated in solid tumors and gain-of-function mutations in the gene encoding this kinase have been linked to metabolic syndrome. AZ191 is a cell-permeable azaindole that inhibits the serine/threonine kinase activity of DYRK1B (IC50 = 17 nM) with 5-fold and 110-fold selectivity against the related family members DYRK1A and DYRK2, respectively. This compound has been used as a probe to elucidate the mechanism of DYRK1B regulation of cell cycle progression.{28993
