KT5823, a selective the cGMP-dependent protein kinase (PKG) inhibitor with an K_i value of 0.23 μM, it also inhibits PKA and PKC with K_i values of 10 μM and 4 μM, respectively^[1]. KT5823 is a staurosporine-related protein kinase inhibitor, increases thyroid-stimulating hormone-induced (Na⁺/I^- symporter) NIS expression, and iodide uptake in thyroid cells^[2]. KT5823 arrests cells after the G0/G1 boundary and causes increases in the levels of apoptotic DNA fragmentation^[3]. IC50 & Target: Ki: 0.23 μM (PKG); 10 μM (PKG); 4 μM (PKG) (KT5823)^[1]