Human STK3 (serine/threonine kinase 3), also known as MST-2 (Mammalian STE20-like protein kinase 2) or KRS1, GenBank Accession No. NM_006281, a.a. 2-492(end), with N-terminal GST-tag, MW=78.4 kDa, expressed in Sf9 insect cells via a baculovirus expression system.