Anti-STK4 antibodies are used in the immunodetection of the protein serine/threonine kinase 4. In humans, the canonical protein has a reported length of 487 amino acid residues and a mass of 55.6 kDa. Its subcellular localization is in the nucleus and cytoplasm. Up to 2 different isoforms have been reported for this protein. It is reported to be expressed in prostate cancer and levels increase from the normal to the malignant state. A member of the STE Ser/Thr protein kinase protein family, STK4 is known to be involved with the apoptotic pathway and the Wnt signaling pathway. Post-translational modifications have been described, including protein cleavage and phosphorylation. Synonyms for this target antigen include MST1, YSK3, serine/threonine-protein kinase 4, STE20-like kinase MST1, hippo homolog, and KRS2. STK4 gene orthologs have been reported in the mouse, rat, bovine, chimpanzee and chicken species. Over 340 citations in the literature describe the use of STK4 antibodies in research. ELISA, Western Blot, and Immunohistochemistry are common applications for these antibodies.