Enables protein kinase binding activity and protein serine/threonine kinase activity. Involved in epithelial tube morphogenesis; hyperosmotic response; and multicellular organismal-level water homeostasis. Acts upstream of with a positive effect on positive regulation of gene expression. Located in cytoplasm. Expressed in body wall musculature; excretory system; hypodermis; oocyte; and spermatheca. Is an ortholog of human OXSR1 (oxidative stress responsive kinase 1) and STK39 (serine/threonine kinase 39).