ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with PDLIM1/CLP-36. When associated with PDLIM1, it is mostly found in cytoplasm, localized to actin stress fibers (PubMed:11973348). However, PubMed:19756140 detected STK35 only in the nucleus, and the presence of PDLIM1 had no influence on its location. Expressed in testis. Autophosphorylated. Association with PDLIM1 is controversial. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus.