Probable receptor with a dual specificity kinase activity acting on both serine/threonine- and tyrosine-containing substrates. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Autophosphorylated on Tyr and Thr residues. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.