STE20-related kinase adapter protein alpha isoform 5, also known as STRADA, is a member of STE-20 like kinase family are known to stimulate MAPK pathways by directly activating MAPKKK. It functions as an upstream activator of LKB1 and also directs the sub-cellular localization of LKB1 by anchoring it in the cytoplasm. STRADA-LKB1 interaction results in phosphorylation of STRADA and enhanced autophosphorylation of LKB1. Recombinant human STRADA protein, fused to His-tag at N-terminus, was expressed in E.coli.