Pseudokinase which, in complex with CAB39/MO25 (CAB39/MO25alpha or CAB39L/MO25beta), binds to and activates STK11/LKB1. Adopts a closed conformation typical of active protein kinases and binds STK11/LKB1 as a pseudosubstrate, promoting conformational change of STK11/LKB1 in an active conformation. {ECO:0000269|PubMed:12805220, ECO:0000269|PubMed:14517248, ECO:0000269|PubMed:19892943}. This is the function of STRADA (STE20 related adaptor alpha, Ensembl gene identifier ENSG00000266173).