Protease-inhibitor that contains multiple distinct protease inhibitor domains. Probably has serine protease- and metalloprotease-inhibitor activity. Inhibits the biological activity of mature myostatin, but not activin (By similarity).
Subcellular locations: Secreted
Primarily expressed in ovary, testis and brain, but not in liver. In fetal tissues, it is primarily expressed in brain, skeletal muscle, thymus and kidney.