Researchers studied special peptides made by mushrooms that are processed by fungal enzymes called KEX2 and KEX1. They developed a method to find and identify these peptides in mushroom tissues and confirmed they exist in both laboratory and edible mushroom species like shiitake and oyster mushrooms. When they removed the genes for these processing enzymes, the mushrooms had problems growing and forming fruiting bodies, suggesting these enzymes have important roles beyond just processing these specific peptides.