Plasmin cleavage of β2-glycoprotein I alters its structure and ability to bind to pathogenic antibodies.

Summary: In a condition called Antiphospholipid Syndrome (APS), the immune system mistakenly attacks a blood protein called β2GPI. Normally, this protein is shaped like a "J" or a circle. However, researchers have discovered that when a specific enzyme called plasmin interacts with β2GPI, it cuts the protein and twists it into a completely new "S" shape. This structural change acts like a beacon, causing the body's harmful antibodies to bind to the protein more aggressively. Understanding this "S" shape helps explain how the disease progresses and why the immune attack is so severe.