Immunity: IgM mechanism (Introduction)

by David Turell , Wednesday, October 10, 2018, 19:25 (2026 days ago) @ David Turell

Immune globulins are giant protein molecules which fight general infections. IgM has a unique mechanism to release another smaller fighting protein molecule:

https://phys.org/news/2018-10-pentagon-beanredrawing-immune-protein.html

"Researchers verified the structure of natural immunoglobulin M (IgM) protein, an important part of the immune system, using mouse and human versions of the protein. IgM is now understood to be shaped like an incomplete hexagon, or a pentagon with a wedge-shaped gap.

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"IgM is the first immune system protein that develops in the human fetus and remains the first responder to pathogens throughout life. The structure of IgM was first identified in 1969 as a "five-pointed, star-shaped table" and updated in 2009 to be a five-sided dome or "mushroom cap."

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"The 2018 discovery of the incomplete hexagon was actually a secondary interest for Miyazaki, originally a medical doctor who has built his research career studying a different protein called apoptosis inhibitor of macrophage (AIM).

"Since identifying the correct shape of IgM, researchers now understand that inactive AIM is nestled inside the gap of the IgM incomplete hexagon. The structural connection between IgM and AIM means that drugs with the ability to regulate the release of AIM could be used to create AIM-based disease therapies.

"'We can think of AIM as a fighter jet and IgM as the aircraft carrier ship. When other molecules activate the immune system, IgM releases AIM. The much smaller AIM protein goes around the body to clear away damaged cells and prevent disease," said Miyazaki.

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"AIM is a common molecule in the bloodstream, but it is only active when the body develops a disease. AIM is known to be important for preventing obesity, fatty liver disease, hepatocellular carcinoma (liver cancer), multiple sclerosis (MS), fungus-induced peritonitis (inflammation of the abdominal wall membrane), and acute kidney injury."

Comment: Note the importance of IgM as the first forming immune globulin in the fetus. How AIM and Igm worked out their arrangement of hold and release is not a result of chance. Note my bold.