β₂ microglobulin is a component of MHC class I molecules, which are present on almost all cells of the body (red blood cells are a notable exeption). β₂ microglobulin lies lateral to the α₃ chain on the cell surface, however unlike α₃, β₂ has no trans-membrane region. Directly above β₂ (i.e. away from the cell) lies the α₁ chain, which itself is lateral to the α₂.

In patients on long-term hemodialysis, it can aggregate into amyloid fibers that deposit in joint spaces, a disease known as dialysis-related amyloidosis.

Proteins

Cell biology