The major histocompatibility complex-related Fc receptor for IgG (FcRn) binds albumin and prolongs its lifespan.

Document Type


Publication Date


JAX Source

J Exp Med 2003 Feb; 197(3):315-22.


CA88053/CA/NCI, DK56597/DK/NIDDK, HD38764/HD/NICHD


The inverse relationship between serum albumin concentration and its half-life suggested to early workers that albumin would be protected from a catabolic fate by a receptor-mediated mechanism much like that proposed for IgG. We show here that albumin binds FcRn in a pH dependent fashion, that the lifespan of albumin is shortened in FcRn-deficient mice, and that the plasma albumin concentration of FcRn-deficient mice is less than half that of wild-type mice. These results affirm the hypothesis that the major histocompatibility complex-related Fc receptor protects albumin from degradation just as it does IgG, prolonging the half-lives of both.