Acquiring maternal immunoglobulin; different receptors, similar functions.

The isolation of a novel Fc receptor (FcRY) from chicken yolk sac provides insight at the mechanistic level as to how avian maternal immunoglobulin (IgY) is transferred to offspring. This receptor is distinct from its mammalian counterpart and is a phospholipase A(2) receptor homolog. Biophysical analyses indicate that FcRY achieves pH-dependent binding to IgY through a conformational change.