Isoform 2 is a receptor for IL22. Binds to IL22, prevents interaction with the functional IL-22R complex and blocks the activity of IL22 (in vitro). May play an important role as an IL22 antagonist in the regulation of inflammatory responses. Isoform 1 may play a role in establishing and maintaining successful pregnancy. Expressed in placenta, spleen, breast, skin and lung. Also detected in intestinal tract, testis, brain, heart and thymus. No expression found in prostate, bladder, kidney, ovary, muscle, bone marrow, liver and uterus. Isoform 1 is expressed only in placenta. Isoform 2 is expressed in placenta and breast and at lower level in spleen, skin, thymus and stomach. Belongs to the type II cytokine receptor family.