Involved in fetal development, T-cell function and adrenal gland growth homeostasis (PubMed:28169274). Negatively regulates adrenal cells survival. Plays a role in steroidogenesis, modulates steroidogenic enzymes expression and cortisol production (By similarity). Expression is high in the thymus, stomach, bone marrow and lymphatic tissues (including lymph nodes and intestinal wall). Also expressed in the adrenal gland, skin and in brain structures, with noticeable levels found in the cerebellum. In CD4(+) T-cells, mRNA expression is induced 2h after CD3E plus CD28 stimulation, then subsides and remains low between 24 and 72h post-activation. Embryonic lethality, with its severity depending on genetic background of the mice: embryonic lethality becomes more severe with higher degrees of genetic background purity (PubMed:28169274). Knockout mice are small in body size. They have compromised T-cell proliferation and differentiation into Th1 and Th17 cells, increased T-cell apoptosis, reduced severity of experimental autoimmune encephalitis, and defective immune responses to lymphocytic choriomeningitis virus infection. They develop adrenal gland hyperplasia in old age (PubMed:28169274). Extended N-terminus. Truncated N-terminus.