G-protein coupled receptor for CRH (corticotropin-releasing factor) and UCN (urocortin). Has high affinity for CRH and UCN. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and down-stream effectors, such as adenylate cyclase. Promotes the activation of adenylate cyclase, leading to increased intracellular cAMP levels. Inhibits the activity of the calcium channel CACNA1H. Required for normal embryonic development of the adrenal gland and for normal hormonal responses to stress. Plays a role in the response to anxiogenic stimuli. Heterodimer; heterodimerizes with GPER1 (By similarity). Interacts (via N-terminal extracellular domain) with CRH and UCN. Interacts with DLG1; this inhibits endocytosis of CRHR1 after agonist binding. Agonist-binding promotes endocytosis. Detected in brain cortex (at protein level). The transmembrane domain is composed of seven transmembrane helices that are arranged in V-shape. Transmembrane helix 7 assumes a sharply kinked structure (By similarity). C-terminal Ser or Thr residues may be phosphorylated. Phosphorylation at Ser-301 by PKA prevents maximal coupling to Gq-protein, and thereby negatively regulates downstream signaling. Heterozygous mice are fertile and produce homozygous pups at the expected Mendelian rate, but about 15% of the homozygous males die between 3 and 12 weeks after birth. Mice are deficient in CRF-mediated secretion of ACTH and show no increase in intracellular cAMP levels in response to CRF. Mice display a marked decrease in the size of the zona fasciculata of the adrenal gland, where corticosterone is produced, and have very low plasma corticosterone levels. Mutant mice display reduced anxiety. They fail to produce increased levels of ACTH and corticosterone in response to stress, contrary to wild type mice. Homozygous mice are fertile, but almost all of the pups die within 48 hours after birth, due to defects in lung inflation and alveolar collapse. Treatment of pregnant females with corticosterone-containing drinking water results in normal lung maturation and normal survival of their progeny. Belongs to the G-protein coupled receptor 2 family.