Receptor for metastin (kisspeptin-54 or kp-54), a C-terminally amidated peptide of KiSS1. KiSS1 is a metastasis suppressor protein that suppresses metastases in malignant melanomas and in some breast carcinomas without affecting tumorigenicity. The metastasis suppressor properties may be mediated in part by cell cycle arrest and induction of apoptosis in malignant cells. The receptor is essential for normal gonadotropin-released hormone physiology and for puberty. The hypothalamic KiSS1/KISS1R system is a pivotal factor in central regulation of the gonadotropic axis at puberty and in adulthood. The receptor is also probably involved in the regulation and fine-tuning of trophoblast invasion generated by the trophoblast itself. Analysis of the transduction pathways activated by the receptor identifies coupling to phospholipase C and intracellular calcium release through pertussis toxin-insensitive G(q) proteins.
Subcellular locations: Cell membrane
Most highly expressed in the pancreas, placenta and spinal cord, with lower-level of expression in peripheral blood leukocytes, kidney, lung, fetal liver, stomach, small intestine, testes, spleen, thymus, adrenal glands and lymph nodes. In the adult brain, expressed in the superior frontal gyrus, putamen, caudate nucleus, cingulate gyrus, nucleus accumbens, hippocampus, pons and amygdala, as well as the hypothalamus and pituitary. Expression levels are higher in early (7-9 weeks) than term placentas. Expression levels were increased in both early placentas and molar pregnancies and were reduced in choriocarcinoma cells. Expressed at higher levels in first trimester trophoblasts than at term of gestation. Also found in the extravillous trophoblast suggesting endocrine/paracrine activation mechanism.