page_title: Melanocortin 1 receptor
section_title: Some roles in development
hierarchical_section_title: Melanocortin 1 receptor / Functions / Some roles in development
caption_attribution_description: English: MCR1 deficiency and osteoarthritis
context_page_description: The melanocortin 1 receptor, also known as melanocyte-stimulating hormone receptor, melanin-activating peptide receptor, or melanotropin receptor, is a G protein–coupled receptor that binds to a class of pituitary peptide hormones known as the melanocortins, which include adrenocorticotropic hormone and the different forms of melanocyte-stimulating hormone.
  MC1R is one of the key proteins involved in regulating mammalian skin and hair color. It is located on the plasma membrane of specialized cells known as melanocytes, which produce the pigment melanin through the process of melanogenesis. It works by controlling the type of melanin being produced, and its activation causes the melanocyte to switch from generating the yellow or red phaeomelanin by default to the brown or black eumelanin in replacement.
  MC1R has also been reported to be involved in cancer, developmental processes, and susceptibility to infections and pain.
context_section_description: Since G protein–coupled receptors are known to activate Signal transduction in cells, it should not be surprising to find MC1R involved in development. As one example at the cellular level, preventing signalling by MC1R stopped erythropoiesis from proceeding from the polychromatic cell stage (poly-E in the figure) to the orthochromatic cell stage (ortho-E in the diagram). The same report showed that neutralizing antibodies to MC1R prevented phosphorylation of STAT5 by erythropoietin, and that MC2R and MC5R were also involved, as shown in their model.
  One example at the tissue level showed the involvement of MC1R in the normal and pathological development of articular cartilage in the mouse knee. In this study the authors compared normal mice with mice completely lacking MC1R. Even without experimental induction of osteoarthritis, mice without MC1R had less articular cartilage (as shown by the red staining in the image). After experimental induction of osteoarthritis, the defect caused by MC1R was more pronounced.
caption: MC1R deficiency and osteoarthritis
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