How does the synthesis of melanin by melanocytes help? Melanocytes synthesize melanin by forming a protective covering over the nucleus of the skin cells in order to protect the DNA of the skin. In addition to that, melanin absorbs UV and protects the folate in the circulatory system under the skin.
Melanin is a natural pigment occurring in the body produced in specialized cells called melanocytes. Melanin has a major role in protecting the body from the harmful effects of UV radiation.
Key Areas Covered
1. What is Melanin
– Definition, Features, Importance
2. What are Melanocytes
– Definition, Features, Importance
2. How Does the Synthesis of Melanin by Melanocytes Help
– Features, Importance
Key Terms
Melanin, Melanocytes
What is Melanin
Melanin is a natural pigment produced by the specialized cells called melanocytes. The five basic types of melanin include eumelanin, pheomelanin, neuromelanin, allomelanin, and pyomelanin. Among them, eumelanin is the most common type of melanin. Brown eumelanin and black eumelanin are the two types of eumelanin. Also, melanogenesis is the process of producing eumelanin. It undergoes the oxidation of the amino acid, L-tyrosine, following polymerization. When the genes undergo malfunctioning, the synthesis of pheomelanin occurs. Pheomelanin is a recessive form of eumelanin and is responsible for red or yellow skin and hair color. Apart from that, neuromelanin occurs in the brain. The other two types of melanin, the allomelanin and pyomelanin, are nitrogen-free melanin.
Figure 1: Eumelanin
Furthermore, melanogenesis initiates in the human skin upon exposure to UV radiation. This causes the skin to become dark. Therefore, melanin serves as the primary determinant of skin color. Excluding the skin, melanin also occurs in the hair, the stria vascularis of the inner ear, and the pigmented tissue underlying the iris of the eye. In addition, the medulla and the pigmented areas of the brainstem contain melanin. The zona reticularis of the adrenal gland contains melanin too.
What are Melanocytes
Melanocytes are the cells specialized for the production of melanin. They occur in the basal layer of the epidermis. Normally, human beings have a similar concentration of melanocytes in the skin. Melanocytes migrate to the epidermis from the neural crest during embryonic development. Melanocytes are dendritic cells. The main function of melanocytes is to produce melanin.
Figure 2: Melanocytes
How Does the Synthesis of Melanin by Melanocytes Help
Melanin is a pigment occurring in the skin that serves as protection against UV radiation. Melanogenesis is the process of producing melanin. It occurs in the basal layer of epidermal cells. Therefore, eumelanin and pheomelanin are the two main types of melanin, and they are the final products of complex biochemical reactions. The main role of melanin is to involve in skin homeostasis by providing photoprotection. This means it offers the harmful effects of UV radiation. Hence, melanin absorbs and reflects UV radiation while neutralizing free radicals and reactive oxygen species. The two factors of melanogenesis are intrinsic factors such as hormones and genetic factors, and extrinsic factors such as exposure to UV radiation. Adrenocorticotropin, stimulant melanocytic hormone, estrogen, and progesterone are the hormones that stimulate the production of melanin.
Furthermore, exposure to UV radiation influences the function as well as the survival of cell types, while it can induce skin cancer formation. Therefore, skin pigmentation is the most important photoprotective factor that protects the skin from UV radiation. Melanin absorbs UV radiation. It has radical scavenging properties while serving as an antioxidant. However, the main function of melanin is to protect the DNA of the skin, forming a protective covering over the nucleus of the skin cells, and it protects folate in the blood under the skin by absorbing UV radiation.
Conclusion
In brief, melanin is a natural pigment that determines the skin color. There are five types of melanin. Among them, eumelanin and pheomelanin are the major types of melanin. In addition, eumelanin is responsible for the light and dark shades of the skin. Meanwhile, pheomelanin is responsible for the red and yellow colors. On the other hand, melanocytes are the specialized type of cells that produce melanin. Also, melanogenesis is the process of producing melanin. The basal layer of the skin produces melanin. Importantly, the melanin absorbs UV radiation. Therefore, it protects the skin from UV radiation. And, thus, it prevents skin cancer formation. Apart from that, melanin can protect the DNA of the skin by providing a protective layer around the nucleus. It also absorbs UV radiation by protecting the folate in the bloodstream in the skin. Therefore, melanin is important for protecting against UV radiation.
References:
- Maranduca MA, Branisteanu D, Serban DN, Branisteanu DC, Stoleriu G, Manolache N, Serban IL. Synthesis and physiological implications of melanic pigments. Oncol Lett. 2019 May;17(5):4183-4187. doi: 10.3892/ol.2019.10071. Epub 2019 Feb 25. PMID: 30944614; PMCID: PMC6444329.
Image Courtesy:
- “Eumelanine” By Roland Mattern – Own work (Public Domain) via Commons Wikimedia
- “Illu skin02” By Unknown – Own Work (Public Domain) via Commons Wikimedia
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