Melanocyte
As shown in this lovely diagram, melanocytes are cells found in the bottom part of our epidermis, or the layer closest to the top of the skin (1). They are eukaryotic, meaning that they have a nucleus (shown in dark purple), many linear DNA chromosomes within the nucleus that are basically a “how to make YOU” recipe, and membrane-bound organelles.
Melanin
Like most of our cells, melanocytes perform a very special(ized) function: they are where melanin is made! Melanin is the pigment that gives us our beautiful color. There is a misconception that the more melanocytes we have, the darker our skin color is. If there is one thing that unites us as one big happy family, it is that we all have roughly the same number of melanocytes. The difference is the amount of pigment we make – the more melanin, the darker our skin color (1).
Melanin also functions to protect us from everyone’s arch-nemesis: the sun’s harmful UV rays (yes we all hate you but still have to bring you up in this very blog…) (1). An example is that I have olive skin and my close friends have pale skin, so they get sunburned a lot easier than I do (sorry, anonymous close friends).
Melanosome
Melanosomes are organelles within melanocytes that make melanin. Once they are full of pigment, they move out of the melanocyte and into nearby keratinocytes with the help of structures called dendrites. This business transaction between melanocytes and keratinocytes allows for our skin to be properly controlled (1).
Other Organelles
We already mentioned that melanocytes have a nucleus and melanosomes, but they also have a rough endoplasmic reticulum (ER), mitochondria, a Golgi apparatus (1), and vesicles (2). The rough ER houses ribosomes, and ribosomes make proteins. The enzyme tyrosinase, which we will discuss about in the next post, is a protein that melanocytic ribosomes make. Vesicles help to move tyrosinase from the rough ER to the Golgi apparatus, where they are packaged and modified. After that, more vesicles help to move them out of the Golgi to fuse with the melanosomes so that they can aid in the melanin-making process (2).
References
- Costin, G.-E., & Menon, G. K. (2018, January 15). Know Your Skin Cells: III. The Melanocytes. The Cosmetic Chemist. http://www.thecosmeticchemist.com/education/skin_science/know_your_skin_cells_iii_the_melanocytes.html
- Cox, G. F., & Fulton, A. B. (2010). Albinism. Ocular Disease, 461–471. https://doi.org/10.1016/b978-0-7020-2983-7.00060-7