Human skin pigmentation

Welcome to the Wikiversity learning project for human skin pigmentation. Participants explore melanin, melanosomes, melanocytes, MSH and its receptors and the control of skin pigmentation.

## Learning project organization

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This learning project is initially organized around suggested reading and discussion. Feel free to add new reading and subsections for questions and discussion.

## Melanocytes

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### Melanin biosynthesis

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Figure 1. Diagram of a melanocyte. Melanocortin receptors (MC1R) at the cell surface can respond to MSH and regulate the amount of melanin stored in melanocytes. This image is from What Controls Variation in Human Skin Color? by Gregory S. Barsh.

* Characterization of a Melanosomal Transport System in Murine Melanocytes Mediating Entry of the Melanogenic Substrate Tyrosine
* A new enzymatic function in the melanogenic pathway. The 5,6-dihydroxyindole-2-carboxylic acid oxidase activity of tyrosinase-related protein-1 (TRP1)
* Polymerization of 5,6-dihydroxyindole-2-carboxylic acid to melanin by the pmel 17/silver locus protein

### Melanosome biogenesis

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* Darkness descends with two Rabs

### Tanning

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* Regulation of constitutive and UVR-induced skin pigmentation by melanocortin 1 receptor isoforms

## Melanosomes passed to keratinocytes

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Laboratory mice provide a useful experimental system for investigation of the cellular mechanisms of mammalian skin pigmentation.

* Mouse coat color mutations: from fancy mice to functional genomics

Working with mice, the transcription factor Foxn1 and the growth factor FGF2 were found to be involved in the melanocyte-keratinocyte interactions that allow melanosomes to be distributed in the skin[1]. Foxn1 was originally studied because of its importance in the development of the thymus as revealed by Foxn1 mutant nude mice. Foxn1 mutations also cause failure of human hair growth[2].

Figure 2. Diagram illustrating melanosome production in melanocytes and the subsequent distribution of melanosomes within keratinocytes. This image is from What Controls Variation in Human Skin Color? by Gregory S. Barsh.

* The quest for the mechanism of melanin transfer
* Tunneling nanotubes: a new route for the exchange of components between animal cells

## See also

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* Alcohols
* Fruit and its importance
* Gene project
* Glandular system
* Hair colors
* Human skin pigmentation
* Medicine
* Minerals
* Neutraceuticals
* Oils
* Pigmented lesions of the oromucosa
* Plants
* Polyphenols
* Pomology
* Terpenoids
* Vitamins
* Waxes

## References

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1. ↑ "Dedicated epithelial recipient cells determine pigmentation patterns" by L. Weiner, R. Han, B. M. Scicchitano, J. Li, K. Hasegawa, M. Grossi, D. Lee and J. L Brissette in Cell (2007) Volume 130, pages 932-942.Entrez PubMed 17803914
2. ↑ "Exposing the human nude phenotype" by J. Frank, C. Pignata, A.A. Panteleyev, D. M. Prowse, H. Baden, L. Weiner, L. Gaetaniello, W. Ahmad, N. Pozzi, P. B. Cserhalmi-Friedman, V. M. Aita, H. Uyttendaele, D. Gordon, J. Ott, J. L. Brissette and A. M. Christiano in Nature (1999) Volume 398, pages 473-474. Entrez PubMed 15316080

## External links

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* "Your Family May Once Have Been A Different Color" by Robert Krulwich. Morning Edition, February 2, 2009.