Rab11b mediates melanin transfer between donor melanocytes and acceptor keratinocytes via coupled exo/endocytosis

Abul K. Tarafder, Giulia Bolasco, Maria S. Correia, Francisco J C Pereira, Lucio Iannone, Alistair N. Hume, Niall Kirkpatrick, Mauro Picardo, Maria R. Torrisi, Inês P. Rodrigues, José S. Ramalho, Clare E. Futter, Duarte C. Barral, Miguel C. Seabra

Research output: Contribution to journalArticle

Abstract

The transfer of melanin from melanocytes to keratinocytes is a crucial process underlying maintenance of skin pigmentation and photoprotection against UV damage. Here, we present evidence supporting coupled exocytosis of the melanin core, or melanocore, by melanocytes and subsequent endocytosis by keratinocytes as a predominant mechanism of melanin transfer. Electron microscopy analysis of human skin samples revealed three lines of evidence supporting this: (1) the presence of melanocores in the extracellular space; (2) within keratinocytes, melanin was surrounded by a single membrane; and (3) this membrane lacked the melanosomal membrane protein tyrosinase-related protein 1 (TYRP1). Moreover, co-culture of melanocytes and keratinocytes suggests that melanin exocytosis is specifically induced by keratinocytes. Furthermore, depletion of Rab11b, but not Rab27a, caused a marked decrease in both keratinocyte-stimulated melanin exocytosis and transfer to keratinocytes. Thus, we propose that the predominant mechanism of melanin transfer is keratinocyte-induced exocytosis, mediated by Rab11b through remodeling of the melanosome membrane, followed by subsequent endocytosis by keratinocytes.

Original languageEnglish
Pages (from-to)1056-1066
Number of pages11
JournalJournal of Investigative Dermatology
Volume134
Issue number4
DOIs
Publication statusPublished - 2014

ASJC Scopus subject areas

  • Dermatology
  • Biochemistry
  • Cell Biology
  • Molecular Biology

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  • Cite this

    Tarafder, A. K., Bolasco, G., Correia, M. S., Pereira, F. J. C., Iannone, L., Hume, A. N., Kirkpatrick, N., Picardo, M., Torrisi, M. R., Rodrigues, I. P., Ramalho, J. S., Futter, C. E., Barral, D. C., & Seabra, M. C. (2014). Rab11b mediates melanin transfer between donor melanocytes and acceptor keratinocytes via coupled exo/endocytosis. Journal of Investigative Dermatology, 134(4), 1056-1066. https://doi.org/10.1038/jid.2013.432