The tetraspanin CD63 regulates ESCRT-independent and -dependent endosomal sorting during melanogenesis

Dev Cell. 2011 Oct 18;21(4):708-21. doi: 10.1016/j.devcel.2011.08.019. Epub 2011 Sep 29.


Cargo sorting to intraluminal vesicles (ILVs) of multivesicular endosomes is required for lysosome-related organelle (LRO) biogenesis. PMEL-a component of melanocyte LROs (melanosomes)-is sorted to ILVs in an ESCRT-independent manner, where it is proteolytically processed and assembled into functional amyloid fibrils during melanosome maturation. Here we show that the tetraspanin CD63 directly participates in ESCRT-independent sorting of the PMEL luminal domain, but not of traditional ESCRT-dependent cargoes, to ILVs. Inactivating CD63 in cell culture or in mice impairs amyloidogenesis and downstream melanosome morphogenesis. Whereas CD63 is required for normal PMEL luminal domain sorting, the disposal of the remaining PMEL transmembrane fragment requires functional ESCRTs but not CD63. In the absence of CD63, the PMEL luminal domain follows this fragment and is targeted for ESCRT-dependent degradation. Our data thus reveal a tight interplay regulated by CD63 between two distinct endosomal ILV sorting processes for a single cargo during LRO biogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid / metabolism*
  • Animals
  • Cells, Cultured
  • Endosomal Sorting Complexes Required for Transport*
  • Endosomes / physiology*
  • Fluorescent Antibody Technique
  • HeLa Cells
  • Humans
  • Image Processing, Computer-Assisted
  • Lysosomes / metabolism
  • Melanocytes / cytology*
  • Melanocytes / metabolism
  • Melanosomes / metabolism*
  • Mice
  • Mice, Knockout
  • Multivesicular Bodies
  • Organelles / metabolism
  • Protein Transport
  • Tetraspanin 30 / physiology*


  • Amyloid
  • Cd63 protein, mouse
  • Endosomal Sorting Complexes Required for Transport
  • Tetraspanin 30