First published online July 12, 2005
Journal of Cell Science 118, 1405e (2005)
© The Company of Biologists Limited
...endosomes out of sorts
During endocytosis, cargo receptors are sorted in early endosomes according to whether they are destined for recycling or degradation. However, it is unclear whether cargos move through predetermined structures or whether cargo selection underpins endosomal morphology. Phillip Woodman and colleagues now provide evidence for the latter scenario by examining endosomes after inhibiting the sorting of epidermal growth factor receptor (EGFR) by depleting cells of tumour susceptibility gene 101 (TSG101; see p. 3003). TSG101, a ubiquitin-binding protein required for EGFR sorting, is the mammalian orthologue of a subunit of the yeast ESCRT-1 complex, which mediates ubiquitin-dependent sorting in early endosomes as they mature into multivesicular bodies. The authors show that knocking down TSG101 yields multicisternal early endosomes that have multiple sorting defects and closely resemble the defective endosomes seen in yeast mutants lacking functional ESCRT-1. Thus, they suggest, if ESCRT-1 complexes cannot form, ubiquitylated cargos are not recruited to the appropriate regions of early endosomes and, consequently, the membrane reorganisations needed to form normal endosomal vacuoles and tubules go awry.
Related articles in JCS:
- Depletion of TSG101 forms a mammalian `Class E' compartment: a multicisternal early endosome with multiple sorting defects
- Aurelie Doyotte, Matthew R. G. Russell, Colin R. Hopkins, and Philip G. Woodman
JCS 2005 118: 3003-3017.
[Abstract]
[Full Text]
