The 26S proteasome is a multisubunit complex that selectively degrades ubiquitin conjugated proteins. Two studies (this Article and the Letter Dikic doi:10.1038/nature06924) show that a known component of the proteasome, Rpn13, functions as a novel ubiquitin binding receptor, and structural studies reveal a novel mode of ubiquitin recognition. Rpn13 is also a receptor for a deubiquitinating enzyme, suggesting a linkage between ubiquitin chain recognition and disassembly.
- Koraljka Husnjak
- Suzanne Elsasser
- Ivan Dikic