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A single ubiquitin is sufficient for cargo protein entry into MVBs in the absence of ESCRT ubiquitination
Journal article   Open access   Peer reviewed

A single ubiquitin is sufficient for cargo protein entry into MVBs in the absence of ESCRT ubiquitination

Daniel K. Stringer and Robert C. Piper
The Journal of cell biology, Vol.192(2), pp.229-242
01/24/2011
DOI: 10.1083/jcb.201008121
PMCID: PMC3172180
PMID: 21242292
url
https://doi.org/10.1083/jcb.201008121View
Published (Version of record) Open Access

Abstract

ESCRTs (endosomal sorting complexes required for transport) bind and sequester ubiquitinated membrane proteins and usher them into nnultivesicular bodies (MVBs). As Ubiquitin (Ub)-binding proteins, ESCRTs themselves become ubiquitinated. However, it is unclear whether this regulates a critical aspect of their function or is a nonspecific consequence of their association with the Ub system. We investigated whether ubiquitination of the ESCRTs was required for their ability to sort cargo into the MVB lumen. Although we found that Rsp5 was the main Ub ligase responsible for ubiquitination of ESCRT-0, elimination of Rsp5 or elimination of the ubiquitinatable lysines within ESCRT-0 did not affect MVB sorting. Moreover, by fusing the catalytic domain of deubiquitinating peptidases onto ESCRTs, we could block ESCRT ubiquitination and the sorting of proteins that undergo Rsp5-dependent ubiquitination. Yet, proteins fused to a single Ub moiety were efficiently delivered to the MVB lumen, which strongly indicates that a single Ub is sufficient in sorting MVBs in the absence of ESCRT ubiquitination.
Cell Biology Life Sciences & Biomedicine Science & Technology

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