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Molecular mass as a determinant for nuclear San1‐dependent targeting of misfolded cytosolic proteins to proteasomal degradation
Author(s) -
Amm Ingo,
Wolf Dieter H.
Publication year - 2016
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.12213
Subject(s) - cytosol , ubiquitin , ubiquitin ligase , proteasome , cytoplasm , microbiology and biotechnology , endoplasmic reticulum associated protein degradation , aggresome , nuclear protein , f box protein , chemistry , protein degradation , biochemistry , nucleus , protein folding , biology , enzyme , gene , transcription factor
Most misfolded cytosolic proteins in the cell are eliminated by the ubiquitin–proteasome system. In yeast, polyubiquitination of misfolded cytosolic proteins is triggered mainly by the action of two ubiquitin ligases Ubr1, formerly discovered as recognition component of the N‐end rule pathway, and the nuclear ubiquitin ligase San1. For San1‐mediated targeting to proteasomal degradation, cytosolic proteins have to be imported into the nucleus. Selection of misfolded substrates for import into the nucleus had remained elusive. This study shows that an increasing molecular mass of substrates prevents nuclear San1‐triggered proteasomal degradation but renders them susceptible to cytoplasmic Ubr1‐triggered degradation.