[Untitled]
In: Molecular Biology Reports, Jg. 26 (1999), S. 125-130
Online
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Zugriff:
Degradation of misfolded or unassembled proteins of the secretory pathway is an essential function of the quality control system of the Endoplasmic Reticulum (ER). Using yeast as a model organism we show that a mutated and therefore misfolded soluble lumenal protein carboxypeptidase yscY (CPY*), and a polytopic membrane protein, the ATP-binding cassette transporter Pdr5 (Pdr5*), are retrograde transported out of the ER and degraded via the cytoplasmic ubiquitin-proteasome system. Retrograde transport depends on an intact Sec61 translocon. Complete import of CPY* into the lumen of the ER requests a new targeting mechanism for retrograde transport of the malfolded enzyme through the Sec61 channel to occur. For soluble CPY*, but not for the polytopic membrane protein Pdr5* action of the ER-lumenal Hsp70 chaperone Kar2 is necessary to deliver the protein to the ubiquitin-proteasome machinery. Polyubiquitination of CPY* and Pdr5* by the ubiquitin conjugating enzymes Ubc6 and Ubc7 is crucial for degradation to occur. Also transport of CPY* out of the ER-lumen depends on ubiquitination. Newly discovered proteins of the ER membrane, Der1, Der3/Hrd1, and Hrd3 are specifically involved in the retrograde transport processes.
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Autor/in / Beteiligte Person: | Plemper, Richard K. ; Wolf, Dieter H. |
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Zeitschrift: | Molecular Biology Reports, Jg. 26 (1999), S. 125-130 |
Veröffentlichung: | Springer Science and Business Media LLC, 1999 |
Medientyp: | unknown |
ISSN: | 0301-4851 (print) |
DOI: | 10.1023/a:1006913215484 |
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