| Autor: |
Marshall RS; Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom., Jolliffe NA, Ceriotti A, Snowden CJ, Lord JM, Frigerio L, Roberts LM |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of biological chemistry [J Biol Chem] 2008 Jun 06; Vol. 283 (23), pp. 15869-77. Date of Electronic Publication: 2008 Apr 17. |
| DOI: |
10.1074/jbc.M709316200 |
| Abstrakt: |
When the catalytic A subunits of the castor bean toxins ricin and Ricinus communis agglutinin (denoted as RTA and RCA A, respectively) are delivered into the endoplasmic reticulum (ER) of tobacco protoplasts, they become substrates for ER-associated protein degradation (ERAD). As such, these orphan polypeptides are retro-translocated to the cytosol, where a significant proportion of each protein is degraded by proteasomes. Here we begin to characterize the ERAD pathway in plant cells, showing that retro-translocation of these lysine-deficient glycoproteins requires the ATPase activity of cytosolic CDC48. Lysine polyubiquitination is not obligatory for this step. We also show that although RCA A is found in a mannose-untrimmed form prior to its retro-translocation, a significant proportion of newly synthesized RTA cycles via the Golgi and becomes modified by downstream glycosylation enzymes. Despite these differences, both proteins are similarly retro-translocated. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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