Delivery of internalized ricin from endosomes to cisternal golgi elements is a discontinuous, temperature-sensitive process
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
Galactose-terminating membrane glycoproteins and glycolipids on two established human breast carcinoma cell lines were tagged at 4 °C with a ricin-horseradish peroxidase conjugate (Ri-HRP). The cells were then incubated for various periods of time at 37 or 18 °C. After fixation and diaminobenzidine cytochemistry, the compartments reached by Ri-HRP were studied by analyzing thin serial sections. In both cell types a highly pleomorphic endosomal system comprising vacuolar elements as well as smaller, sometimes branched, tubular elements (tubular endosomes) was revealed at both 37 and 18 °C. At 37 °C Ri-HRP was consistently observed in flattened cisterns of the Golgi region in 30-40% of the Golgi complexes examined after 30-60 min of incubation. However, no Ri-HRP reached such Golgi elements at 18 °C, even after incubation for 180 min. Moreover, at 18 °C the ability of ricin to inhibit protein synthesis was virtually abolished, whereas the effect of diphtheria toxin was reduced much less. Following incubation with a monovalent transferrin-HRP conjugate or with unconjugated HRP, no labeling of cisternal Golgi elements was detected. These data indicate that delivery of galactose-terminating membrane molecules from endosomes to the Golgi complex is a discontinuous, temperature-sensitive process and that this process may be required for optimal ricin A-chain translocation.
Originalsprog | Engelsk |
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Tidsskrift | Experimental Cell Research |
Vol/bind | 171 |
Udgave nummer | 1 |
Sider (fra-til) | 137-152 |
Antal sider | 16 |
ISSN | 0014-4827 |
DOI | |
Status | Udgivet - jul. 1987 |
ID: 347535818