The fate of membrane-bound ribosomes following the termination of protein synthesis.
Published
Journal Article
Contemporary models for protein translocation in the mammalian endoplasmic reticulum (ER) identify the termination of protein synthesis as the signal for ribosome release from the ER membrane. We have utilized morphometric and biochemical methods to assess directly the fate of membrane-bound ribosomes following the termination of protein synthesis. In these studies, tissue culture cells were treated with cycloheximide to inhibit elongation, with pactamycin to inhibit initiation, or with puromycin to induce premature chain termination, and ribosome-membrane interactions were subsequently analyzed. It was found that following the termination of protein synthesis, the majority of ribosomal particles remained membrane-associated. Analysis of the subunit structure of the membrane-bound ribosomal particles remaining after termination was conducted by negative stain electron microscopy and sucrose gradient sedimentation. By both methods of analysis, the termination of protein synthesis on membrane-bound ribosomes was accompanied by the release of small ribosomal subunits from the ER membrane; the majority of the large subunits remained membrane-bound. On the basis of these results, we propose that large ribosomal subunit release from the ER membrane is regulated independently of protein translocation.
Full Text
Duke Authors
Cited Authors
- Seiser, RM; Nicchitta, CV
Published Date
- October 27, 2000
Published In
Volume / Issue
- 275 / 43
Start / End Page
- 33820 - 33827
PubMed ID
- 10931837
Pubmed Central ID
- 10931837
International Standard Serial Number (ISSN)
- 0021-9258
Digital Object Identifier (DOI)
- 10.1074/jbc.M004462200
Language
- eng
Conference Location
- United States