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