GSBS Student Publications

Title

Role of Sec61alpha in the regulated transfer of the ribosome-nascent chain complex from the signal recognition particle to the translocation channel

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Biology

Date

2-17-2000

Document Type

Article

Medical Subject Headings

Animals; Biological Transport; Dogs; Endoplasmic Reticulum, Rough; Guanosine Triphosphate; Hydrolysis; Membrane Glycoproteins; Membrane Proteins; Microsomes; Models, Biological; *Protein Biosynthesis; Protein Sorting Signals; Receptors, Cytoplasmic and Nuclear; Receptors, Peptide; Ribosomes; *Saccharomyces cerevisiae Proteins; Signal Recognition Particle

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Targeting of ribosome-nascent chain complexes to the translocon in the endoplasmic reticulum is mediated by the concerted action of the signal recognition particle (SRP) and the SRP receptor (SR). Ribosome-stripped microsomes were digested with proteases to sever cytoplasmic domains of SRalpha, SRbeta, TRAM, and the Sec61 complex. We characterized protein translocation intermediates that accumulate when Sec61alpha or SRbeta is inactivated by proteolysis. In the absence of a functional Sec61 complex, dissociation of SRP54 from the signal sequence is blocked. Experiments using SR proteoliposomes confirmed the assembly of a membrane-bound posttargeting intermediate. These results strongly suggest that the Sec61 complex regulates the GTP hydrolysis cycle of the SRP-SR complex at the stage of signal sequence dissociation from SRP54.

Rights and Permissions

Citation: Cell. 2000 Feb 4;100(3):333-43.

Related Resources

Link to Article in PubMed

Journal Title

Cell

PubMed ID

10676815