A complex of the signal sequence binding protein and the SRP RNA promotes translocation of nascent proteins

Hauser, Stefanie and Bacher, Gerald and Dobberstein, Bernhard and Lütcke, Henrich

The EMBO Journal, 14 (22). pp. 5485-5493.

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Abstract

Translocation of proteins across the endoplasmic reticulum membrane is initiated by the signal recognition particle (SRP), a cytoplasmic ribonucleoprotein complex consisting of a 7S RNA and six polypeptides. To investigate the functions of the SRP components, we have tested the activities of several SRP subparticles. We show that the SRP GTPase (SRP54) alone binds a signal sequence and discriminates it from a non-signal sequence. Although SRP54 alone is unable to promote translocation, SRP54 in a complex with SRP RNA is both necessary and sufficient to promote translocation of an elongation-arrested nascent protein in a GTPregulated manner. For co-translational translocation, additional SRP components are required. We discuss the implications of our results for the function of the Escherichia coli SRP which is homologous to the SRP54/SRP-RNA complex.

Item Type:	Article
Journal or Publication Title:	The EMBO Journal
Volume:	14
Number:	22
Date:	1995
Page Range:	pp. 5485-5493
Faculties / Institutes:	Service facilities > Center for Molecular Biology Heidelberg
Subjects:	570 Life sciences
Uncontrolled Keywords:	endoplasmic reticulum , protein translocation , signal recognition particle (SRP) , signal sequence recognition , 4.5S RNA
Schriftenreihe ID:	Works by Bernhard Dobberstein