%0 Journal Article
%A Hauser, Stefanie
%A Bacher, Gerald
%A Dobberstein, Bernhard
%A Lütcke, Henrich
%D 1995
%F heidok:8478
%J The EMBO Journal
%K endoplasmic reticulum , protein translocation , signal recognition particle (SRP) , signal sequence recognition , 4.5S RNA
%N 22
%P 5485-5493
%R 10.11588/heidok.00008478
%T A complex of the signal sequence binding protein and the SRP RNA promotes translocation of nascent proteins
%U https://archiv.ub.uni-heidelberg.de/volltextserver/8478/
%V 14
%X 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.