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Elongation arrest is a physiologically important function of signal recognition particle
Author(s) -
Mason Nicola,
Ciufo Leonora F.,
Brown Jeremy D.
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.15.4164
Subject(s) - biology , elongation , function (biology) , signal recognition particle , signal (programming language) , microbiology and biotechnology , biophysics , computational biology , biochemistry , peptide sequence , signal peptide , gene , computer science , materials science , ultimate tensile strength , metallurgy , programming language
Signal recognition particle (SRP) targets proteins for co‐translational insertion through or into the endoplasmic reticulum membrane. Mammalian SRP slows nascent chain elongation by the ribosome during targeting in vitro . This ‘elongation arrest’ activity requires the SRP9/14 subunit of the particle and interactions of the C‐terminus of SRP14. We have purified SRP from Saccharomyces cerevisiae and demonstrated that it too has elongation arrest activity. A yeast SRP containing Srp14p truncated at its C‐terminus (ΔC29) did not maintain elongation arrest, was substantially deficient in promoting translocation and interfered with targeting by wild‐type SRP. In vivo , this mutation conferred a constitutive defect in the coupling of protein translation and translocation and temperature‐sensitive growth, but only a slight defect in protein translocation. In combination, these data indicate that the primary defect in SRP ΔC29 is in elongation arrest, and that this is a physiologically important and conserved function of eukaryotic SRP.