Membrane binding of the bacterial signal recognition particle receptor involves two distinct binding sites.
Journal - The Journal of cell biology (United States )
Cotranslational protein targeting in bacteria is mediated by the signal recognition particle (SRP) and FtsY, the bacterial SRP receptor (SR). FtsY is homologous to the SRalpha subunit of eukaryotes, which is tethered to the membrane via its interaction with the membrane-integral SRbeta subunit. Despite the lack of a membrane-anchoring subunit, 30% of FtsY in Escherichia coli are found stably associated with the cytoplasmic membrane. However, the mechanisms that are involved in this membrane association are only poorly understood. Our data indicate that membrane association of FtsY involves two distinct binding sites and that binding to both sites is stabilized by blocking its GTPase activity. Binding to the first site requires only the NG-domain of FtsY and confers protease protection to FtsY. Importantly, the SecY translocon provides the second binding site, to which FtsY binds to form a carbonate-resistant 400-kD FtsY-SecY translocon complex. This interaction is stabilized by the N-terminal A-domain of FtsY, which probably serves as a transient lipid anchor.
|ISSN : ||0021-9525|
|Mesh Heading : ||Bacterial Proteins Binding Sites Carbonates Endopeptidase K Enzyme Inhibitors Escherichia coli Escherichia coli Proteins Guanylyl Imidodiphosphate Intracellular Membranes Mutation Protein Binding Protein Structure, Tertiary Receptors, Cytoplasmic and Nuclear Receptors, Peptide Recombinant Proteins antagonists & inhibitors genetics pharmacology metabolism metabolism pharmacology antagonists & inhibitors chemistry genetics chemistry metabolism|
|Mesh Heading Relevant : ||metabolism metabolism metabolism metabolism|
FtsY, the bacterial signal-recognition particle receptor, interacts functionally and physically with the SecYEG translocon.
Journal - EMBO reports (England )
Co-translational membrane targeting of proteins by the bacterial signal-recognition particle (SRP) requires the specific interaction of the SRP-ribosome nascent chain complex with FtsY, the bacterial SRP receptor (SR). FtsY is homologous to the SRalpha-subunit of the eukaryotic SR, which is tethered to the endoplasmic-reticulum membrane by its interaction with the integral SRbeta-subunit. In contrast to SRalpha, FtsY is partly membrane associated and partly located in the cytosol. However, the mechanisms by which FtsY associates with the membrane are unclear. No gene encoding an SRbeta homologue has been found in bacterial genomes, and the presence of an FtsY-specific membrane receptor has not been shown so far. We now provide evidence for the direct interaction between FtsY and the SecY translocon. This interaction offers an explanation of how the bacterial SRP cycle is regulated in response to available translocation channels.
|ISSN : ||1469-221X|
|Mesh Heading : ||Bacterial Proteins Cell Membrane Escherichia coli Escherichia coli Proteins Mutation Protein Binding Protein Structure, Tertiary Receptors, Cytoplasmic and Nuclear Signal Recognition Particle genetics metabolism genetics genetics genetics|
|Mesh Heading Relevant : ||metabolism metabolism metabolism metabolism metabolism|