Secretion of LamB-LacZ by the Signal Recognition Particle Pathway of Escherichia coli
AUTOR(ES)
Bowers, Christina Wilson
FONTE
American Society for Microbiology
RESUMO
LamB-LacZ fusion proteins have classically been used in studies of the general secretion pathway of Escherichia coli. Here we describe how increasing signal sequence hydrophobicity routes LamB-LacZ Hyb42-1 to the signal recognition particle (SRP) pathway. Secretion of this hydrophobic fusion variant (H*LamB-LacZ) was reduced in the absence of fully functional Ffh and Ffs, and the translocator jamming caused by Hyb42-1 was prevented by efficient delivery of the fusion to the periplasm. Finally, we found that in the absence of the ribosome-associated chaperone, trigger factor (Tig), LamB-LacZ localized to the periplasm in a SecA-dependent, SRP-independent fashion. Collectively, our results provide compelling in vivo evidence that there is an SRP-dependent cotranslational targeting mechanism in E. coli and argue against a role for trigger factor in pathway discrimination.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=193965Documentos Relacionados
- Physiological Basis for Conservation of the Signal Recognition Particle Targeting Pathway in Escherichia coli
- Differential use of the signal recognition particle translocase targeting pathway for inner membrane protein assembly in Escherichia coli
- Genetic Screen Yields Mutations in Genes Encoding All Known Components of the Escherichia coli Signal Recognition Particle Pathway
- Association of Escherichia coli ribosomes with the inner membrane requires the signal recognition particle receptor but is independent of the signal recognition particle
- The DsbA Signal Sequence Directs Efficient, Cotranslational Export of Passenger Proteins to the Escherichia coli Periplasm via the Signal Recognition Particle Pathway