Down-Regulation of the Trypanosomatid Signal Recognition Particle Affects the Biogenesis of Polytopic Membrane Proteins but Not of Signal Peptide-Containing Proteins
| Autor: | Malcolm J. McConville, Dennis M. Dwyer, Avigail Erlanger, Hanoch Goldshmidt, Vered Ozeri, James E Vince, Shulamit Michaeli, Yaron Vagima, Yaniv Lustig, Scott M. Landfear |
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| Rok vydání: | 2007 |
| Předmět: |
Signal peptide
Recombinant Fusion Proteins Trypanosoma brucei brucei Protozoan Proteins Down-Regulation Protein Sorting Signals Biology environment and public health Microbiology Cell Line RNA Small Cytoplasmic Animals Signal recognition particle RNA Molecular Biology Signal recognition particle receptor Genes Dominant Signal recognition particle Endoplasmic reticulum membrane Membrane Proteins RNA Articles General Medicine Transport protein Cell biology Protein Transport Biochemistry Membrane protein Mutation Trypanosomatina RNA Interference Signal Recognition Particle |
| Zdroj: | Eukaryotic Cell. 6:1865-1875 |
| ISSN: | 1535-9786 1535-9778 |
| Popis: | Protein translocation across the endoplasmic reticulum is mediated by the signal recognition particle (SRP). In this study, the SRP pathway in trypanosomatids was down-regulated by two approaches: RNA interference (RNAi) silencing of genes encoding SRP proteins in Trypanosoma brucei and overexpression of dominant-negative mutants of 7SL RNA in Leptomonas collosoma . The biogenesis of both signal peptide-containing proteins and polytopic membrane proteins was examined using endogenous and green fluorescent protein-fused proteins. RNAi silencing of SRP54 or SRP68 in T. brucei resulted in reduced levels of polytopic membrane proteins, but no effect on the level of signal peptide-containing proteins was observed. When SRP deficiency was achieved in L. collosoma by overexpression of dominant-negative mutated 7SL RNA, a major effect was observed on polytopic membrane proteins but not on signal peptide-containing proteins. This study included two trypanosomatid species, tested various protein substrates, and induced depletion of the SRP pathway by affecting either the levels of SRP binding proteins or that of SRP RNA. Our results demonstrate that, as in bacteria but in contrast to mammalian cells, the trypanosome SRP is mostly essential for the biogenesis of membrane proteins. |
| Databáze: | OpenAIRE |
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