Protein translocation across membranes

Dalbey, R., Kuhn, A., and von Heijne, G. (1995). Directionality in protein translocation across membranes the N-tail phenomenon. Trends Cell Biol. 5, 380-383. 

Ito, K. (1996). The major pathways of protein translocation across membranes. Genes Cells 1, 337-346. 

Sato S, Ward CL, Kopito RR (1998) Cotranslational ubiquitination of cystic fibrosis transmembrane conductance regiilator in vitro. J Biol Chem 273 7189-7192 Schatz G, Dobberstein B (1996) Common principles of protein translocation across membranes. Science 271 1519-1526... 

Schatz G, Dobberstein (1996) Common principles of protein translocation across membranes. Science 271 1519-1526... 

Craig, E. A., Kang, P.., and Boorstein, W. (1990). A review of the role of 70 kDa heat shock proteins in protein translocation across membranes. Antonie van Leeuwenhoek 58, 137-146. 

Schnell, D. J., and Hebert, I). X. 2005, Protein tran.s ucuns Multifunctional mediators of protein translocation across membranes, Cell 11 L491 505. 

Schatz, G., and Dobberstein, B., Common Principles of Protein Translocation across Membranes, Science, 271 1519-1526, 1996. 

A system of membrane enclosed cisternae in the cytoplasm. The ER is continuous with the outer membrane of the nuclear envelope. The part of the ER coated with ribosomes is called rough ER, the other part is called smooth-surfaced ER. The rough ER is the first compartment of the secretory pathway. Here, membrane proteins are integrated into and secretory proteins translocated across the ER membrane. Furthermore,... 

Whether or not they are lipoproteins, both periplasmic proteins and outer membrane proteins translocate across the inner membrane thus there should be some cellular mechanisms that sort them. Unlike inner membrane proteins, outer membrane proteins do not have characteristic hydrophobic transmembrane segments as such, most, if not all, of them are thought to be composed of ft strands. Moreover, it has been suggested that such conformation may be the determinant of the integration into the outer membrane in other words, these proteins may be spontaneously integrated into the outer membrane. If this assumption is correct, the outer membrane proteins must fold at the periplasm. Another possibility is that the outer membrane proteins are integrated at certain sites where the inner and outer membranes are contacted. This issue has not been solved, but a recent experiment supports the periplasmic folding (Eppens et al., 1997). 

Kuroiwa, T., Sakaguchi, M., Mihara, K., and Omura, T. (1991). Systematic analysis of stop-transfer sequence for microsomal membrane. Biol. Chem. 266, 9251—9255. Kuroiwa, T., Sakaguchi, M., Omura, T., and Mihara, K. (1996). Reinitiation of protein translocation across the endoplasmic reticulum membrane topogenesis of multispan-ning membrane proteins. J. Biol. Chem. 271, 6243—6248. 

Wickner W, Schekman R (2005) Protein translocation across biological membranes. Science 310 1452-1456... 

Yamamoto H, Esaki M, Kanamori T, Tamura Y, Nishikawa S, Endo T (2002) Tim50 is a subunit of the TIM23 complex that links protein translocation across the outer and inner mitochondrial membranes. Cell 111 519-528... 

Like the mitosome, most organelles in a eukaryotic cell do not possess a genome and translation machinery. Consequently, proteins must be imported to these compartments from the cytosol. Yet the membranes separating these organelles from the cytosol are not freely permeable for large hydrophilic molecules of proteins. As a result, the protein translocation is mediated by membrane transporters in a complex energy-consuming process. The mode of protein translocation across these barriers is typical for each compartment. 

Requirements for Protein Translocation across a Membrane The secreted bacterial protein OmpA has a precursor, ProOmpA, which has the amino-terminal signal sequence required for secretion. If purified ProOmpA is denatured with 8 M urea and the urea is then removed (such as... 

Blobel discovered the mechanism for protein translocation across the endoplasmic reticulum membrane—the signal hypothesis. 

Secretory protein translocation. See Stephenson, K Sec-dependent protein translocation across biological membranes. Evolutionary conservation of an essential protein transport pathway. Mol. Membrane Biol. 22,17-28, 2005. 

Scheele, G. (1983) Methods for the study of protein translocation across the RER membrane using the reticulocyte lysate translation system and canine pancreatic microsomal membranes. Methods Enzymol. 96, 94-111. 

Scheper W, Thaminy S, Kais S, Stagljar I, Romisch K. Coordination of N-glycosylation and protein translocation across the endoplasmic reticnlnm membrane by Sssl protein. J. Biol. Chem. 2003 278 37998-38003. 

Protein translocation across the ER membrane can occur by two pathways. Most secretory proteins are cotranslationally translocated in contrast to post-translational translocation destined for other cellular compartments. Transport... 

It is generally accepted that lumenal Hsp70 proteins bind to preproteins and assist in their translocation across membranes in a process requiring ATP hydrolysis. The mechanism of how Hsp70 exerts its action has been the subject of intense interest (Jensen andjohnson, 1999 Pilon and Schekman, 1999 Herrmann and Neupert, 2000 Matouschek et al.,... 

Rapoport, T. A., K. E. Matlack, K. Plath, B. Misselwitz, and O. Staeck. 1999. Post-translational protein translocation across the membrane of the endoplasmic reticulum. Biol. Chem. 380 1143-1150. 

Non-bilayer-forming lipids are also required for protein translocation across the membrane of E. coli. The only non-bilayer-forming lipid in E. coli mutants lacking PE is CL. Protein translocation into inverted membrane vesicles prepared from PE-lacking cells (now enriched in CL) is reduced with divalent cation-depletion but can be enhanced by inclusion of Mg or Ca [ 1 ]. Protein translocation in the absence of divalent cations was restored by incorporation of non-bilayer PE (18 1 acyl chains) but not by bilayer-prone PE (14 0 acyl chains). These results indicate that lipids with a tendency to form non-bilayer stmctures provide a necessary environment for translocation of proteins across the membrane. 

Peptides Derived from Homeodomain Proteins Can Translocate across a Cell Membrane. Homeodomain proteins are transcription factors that are expressed during development and, in some tissues, throughout adult life. These factors, which act by binding to DNA within the nucleus, must translocate across membranes to function. Recent studies suggest that the ability of peptides derived from the third helix of Drosophila Antennapedia homeobox (Antp-HD) to cross membranes is conferred by domains rich in basic amino acids (Table 8.8). A number of other proteins—such as HIV-1 Tat protein [62], transportan [63], and basic amino acid-rich model proteins [64]—have domains that provide a similar enhanced permeation function. 

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