Translocation

To establish an infection, Yersinia pseudotuberculosis utilizes a plasmid-encoded type III secretion machine that permits the translocation of several anti-host factors into the cytosol of target eukaryotic cells. Secreted YopD is essential for this process. Pre-secretory stabilization of YopD is mediated by an interaction with its cognate chaperone, LcrH. YopD possesses LcrH binding domains located in the N-terminus and in a predicted amphipathic domain located near the C-terminus. This latter domain is also critical for Yersinia virulence. ...

10p research12 01-06-2013 48 3   Download

The Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) from Vibrio alginolyticus was inactivated by reactive oxygen species. Highest Na+-NQR activity was observed in anaerobically prepared membranes that exhibited 1 : 1 coupling of NADH oxidation and Q reduction activities (1.6 UÆmg)1). Optical and EPR spectroscopy documented the presence of b-type cytochromes, a [2Fe)2S] cluster and an organic radical signal in anaerobically pre- pared membranes from V. alginolyticus.

6p research12 01-06-2013 46 4   Download

The human replication protein Cdc6p is translocated from its chromatin sites to the cytoplasm during the replication phase (S phase) of the cell cycle. However, the amounts of Cdc6p on chromatin remain high during S phase implying either that displaced Cdc6p can rebind to chromatin, or that Cdc6p is synthesized de novo. We have performed metabolic labeling experiments and determined that [35S]methionine is incorporated into Cdc6p at similar rates during the G1 phase and the S phase of the cell cycle. Newly synthesized Cdc6p associates with chromatin....

7p research12 01-06-2013 40 3   Download

TheatpBandatpF genes ofPropionigenium modestumwere cloned as His-tag fusion constructs and expressed in Escherichia coli.Both recombinant subunits a and b were purified via Ni 2+ chelate affinitychromatography. A func-tionallyactive Focomplex was reassembledin vitro from subunits a, band c, and incorporated into liposomes.

7p research12 29-04-2013 28 3   Download

We have previously demonstrated that the steroid hormone 1a,25(OH)2-vitamin D3 [1a,25(OH)2D3] stimulates the production ofinositol trisphosphate (InsP3), the breakdown product ofphosphatidylinositol 4,5-biphosphate (PtdInsP2) by phospholipase C (PtdIns-PLC), and activates the cyto-solic tyrosine kinase c-Src in skeletal muscle cells. In the present study we examined whether 1a,25(OH)2D3induces the phosphorylation and membrane translocation ofPLCc and the mechanism involved in this isozyme activation. ...

10p research12 29-04-2013 44 4   Download

Membrane-bound transhydrogenases are conformationally driven proton-pumps which couple an inward proton translocation to the reversible reduction of NADP + by NADH(forward reaction). This reaction is stimulatedby an electrochemical protongradient,Dp, presumably throughan increased release of NADPH. The enzymes have three domains: domain II spans the membrane, while domain I and III are hydrophilic and contain the binding sites for NAD(H) andNADP(H), respectively.

11p research12 23-04-2013 35 3   Download

Translocation through the plasma membrane is a major limiting step for the cellular delivery of macromolecules. A promising strategy to overcome this problem consists in the chemical conjugation (or fusion) to cell penetrating peptides (CPP) derived from proteins able to cross the plasma membrane. A large number of di€erent cargo mol-ecules such as oligonucleotides, peptides, peptide nucleic acids, proteins or even nanoparticles have been internalized in cells by this strategy.

8p research12 23-04-2013 31 4   Download

Recent crosslinking studies indicated the localization of the coupling ion binding site in the Na + -translocating F1F0 ATP synthase ofIlyobacter tartaricus within the hydrophobic part of the bilayer.Similarly, a membrane embedded H + -binding site is accepted for the H + -trans-locating F1F0 ATP synthase ofEscherichia coli.For a more definite analysis, we performed parallax analysis of fluorescence quenching with ATP synthases from both I. tartaricus and E. coli.

9p tumor12 22-04-2013 26 2   Download

In the accompanying paper [Adams, H., Scotti, P.A., de Cock, H., Luirink, J. & Tommassen, J. (2002)Eur. J. Bio-chem.269, 5564–5571.], we showed that the precursor of outer-membrane proteinPhoEofEscherichia coliwithaGly to Leu substitution at position )10 in the signal sequence (G-10L) is targeted to the SecYEGtranslocon via the signal-recognition particle (SRP) route, instead of via the SecB pathway. Here, we studied the fate of the mutant precursor in aprlA4mutant strain.

9p tumor12 22-04-2013 39 3   Download

Signal sequences often containa-helix-destabilizing amino acids within the hydrophobic core. In the precursor of the Escherichia coliouter-membrane protein PhoE,the glycine residue at position)10 (Gly )10 ) is thought to be responsible for the break in the a-helix. Previously,we showed that substitution of Gly )10 bya-helix-promoting residues (Ala, Cys or Leu) reduced the proton-motive force dependency of the translocation of the precursor,but the actual role of the helix breaker remained obscure. ...

8p tumor12 22-04-2013 34 3   Download

Previous results have shown that theoncoembryonicmarker a-fetoprotein (AFP) is able to induce apoptosis in tumor cells through activation of caspase 3, bypassing Fas-dependent and tumor necrosis factor receptor-dependent signaling. In this study we further investigate the molecular interactions involvedin the AFP-mediatedsignaling of apoptosis. We show that AFP treatment of tumor cells is accompaniedby cytosolic translocation of mitochondrial cytochromec.

12p tumor12 20-04-2013 44 2   Download

Annexin A1 (ANX-1), a calcium-dependent, phospholipid binding protein, is known to be involved in diverse cellular processes, including regulation ofcell growth and differen-tiation, apoptosis, and inflammation. The mitogen phorbol 12-myristate 13-acetate (PMA) induces expression and phosphorylation ofANX-1. However, the roles of ANX-1 in PMA-induced signal transduction is unknown. Here, we study the cellular localization ofANX-1 in the PMA-induced signal transduction process.

6p tumor12 20-04-2013 31 4   Download

The protein-modifying agent arsenite stimulates glucose uptake in 3T3-L1 adipocytes. In the current study we have analysed the signalling pathways that contribute to this response. By subcellular fractionation we observed that arsenite, like insulin, induces translocation of the GLUT1 and GLUT4 glucose transporters from the low-density membrane fraction to the plasma membrane. Arsenite did not activate early steps of the insulin receptor (IR)-signalling pathway and the response was insensitive to inhibition of phosphatidylinositol-3¢-kinase (PI-3¢)kinaseby wortman-nin. ...

13p tumor12 20-04-2013 36 3   Download

Targeting of proteins to and translocation across the membranes is a fundamental biological process in all organisms. In bacteria, the twin arginine translocation (Tat) system can transport folded proteins. Here, we demonstrate in vivo that the high potential iron-sulfur protein (HiPIP) from Allochromatium vinosumis trans-located into the periplasmic space by the Tat system of Escherichia coli. In vitro, reconstituted HiPIP precursor (preHoloHiPIP) was targeted to inverted membrane vesicles from E. ...

11p tumor12 20-04-2013 32 2   Download

High-resolution crystal structures of large ribosomal subunits from Deinococcus radioduranscomplexed with tRNA-mimics indicate that precise substrate positioning, mandatory for efficient protein biosynthesis with no further conformational rearrangements, is governed by remote interactions of the tRNA helical features.

14p fptmusic 16-04-2013 41 3   Download

Most of the examples of protein translocation across a membrane (such as the import of classical secretory proteins into the endoplasmic reticulum, import of proteins into mitochondria and peroxisomes, as well as protein import into and export from the nucleus), are understood in great detail.

11p fptmusic 16-04-2013 39 4   Download

The placental leucine aminopeptidase (P-LAP)/oxytocinase is amembrane-bound enzyme thought to play an important role during pregnancy.In this study, we identified the pres-ence of P-LAP protein in the renal distal tubules and col-lecting ducts.In rat NRK52E cells derived from renal tubules, P-LAP was localized mainly in the intracellular compartment.Upon the treatment of cells with 8-arginine-vasopressin (AVP), a significant increase in the surface level of P-LAP was observed.

7p fptmusic 16-04-2013 24 2   Download

A novel ATP-dependent nuclear DNA unwinding enzyme from pea has been purified to apparent homogeneity and characterized. This enzyme is present at extremely low abundance and has the highest specific activity among plant helicases. It is a heterodimer of 54 and 66 kDa polypeptides as determined by SDS/PAGE. On gel filtration chroma-tography and glycerol gradient centrifugation it gives a native molecular mass of 120 kDa and is named as pea DNA helicase 120 (PDH120).

11p fptmusic 16-04-2013 39 3   Download

KdpD is a sensor kinase protein in the inner membrane of Escherichia colicontaining four transmembrane regions. The periplasmic loops connecting the transmembrane regions are intriguingly short and proteasemapping allowed us to only follow the translocation of the second periplasmic loop. The results show that neither the Sec translocase nor theYidCprotein are required formembrane insertion of the second loop ofKdpD.

11p fptmusic 16-04-2013 32 4   Download

Transmembrane proton translocation in the photosynthetic membranes of the purple bacteriumRhodobacter sphaero-ides is driven by light and performed by two transmem-brane complexes; the photosynthetic reaction center and the ubiquinol–cytochromecoxidoreductase complex, coupled by two mobile electron carriers; the cytochrome and the quinone. This paper focuses on the kinetics and thermo-dynamics of the interaction between the lipophylic electron carrier ubiquinone-10 and the photosynthetic enzyme reconstituted in liposomes. ...

11p fptmusic 12-04-2013 56 2   Download