Correction: Immunogenic Salivary Proteins of Triatoma infestans: Development of a Recombinant Antigen for the Detection of Low-Level Infestation of Triatomines.

[This corrects the article DOI: 10.1371/journal.pntd.

Proteomic Characterization of Synaptosomes from Human Substantia Nigra Indicates Altered Mitochondrial Translation in Parkinson's Disease.

The pathological hallmark of Parkinson's disease (PD) is the loss of neuromelanin-containing dopaminergic neurons within the substantia nigra pars compacta (SNpc). Additionally, numerous studies indicate an altered synaptic function during disease progression. To gain new insights into the molecular processes underlying the alteration of synaptic function in PD, a proteomic study was performed.

One gene, two proteins: coordinated production of a copper chaperone by differential transcript formation and translational frameshifting in Escherichia coli.

Programmed ribosomal frameshifting (PRF) is a translational anomaly causing the ribosome to shift into an alternative reading frame. PRFs are common in viral genomes, using a single nucleotide sequence to code for two proteins in overlapping frames. In bacteria and eukaryota, PRFs are less frequent.

Validation of molecularly imprinted polymers for side chain selective phosphopeptide enrichment.

Selective enrichment techniques are essential for mapping of protein posttranslational modifications (PTMs). Phosphorylation is one of the PTMs which continues to be associated with significant analytical challenges. Particularly problematic are tyrosine-phosphorylated peptides (pY-peptides) resulting from tryptic digestion which commonly escape current chemo- or immuno- affinity enrichments and hence remain undetected.

Mitochondrial defects and neurodegeneration in mice overexpressing wild-type or G399S mutant HtrA2.

The protease HtrA2 has a protective role inside mitochondria, but promotes apoptosis under stress. We previously identified the G399S HtrA2 mutation in Parkinson's disease (PD) patients and reported mitochondrial dysfunction in vitro. Mitochondrial dysfunction is a common feature of PD and related to neurodegeneration.

Low-bias phosphopeptide enrichment from scarce samples using plastic antibodies.

Phosphospecific enrichment techniques and mass spectrometry (MS) are essential tools for comprehending the cellular phosphoproteome. Here, we report a fast and simple approach for low sequence-bias phosphoserine (pS) peptide capture and enrichment that is compatible with low biological or clinical sample input. The approach exploits molecularly imprinted polymers (MIPs, "plastic antibodies") featuring tight neutral binding sites for pS or pY that are capable of cross-reacting with phosphopeptides of protein proteolytic digests.

Proteomics in neurodegenerative diseases: Methods for obtaining a closer look at the neuronal proteome.

The analysis of brain function in normal aging and neurodegenerative, psychiatric, and neurological diseases has long been a subject of interest and has historically been investigated through descriptive analysis of macroscopic or microscopic observations. It is now possible to characterize brain cells, such as neurons and glial cells, or even their subcellular components, at the molecular level. This ability enables researchers to more closely examine brain cell specific molecular pathways to elucidate distinct brain functions.

Effects of zinc on particulate methane monooxygenase activity and structure.

Particulate methane monooxygenase (pMMO) is a membrane-bound metalloenzyme that oxidizes methane to methanol in methanotrophic bacteria. Zinc is a known inhibitor of pMMO, but the details of zinc binding and the mechanism of inhibition are not understood. Metal binding and activity assays on membrane-bound pMMO from Methylococcus capsulatus (Bath) reveal that zinc inhibits pMMO at two sites that are distinct from the copper active site.

Overexpression of the calpain-specific inhibitor calpastatin reduces human alpha-Synuclein processing, aggregation and synaptic impairment in [A30P]αSyn transgenic mice.

Lewy bodies, a pathological hallmark of Parkinson's disease (PD), contain aggregated alpha-synuclein (αSyn), which is found in several modified forms and can be discovered phosphorylated, ubiquitinated and truncated. Aggregation-prone truncated species of αSyn caused by aberrant cleavage of this fibrillogenic protein are hypothesized to participate in its sequestration into inclusions subsequently leading to synaptic dysfunction and neuronal death. Here, we investigated the role of calpain cleavage of αSyn in vivo by generating two opposing mouse models.

Amyloid beta a4 precursor protein-binding family B member 1 (FE65) interactomics revealed synaptic vesicle glycoprotein 2A (SV2A) and sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) as new binding proteins in the human brain.

FE65 is a cytosolic adapter protein and an important binding partner of amyloid precursor protein. Dependent on Thr668 phosphorylation in amyloid precursor protein, which influences amyloidogenic amyloid precursor protein processing, FE65 undergoes nuclear translocation, thereby transmitting a signal from the cell membrane to the nucleus. As this translocation may be relevant in Alzheimer disease, and as FE65 consists of three protein-protein interaction domains able to bind and affect a variety of other proteins and downstream signaling pathways, the identification of the FE65 interactome is of central interest in Alzheimer disease research.

Differential changes in titin domain phosphorylation increase myofilament stiffness in failing human hearts.

Aims: Titin-based myofilament stiffness is defined by the expression levels of the cardiac titin-isoforms, N2B and N2BA, and by phosphorylation of the elastic titin domains N2-B unique sequence (N2-Bus) and PEVK. Phosphorylation of the N2-Bus by cGMP-dependent protein kinase (PKG) or cAMP-dependent protein kinase (PKA) decreases titin stiffness, whereas phosphorylation of the PEVK-domain by PKC increases it. We aimed to identify specific sites within the N2-Bus phosphorylated by PKA and PKG and to determine whether differential changes in titin domain phosphorylation could affect passive stiffness in human failing hearts.

Oxidative stress-induced posttranslational modifications of alpha-synuclein: specific modification of alpha-synuclein by 4-hydroxy-2-nonenal increases dopaminergic toxicity.

Aggregation and neurotoxicity of misfolded alpha-synuclein (αSyn) are crucial mechanisms for progressive dopaminergic neurodegeneration associated with Parkinson's disease (PD). Posttranslational modifications (PTMs) of αSyn caused by oxidative stress, including modification by 4-hydroxy-2-nonenal (HNE-αSyn), nitration (n-αSyn), and oxidation (o-αSyn), have been implicated to promote oligomerization of αSyn. However, it is yet unclear if these PTMs lead to different types of oligomeric intermediates.

Discovering the phosphoproteome of the hydrophobic cytochrome c oxidase membrane protein complex.

Many cellular processes are regulated by reversible phosphorylation to change the activity state of proteins. One example is cytochrome c oxidase (COX) with its important function for energy metabolism in the mitochondria. The phosphorylation of this enzyme is a prerequisite for the allosteric ATP-inhibition and therefore necessary to adapt energy production to ATP demand of the cell.

Multiple phosphorylations of cytochrome c oxidase and their functions.

Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial electron transport chain, is regulated by isozyme expression, allosteric effectors such as the ATP/ADP ratio, and reversible phosphorylation. Of particular interest is the "allosteric ATP-inhibition," which has been hypothesized to keep the mitochondrial membrane potential at low healthy values (<140 mV), thus preventing the formation of superoxide radical anions, which have been implicated in multiple degenerative diseases. It has been proposed that the "allosteric ATP-inhibition" is switched on by the protein kinase A-dependent phosphorylation of COX.

Intestinal aspartate proteases TiCatD and TiCatD2 of the haematophagous bug Triatoma infestans (Reduviidae): sequence characterisation, expression pattern and characterisation of proteolytic activity.

Two aspartate protease encoding complementary deoxyribonucleic acids (cDNA) were characterised from the small intestine (posterior midgut) of Triatoma infestans and the corresponding genes were named TiCatD and TiCatD2. The deduced 390 and 393 amino acid sequences of both enzymes contain two regions characteristic for cathepsin D proteases and the conserved catalytic aspartate residues forming the catalytic dyad, but only TiCatD2 possesses an entire C-terminal proline loop. The amino acid sequences of TiCatD and TiCatD2 show 51-58% similarity to other insect cathepsin D-like proteases and, respectively, 88 and 58% similarity to the aspartate protease ASP25 from T.

Sense and nonsense of pathway analysis software in proteomics.

New developments in proteomics enable scientists to examine hundreds to thousands of proteins in parallel. Quantitative proteomics allows the comparison of different proteomes of cells, tissues, or body fluids with each other. Analyzing and especially organizing these data sets is often a Herculean task.

Regulation of mitochondrial respiration and apoptosis through cell signaling: cytochrome c oxidase and cytochrome c in ischemia/reperfusion injury and inflammation.

Cytochrome c (Cytc) and cytochrome c oxidase (COX) catalyze the terminal reaction of the mitochondrial electron transport chain (ETC), the reduction of oxygen to water. This irreversible step is highly regulated, as indicated by the presence of tissue-specific and developmentally expressed isoforms, allosteric regulation, and reversible phosphorylations, which are found in both Cytc and COX. The crucial role of the ETC in health and disease is obvious since it, together with ATP synthase, provides the vast majority of cellular energy, which drives all cellular processes.

Ultratrace enrichment of tyrosine phosphorylated peptides on an imprinted polymer.

Novel molecularly imprinted polymers (MIPs) designed to bind the side chain of phosphotyrosine can be used as artificial receptors for affinity-based enrichment of proteolytic peptides. In comparison with general enrichment methods for phosphorylated peptides such as TiO(2)-based methods, the pTyr-imprinted polymers offered high selectivity for pTyr-containing peptides down to the low fmol level. This suggests MIPs as a new tool for affinity-based proteomics.

Immunogenic salivary proteins of Triatoma infestans: development of a recombinant antigen for the detection of low-level infestation of triatomines.

Background: Triatomines are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease in Latin America. The most effective vector, Triatoma infestans, has been controlled successfully in much of Latin America using insecticide spraying. Though rarely undertaken, surveillance programs are necessary in order to identify new infestations and estimate the intensity of triatomine bug infestations in domestic and peridomestic habitats.

Phosphorylation and kinetics of mammalian cytochrome c oxidase.

The influence of protein phosphorylation on the kinetics of cytochrome c oxidase was investigated by applying Western blotting, mass spectrometry, and kinetic measurements with an oxygen electrode. The isolated enzyme from bovine heart exhibited serine, threonine, and/or tyrosine phosphorylation in various subunits, except subunit I, by using phosphoamino acid-specific antibodies. The kinetics revealed slight inhibition of oxygen uptake in the presence of ATP, as compared with the presence of ADP.

2-D differential membrane proteome analysis of scarce protein samples.

Proteome studies with small sample amounts are difficult to perform, especially when membrane proteins are the focus of interest. In our study a new method for the analysis of scarce membrane protein samples combining large gel 2-D-CTAB/SDS-PAGE with fluorescence dye saturation labelling (satDIGE) was developed, allowing a highly sensitive differential analysis of different cell states. After Triton X-114 phase partitioning, enriched membrane protein samples of T cells were labelled at cysteine residues using fluorescence dyes and separated by large gel 2D-CTAB/SDS-PAGE.