scholarly journals The human proteome co-regulation map reveals functional relationships between proteins

2019 ◽  
Author(s):  
Georg Kustatscher ◽  
Piotr Grabowski ◽  
Tina A. Schrader ◽  
Josiah B. Passmore ◽  
Michael Schrader ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Function ◽  
Cell Biology ◽  
Mammalian Cells ◽  
Data Matrix ◽  
Peroxisomal Membrane ◽  
Isotope Labelling ◽  
Functional Relationships ◽  
Human Proteins ◽  
Functional Context

The annotation of protein function is a longstanding challenge of cell biology that suffers from the sheer magnitude of the task. Here we present ProteomeHD, which documents the response of 10,323 human proteins to 294 biological perturbations, measured by isotope-labelling mass spectrometry. Using this data matrix and robust machine learning we create a co-regulation map of the cell that reflects functional associations between human proteins. The map identifies a functional context for many uncharacterized proteins, including microproteins that are difficult to study with traditional methods. Co-regulation also captures relationships between proteins which do not physically interact or co-localize. For example, co-regulation of the peroxisomal membrane protein PEX11β with mitochondrial respiration factors led us to discover a novel organelle interface between peroxisomes and mitochondria in mammalian cells. The co-regulation map can be explored atwww.proteomeHD.net.

The challenge of detecting modifications on proteins

2020 ◽  
Vol 64 (1) ◽  
pp. 135-153 ◽  
Author(s):  
Lauren Elizabeth Smith ◽  
Adelina Rogowska-Wrzesinska
Keyword(s):  
Mass Spectrometry ◽  
Protein Function ◽  
Chemical Properties ◽  
Lysine Acetylation ◽  
Mass Determination ◽  
Post Translational Modifications ◽  
Site Specific ◽  
The Common

Abstract Post-translational modifications (PTMs) are integral to the regulation of protein function, characterising their role in this process is vital to understanding how cells work in both healthy and diseased states. Mass spectrometry (MS) facilitates the mass determination and sequencing of peptides, and thereby also the detection of site-specific PTMs. However, numerous challenges in this field continue to persist. The diverse chemical properties, low abundance, labile nature and instability of many PTMs, in combination with the more practical issues of compatibility with MS and bioinformatics challenges, contribute to the arduous nature of their analysis. In this review, we present an overview of the established MS-based approaches for analysing PTMs and the common complications associated with their investigation, including examples of specific challenges focusing on phosphorylation, lysine acetylation and redox modifications.

Resolution of a protein sequence ambiguity by X-ray crystallographic and mass spectrometric methods

1992 ◽  
Vol 25 (2) ◽  
pp. 205-210 ◽  
Author(s):  
L. J. Keefe ◽  
E. E. Lattman ◽  
C. Wolkow ◽  
A. Woods ◽  
M. Chevrier ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Electron Density ◽  
Mass Spectrometric ◽  
Amino Acid Sequences ◽  
Data Matrix ◽  
Protein Crystal ◽  
Insertion Mutant ◽  
Laser Desorption Mass Spectrometry ◽  
X Ray

Ambiguities in amino acid sequences are a potential problem in X-ray crystallographic studies of proteins. Amino acid side chains often cannot be reliably identified from the electron density. Many protein crystal structures that are now being solved are simple variants of a known wild-type structure. Thus, cloning artifacts or other untoward events can readily lead to cases in which the proposed sequence is not correct. An example is presented showing that mass spectrometry provides an excellent tool for analyzing suspected errors. The X-ray crystal structure of an insertion mutant of Staphylococcal nuclease has been solved to 1.67 Å resolution and refined to a crystallographic R value of 0.170 [Keefe & Lattman (1992). In preparation]. A single residue has been inserted in the C-terminal α helix. The inserted amino acid was believed to be an alanine residue, but the final electron density maps strongly indicated that a glycine had been inserted instead. To confirm the observations from the X-ray data, matrix-assisted laser desorption mass spectrometry was employed to verify the glycine insertion. This mass spectrometric technique has sufficient mass accuracy to detect the methyl group that distinguishes glycine from alanine and can be extended to the more common situation in which crystallographic measurements suggest a problem with the sequence, but cannot pinpoint its location or nature.

scholarly journals Avoided motifs: short amino acid strings missing from protein datasets

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Function ◽  
Large Protein ◽  
New Approach ◽  
Cellular Context ◽  
Human Proteins ◽  
Context Specific ◽  
Protein Datasets

Abstract According to the amino acid composition of natural proteins, it could be expected that all possible sequences of three or four amino acids will occur at least once in large protein datasets purely by chance. However, in some species or cellular context, specific short amino acid motifs are missing due to unknown reasons. We describe these as Avoided Motifs, short amino acid combinations missing from biological sequences. Here we identify 209 human and 154 bacterial Avoided Motifs of length four amino acids, and discuss their possible functionality according to their presence in other species. Furthermore, we determine two Avoided Motifs of length three amino acids in human proteins specifically located in the cytoplasm, and two more in secreted proteins. Our results support the hypothesis that the characterization of Avoided Motifs in particular contexts can provide us with information about functional motifs, pointing to a new approach in the use of molecular sequences for the discovery of protein function.

scholarly journals Atlas der SARS-CoV-2-RNA-Protein-Interaktionen in infizierten Zellen

BIOspektrum ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 376-379
Author(s):  
Nora Schmidt ◽  
Mathias Munschauer
Keyword(s):  
Mass Spectrometry ◽  
Viral Rna ◽  
Defense Strategies ◽  
Pharmacological Inhibition ◽  
Novel Therapeutics ◽  
Contact Sites ◽  
Human Proteins ◽  
Infected Cells

AbstractUsing RNA antisense purification and mass spectrometry, we identified more than 100 human proteins that directly and specifically bind SARS-CoV-2 RNA in infected cells. To gain insights into the functions of selected RNA interactors, we applied genetic perturbation and pharmacological inhibition experiments, and mapped the contact sites on the viral RNA. This led to the identification of host dependency factors and defense strategies, which can guide the design of novel therapeutics against SARS-CoV-2.

scholarly journals Analyses of Lipid A Diversity in Gram-Negative Intestinal Bacteria Using Liquid Chromatography–Quadrupole Time-of-Flight Mass Spectrometry

Metabolites ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 197
Author(s):  
Nobuyuki Okahashi ◽  
Masahiro Ueda ◽  
Fumio Matsuda ◽  
Makoto Arita
Keyword(s):  
Mass Spectrometry ◽  
Immune Response ◽  
Liquid Chromatography ◽  
Mammalian Cells ◽  
Lipid A ◽  
Acyl Chain ◽  
Time Of Flight ◽  
Intestinal Bacteria ◽  
Gram Negative ◽  
Flight Mass Spectrometry

Lipid A is a characteristic molecule of Gram-negative bacteria that elicits an immune response in mammalian cells. The presence of structurally diverse lipid A types in the human gut bacteria has been suggested before, and this appears associated with the immune response. However, lipid A structures and their quantitative heterogeneity have not been well characterized. In this study, a method of analysis for lipid A using liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) was developed and applied to the analyses of Escherichia coli and Bacteroidetes strains. In general, phosphate compounds adsorb on stainless-steel piping and cause peak tailing, but the use of an ammonia-containing alkaline solvent produced sharp lipid A peaks with high sensitivity. The method was applied to E. coli strains, and revealed the accumulation of lipid A with abnormal acyl side chains in knockout strains as well as known diphosphoryl hexa-acylated lipid A in a wild-type strain. The analysis of nine representative strains of Bacteroidetes showed the presence of monophosphoryl penta-acylated lipid A characterized by a highly heterogeneous main acyl chain length. Comparison of the structures and amounts of lipid A among the strains suggested a relationship between lipid A profiles and the phylogenetic classification of the strains.

scholarly journals Fundamental functional differences between gyri and sulci: implications for brain function, cognition, and behavior

2021 ◽  
Vol 1 (1) ◽  
pp. 23-41
Author(s):  
Xi Jiang ◽  
Tuo Zhang ◽  
Shu Zhang ◽  
Keith M Kendrick ◽  
Tianming Liu
Keyword(s):  
Brain Function ◽  
Cell Biology ◽  
Functional Anatomy ◽  
Building Blocks ◽  
Functional Differentiation ◽  
Cortical Folding ◽  
Brain Functions ◽  
Functional Relationships ◽  
Structural Architecture ◽  
And Behavior

Abstract Folding of the cerebral cortex is a prominent characteristic of mammalian brains. Alterations or deficits in cortical folding are strongly correlated with abnormal brain function, cognition, and behavior. Therefore, a precise mapping between the anatomy and function of the brain is critical to our understanding of the mechanisms of brain structural architecture in both health and diseases. Gyri and sulci, the standard nomenclature for cortical anatomy, serve as building blocks to make up complex folding patterns, providing a window to decipher cortical anatomy and its relation with brain functions. Huge efforts have been devoted to this research topic from a variety of disciplines including genetics, cell biology, anatomy, neuroimaging, and neurology, as well as involving computational approaches based on machine learning and artificial intelligence algorithms. However, despite increasing progress, our understanding of the functional anatomy of gyro-sulcal patterns is still in its infancy. In this review, we present the current state of this field and provide our perspectives of the methodologies and conclusions concerning functional differentiation between gyri and sulci, as well as the supporting information from genetic, cell biology, and brain structure research. In particular, we will further present a proposed framework for attempting to interpret the dynamic mechanisms of the functional interplay between gyri and sulci. Hopefully, this review will provide a comprehensive summary of anatomo-functional relationships in the cortical gyro-sulcal system together with a consideration of how these contribute to brain function, cognition, and behavior, as well as to mental disorders.

scholarly journals CALINCA—A Novel Pipeline for the Identification of lncRNAs in Podocyte Disease

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 692
Author(s):  
Sweta Talyan ◽  
Samantha Filipów ◽  
Michael Ignarski ◽  
Magdalena Smieszek ◽  
He Chen ◽  
...  
Keyword(s):  
Cell Biology ◽  
Mammalian Cells ◽  
De Novo ◽  
Depth Information ◽  
Gene Products ◽  
Classical Analysis ◽  
Protein Coding ◽  
Bioinformatic Pipeline ◽  
Non Coding Rnas ◽  
Filtration Unit

Diseases of the renal filtration unit—the glomerulus—are the most common cause of chronic kidney disease. Podocytes are the pivotal cell type for the function of this filter and focal-segmental glomerulosclerosis (FSGS) is a classic example of a podocytopathy leading to proteinuria and glomerular scarring. Currently, no targeted treatment of FSGS is available. This lack of therapeutic strategies is explained by a limited understanding of the defects in podocyte cell biology leading to FSGS. To date, most studies in the field have focused on protein-coding genes and their gene products. However, more than 80% of all transcripts produced by mammalian cells are actually non-coding. Here, long non-coding RNAs (lncRNAs) are a relatively novel class of transcripts and have not been systematically studied in FSGS to date. The appropriate tools to facilitate lncRNA research for the renal scientific community are urgently required due to a row of challenges compared to classical analysis pipelines optimized for coding RNA expression analysis. Here, we present the bioinformatic pipeline CALINCA as a solution for this problem. CALINCA automatically analyzes datasets from murine FSGS models and quantifies both annotated and de novo assembled lncRNAs. In addition, the tool provides in-depth information on podocyte specificity of these lncRNAs, as well as evolutionary conservation and expression in human datasets making this pipeline a crucial basis to lncRNA studies in FSGS.

scholarly journals Quantitation of fatty acyl-coenzyme As in mammalian cells by liquid chromatography-electrospray ionization tandem mass spectrometry

2008 ◽  
Vol 49 (5) ◽  
pp. 1113-1125 ◽  
Author(s):  
Christopher A. Haynes ◽  
Jeremy C. Allegood ◽  
Kacee Sims ◽  
Elaine W. Wang ◽  
M. Cameron Sullards ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
Mammalian Cells ◽  
Fatty Acyl ◽  
Tandem Mass ◽  
Ionization Tandem Mass Spectrometry

scholarly journals Embeddings from protein language models predict conservation and variant effects

2021 ◽  
Author(s):  
Céline Marquet ◽  
Michael Heinzinger ◽  
Tobias Olenyi ◽  
Christian Dallago ◽  
Michael Bernhofer ◽  
...  
Keyword(s):  
Protein Function ◽  
Language Models ◽  
Single Amino Acid ◽  
Sequence Alignments ◽  
Multiple Sequence ◽  
Multiple Sequence Alignments ◽  
Human Proteins ◽  
Entire Sequence ◽  
Embedding Methods ◽  
Better Than

Abstract The emergence of SARS-CoV-2 variants stressed the demand for tools allowing to interpret the effect of single amino acid variants (SAVs) on protein function. While Deep Mutational Scanning (DMS) sets continue to expand our understanding of the mutational landscape of single proteins, the results continue to challenge analyses. Protein Language Models (LMs) use the latest deep learning (DL) algorithms to leverage growing databases of protein sequences. These methods learn to predict missing or marked amino acids from the context of entire sequence regions. Here, we explored how to benefit from learned protein LM representations (embeddings) to predict SAV effects. Although we have failed so far to predict SAV effects directly from embeddings, this input alone predicted residue conservation almost as accurately from single sequences as using multiple sequence alignments (MSAs) with a two-state per-residue accuracy (conserved/not) of Q2=80% (embeddings) vs. 81% (ConSeq). Considering all SAVs at all residue positions predicted as conserved to affect function reached 68.6% (Q2: effect/neutral; for PMD) without optimization, compared to an expert solution such as SNAP2 (Q2=69.8). Combining predicted conservation with BLOSUM62 to obtain variant-specific binary predictions, DMS experiments of four human proteins were predicted better than by SNAP2, and better than by applying the same simplistic approach to conservation taken from ConSeq. Thus, embedding methods have become competitive with methods relying on MSAs for SAV effect prediction at a fraction of the costs in computing/energy. This allowed prediction of SAV effects for the entire human proteome (~20k proteins) within 17 minutes on a single GPU.

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