Biology subjects

Guzman, U. H.

Publications and source records attributed to Guzman, U. H..

4 recordsLinked to original sources

bioRxiv2024

Global analysis of protein turnover dynamics in single cells

Even with recent improvements in sample preparation and instrumentation, single-cell proteomics (SCP) analyses mostly measure protein abundances, making the field unidimensional. In this study, we employ a pulsed stable isotope labeling by amino acids in cell culture (SILAC) approach to simultaneously evaluate protein abundance and turnover in single cells (SC-pSILAC). Using state-of-the-art SCP workflow, we demonstrated that two SILAC labels are detectable from [~]4000 proteins in single HeLa cells recapitulating known biology. We investigated drug effects on global and specific protein turnover in single cells and performed a large-scale time-series SC-pSILAC analysis of undirected differentiation of human induced pluripotent stem cells (iPSC) encompassing six sampling times over two months and analyzed >1000 cells. Abundance measurements highlighted cell-specific markers of stem cells and various organ-specific cell types. Protein turnover dynamics highlighted differentiation-specific co-regulation of core members of protein complexes with core histone turnover discriminating dividing and non-dividing cells with potential in stem cell and cancer research. Our study represents the most comprehensive SCP analysis to date, offering new insights into cellular diversity and pioneering functional measurements beyond protein abundance. This method distinguishes SCP from other single-cell omics approaches and enhances its scientific relevance in biological research in a multidimensional manner.

systems biology↗

bioRxiv2023

Spatiotemporal Proteomics Deciphers Functional Selectivity of EGFR ligands

The epidermal growth factor receptor (EGFR) induces different signaling outputs depending on ligand identity and biological context. This phenomenon is known as functional selectivity, but the underlying molecular mechanisms remain elusive. Here, we investigated this on a global scale and time-resolved by high-throughput multilayered proteomics integrating dynamic changes in the EGFR interaction network by proximity biotinylation using EGFR- TurboID, phosphoproteome, and proteome in response to stimulation with the six highest-affinity EGFR ligands. We obtained comprehensive temporal profiles of protein recruitment and phosphosite changes pinpointing signaling proteins differentially regulated by the six ligands with key impact on EGFR endocytic fate, e.g. degradation or recycling. Specifically, the Epsin family protein, Clint1 was identified to control the endocytic trafficking of EGFR towards degradation. Moreover, we characterized the protein interaction selectivity of EGFR C-terminally phosphorylated tyrosine residues using a panel of tyrosine mutated constructs showing STAT5 specificity for EGFR Y1173. These data provide a comprehensive resource deciphering functional selectivity of EGFR signaling to support discovery of novel drug targets.

molecular biology↗

bioRxiv2023

Narrow-window DIA: Ultra-fast quantitative analysis of comprehensive proteomes with high sequencing depth

Mass spectrometry (MS)-based proteomics aims to characterize comprehensive proteomes in a fast and reproducible manner. Here, we present an ultra-fast scanning data-independent acquisition (DIA) strategy consisting on 2-Th precursor isolation windows, dissolving the differences between data-dependent and independent methods. This is achieved by pairing a Quadrupole Orbitrap mass spectrometer with the asymmetric track lossless (Astral) analyzer that provides >200 Hz MS/MS scanning speed, high resolving power and sensitivity, as well as low ppm-mass accuracy. Narrow-window DIA enables profiling of up to 100 full yeast proteomes per day, or [~]10,000 human proteins in half-an-hour. Moreover, multi-shot acquisition of fractionated samples allows comprehensive coverage of human proteomes in [~]3h, showing comparable depth to next-generation RNA sequencing and with 10x higher throughput compared to current state-of-the-art MS. High quantitative precision and accuracy is demonstrated with high peptide coverage in a 3-species proteome mixture, quantifying 14,000+ proteins in a single run in half-an-hour. TeaserAccurate and precise label-free quantification with comprehensive proteome coverage using narrow-window DIA

systems biology↗

bioRxiv2022

Loss of N-terminal acetyltransferase A activity induces thermally unstable ribosomal proteins and increases their turnover

Protein N-terminal (Nt) acetylation is one of the most abundant modifications in eukaryotes, covering [~]50-80 % of the proteome, depending on species. Cells with defective Nt-acetylation display a wide array of phenotypes such as impaired growth, mating defects and increased stress sensitivity. However, the pleiotropic nature of these effects has hampered our understanding of the functional impact of protein Nt-acetylation. The main enzyme responsible for Nt-acetylation throughout the eukaryotic kingdom is the N-terminal acetyltransferase NatA. Here we employed a multi-dimensional proteomics approach to analyze Saccharomyces cerevisiae lacking NatA activity, which caused global proteome remodeling. Pulsed-SILAC experiments revealed that NatA-deficient strains consistently increased degradation of ribosomal proteins compared to wild type. Explaining this phenomenon, thermal proteome profiling uncovered decreased thermostability of ribosomes in NatA-knockouts. Our data are in agreement with a role for Nt-acetylation in promoting stability for parts of the proteome by enhancing the avidity of protein-protein interactions and folding. TeaserA multidimensional proteomics approach reveals the effect of N-terminal acetylation on Saccharomyces cerevisiae cytosolic ribosomal proteins.

biochemistry↗