Biology subjects

Vilaseca, M.

Publications and source records attributed to Vilaseca, M..

4 recordsLinked to original sources

bioRxiv2024

Quantification of histone H1 subtypes using targeted proteomics.

Histone H1 is involved in the regulation of chromatin structure. Human somatic cells express up to seven subtypes. The variability in the proportions of somatic H1s (H1 complement) is one evidence supporting their functional specificity. Alterations in the protein levels of different H1 subtypes have been observed in cancer, suggesting their potential as biomarkers and that they might play a role in disease development. We have developed a mass spectrometry based (MS) parallel reaction monitoring (PRM) assay suitable for the quantification of H1 subtypes. Our PRM method is based on the quantification of unique peptides for each subtype, providing high specificity. Evaluation of the PRM performance on three human cell lines showed high reproducibility and sensitivity. Quantification values agreed with the electrophoretic and Western blot data, indicating the accuracy of the method. We used PRM to quantify the H1 complement in peripheral blood samples of healthy individuals and chronic myeloid leukemia (CML) patients. Our preliminary data revealed differences in the H1 complement between responders and non-responder CML patients and suggest that the H1 content could help predicting imatinib response.

biochemistry↗

bioRxiv2022

Characterization of p38a signaling networks in cancer cells using quantitative proteomics and phosphoproteomics

p38 (encoded by MAPK14) is a protein kinase that regulates cellular responses to almost all types of environmental and intracellular stresses. Upon activation, p38 phosphorylates many substrates both in the cytoplasm and nucleus, allowing this pathway to regulate a wide variety of cellular processes. While the role of p38 in the stress response has been widely investigated, its implication in cell homeostasis is less understood. To investigate the signaling networks regulated by p38 in normally proliferating cancer cells, we performed quantitative proteomic and phosphoproteomic analyses in breast cancer cells in which this pathway had been either genetically targeted or chemically inhibited. Our study identified with high confidence 35 proteins and 82 phosphoproteins (114 phosphosites) that are modulated by p38, and highlighted the implication of various protein kinases, including MK2 and mTOR, in the p38-regulated signaling networks. Moreover, functional analyses revealed an important contribution of p38 to the regulation of cell adhesion, DNA replication and RNA metabolism. Indeed, we provide experimental evidence supporting that p38 negatively regulates cell adhesion, and showed that this p38 function is likely mediated by the modulation of the adaptor protein ArgBP2. Collectively, our results illustrate the complexity of the p38 regulated signaling networks, provide valuable information on p38-dependent phosphorylation events in cancer cells, and document a mechanism by which p38 can regulate cell adhesion.

biochemistry↗

bioRxiv2019

Evolution toward maximum transport capacity of the Ttg2 ABC system in Pseudomonas aeruginosa

In Pseudomonas aeruginosa, Ttg2D is the soluble periplasmic phospholipid-binding component of an ABC transport system thought to be involved in maintaining the asymmetry of the outer membrane. The crystallographic structure of Ttg2D at 2.5[A] resolution reveals that this protein can bind two diacyl phospholipids. Native and denaturing mass spectrometry experiments confirm that Ttg2D binds two phospholipid molecules, which may have different head groups. Analysis of the available structures of Ttg2D orthologs allowed us to classify this protein family as a novel substrate-binding protein fold and to venture the evolutionary events that differentiated the orthologs binding one or two phospholipids. In addition, gene knockout experiments in P. aeruginosa PAO1 and multidrug-resistant strains show that disruption of this system leads to outer membrane permeabilization. This demonstrates the role of this system in low-level intrinsic resistance against certain antibiotics that use a lipid-mediated pathway to permeate through membranes.

microbiology↗

bioRxiv2019

Measurement of ocular transmission in living human eyes with a double-pass system

PurposeTo develop a methodology based on a double-pass system to obtain useful information about the transmission of ocular media, performing noninvasive measures in vivo.\n\nMethodsThis noninvasive procedure consists of recording double-pass images at different voltages of a laser diode of 780 nm and the determination of the scattering in an area between 25 and 35 arc minutes of each image.\n\nResultsOcular scattering showed a linear behavior respect to the voltage of the laser and the slope of the linear fit was proportional to the transmittance squared of the media evaluated. The relationship between the ocular light scattering of the images and the transmittance values of several filters located into an artificial eye was used as a calibration function. The measurements performed in a group of ten subjects with ages between 25 and 45 years old presented a mean direct transmittance of the whole eye including retina of 42.7 %, which agrees with the bibliography. No differences between dark eyes and light eyes were found.\n\nConclusionWe have developed a method to determine the transmittance of the human eye in vivo for a wavelength of 780 nm using the double-pass method, commonly used for the determination of the optical quality of an eye.

bioengineering↗