Biology subjects

Nicola, J. P.

Publications and source records attributed to Nicola, J. P..

3 recordsLinked to original sources

bioRxiv2022

Structural insights into sodium/iodide symporter (NIS) substrate binding and specificity

The sodium/iodide symporter (NIS) is the essential plasma membrane protein that mediates active iodide (I-) transport into the thyroid gland, the first step in the biosynthesis of the thyroid hormones--the master regulators of intermediary metabolism. NIS couples the inward translocation of I- against its electrochemical gradient to the inward transport of Na+ down its electrochemical gradient. For nearly 50 years before its molecular identification, NIS was already the molecule at the center of the single most effective internal radiation cancer therapy ever devised: radioiodide (131I-) treatment for thyroid cancer. Mutations in NIS cause congenital hypothyroidism, which must be treated immediately after birth to prevent stunted growth and cognitive deficiency. To date, the structure of NIS has been unknown. Here, we report three structures of rat NIS, determined by single-particle cryo-electron microscopy (cryo-EM): one with no substrates bound, one with 2 Na+ and 1 I- bound, and one with 1 Na+ and the oxyanion perrhenate bound. Structural analyses, functional characterization, and computational studies reveal the substrate binding sites and residues key for transport activity. Our results yield insights into how NIS selects, couples, and translocates anions--thereby establishing a framework for understanding NIS function--and into how it transports different substrates with different stoichiometries and releases substrates from its substrate-binding cavity into the cytosol.

biophysics↗

bioRxiv2021

MotSASi: Functional Short Linear Motifs (SLiMs) prediction based on genomic single nucleotide variants and structural data

Short linear motifs (SLiMs) are key to cell physiology mediating reversible protein-protein interactions. Precise identification of SLiMs remains a challenge, being the main drawback of most bioinformatic prediction tools their low specificity (high number of false positives). An important, usually overlooked, aspect is the relation between SLiMs mutations and disease. The presence of variants in each residue position can be used to assess the relevance of the corresponding residue(s) for protein function, and its (in)tolerance to change. In the present work, we combined sequence variant information and structural analysis of the energetic impact of single amino acid substitution (SAS) in SLiM-Receptor complex structure, and showed that it significantly improves prediction of true functional SLiMs. Our strategy is based on building a SAS tolerance matrix that shows, for each position, whether one of the possible 19 SAS is tolerated or not. Herein we present the MotSASi strategy and analyze in detail 4 SLiMs involved in intracellular protein trafficking. Our results show that inclusion of variant and sequence information significantly improves both prediction of true SLiMs and rejection of false positives, while also allowing better classification of variants inside SLiMs, a results with a direct impact in clinical genomics.

molecular biology↗

bioRxiv2019

Neonatal endotoxin stimulation was associated with long- term innate immune markers and an anti-allergic response in bronchiolar epithelium in spite of allergen challenge

Asthma is a heterogeneous disease underlying different medical processes, being the allergic asthma, with an early-onset in childhood, the most common type. In this phenotype, the continuous exposure to allergens produces a Th2-driven airway remodeling process that leads to symptoms and pathophysiological changes in asthma. Strategies as the avoidance of aeroallergen exposure in early life have been tested to prevent asthma, without a clear success. Alongside, several mouse models of aeroallergen challenge have dissected potential homeostatic responses by which environmental microbial stimulation reduces the subsequent allergic inflammation in the offspring. This suggests the onset of underlying preventive mechanisms in the beginning of asthma that have not been fully recognized. In this study, we aimed to evaluate if neonatal LPS-induced stimulus in epithelial host defenses could contribute to the prevent asthma in adult Balb/c mice. For this purpose, we studied the response of bronchiolar club cells (CC) that are situated in the crossroads of the host defense and allergic inflammation, and express specific pro and antiallergic proteins. LPS stimulus in the neonatal life intensified the production of TLR-4, TNF, and natural anti-allergic products (CCSP and SPD), changes that contributed to prevent asthma triggering in adulthood. At epithelial level, CC skipped the mucous metaplasia, declining the overproduction of mucin via the EGFR pathway and the mice expressed normal breathing patterns in front of OVA challenge. Furthermore, the overexpression of TSLP, an epithelial pro-Th2 cytokine was blunted and normal TSLP and IL-4 levels were found in bronchoalveolar lavage (BAL). Complementing this shift, we also detected lower eosinophilia in BAL while an increase in phagocytes as well as in regulatory cells (CD4+CD25+FOXP3+ and CD4+IL-10+) was seen, whit an elevation in IL-12 and TNF secretion. Summarizing, our study pointed to stable asthma-preventive effects promoted by neonatal LPS-stimulation; the main finding was the increase of several anti-Th2 specific proteins at epithelial level, together with an important diminution of pro-Th2 TSLP, conditions that promoted changes in the local immune response with Treg. We thus evidenced several anti-allergic dynamic mechanisms overlying in the epithelium that could be favored in an adequate epidemiological environment

cell biology↗