Biology subjects

Araujo, F.

Publications and source records attributed to Araujo, F..

4 recordsLinked to original sources

bioRxiv2026

Heterologous engineering of receptors using OrthoRep (HERO) for directed evolution of GPCRs in yeast

Engineering G protein-coupled receptors (GPCRs) for biosensing applications remains challenging due to structural and functional constraints when such proteins are expressed in a heterologous host. OrthoRep offers the continuous accumulation and selection of signal-enhancing mutations in yeast, yet it has not been applied to GPCR evolution. We apply OrthoRep-driven mutagenesis to evolve opioid GPCRs and improve yeast-based biosensors: first, we express the human -opioid receptor (OPRM1) on the OrthoRep p1 plasmid and couple ligand activation to growth. Serial cell passaging of the biosensor generated functionally diverse mutants. However, mutations that decouple receptor activation from selection arose over longer passaging campaigns, halting evolution. We resolve this issue using a site-specific recombinase that re-introduces evolved variants onto the p1 landing pad of an unmutated biosensor, allowing continued selection. This led to an ~18-fold improvement in sensitivity of a mutant OPRM1 over wt-OPRM1. Additional polymerases were added to the platform, broadening the mutational profiles available. Assembling these components forms the platform we call HERO (Heterologous Engineering of Receptors using OrthoRep). Lastly, we deploy HERO using automation to improve the human {delta}-opioid receptor's weak response to an agonist by ~40-fold. Sensitivity also improved for a structurally dissimilar ligand assayed on the same evolved variants.

synthetic biology↗

bioRxiv2026

AKAP5 and Caveolin-1 organize opposing nanodomains that regulate smooth muscle contraction and blood pressure

TRPV4 ion channels in vascular smooth muscle cells (SMCs) are crucial regulators of blood pressure, and their functional effects are differentially shaped by their signaling partners. However, the mechanisms by which TRPV4 channels are compartmentalized into distinct signaling nanodomains with opposite impacts on blood pressure remain unclear. Here, we identify the scaffolding proteins that compartmentalize TRPV4 channels into discrete nanometer-scale signaling domains at the SMC plasma membrane and define how these nanodomains produce opposing effects on vasoconstriction and blood pressure. We show that AKAP5 anchors a nanodomain linking 1-adrenergic receptors, protein kinase C and TRPV4 channels, thereby driving sympathetic vasoconstriction and blood pressure elevation. In contrast, caveolin-1 promotes a mechanosensitive nanodomain comprising Piezo1, TRPV4, and BK channels that mediates vasodilation and a decrease in blood pressure. In hypertension, AKAP5-dependent constrictor nanodomains are hyperactive, whereas caveolin-1-based dilator nanodomains are hypoactive, shifting the balance toward pathological vasoconstriction. These findings reveal fundamental mechanisms that organize smooth muscle TRPV4 channels into spatially and functionally distinct nanodomains regulating blood pressure and show how disruption of this organization contributes to blood pressure elevation in hypertension.

physiology↗

bioRxiv2024

Simulated larvae dispersion of the invasive sun-coral (Tubastrea spp.) along Rio de Janeiro's coast: the role of submesoscale filaments on offshore transport and connectivity

The spread of invasive species in marine ecosystems is a growing global concern, particularly in regions with high economic and ecological importance. sun corals (Tubastraea spp.) are scleractinians native to the Pacific Ocean that have spread along most of the Brazilian coast. This exotic species initially established populations in Rio de Janeiro, reaching high levels of abundance. Although the ecological aspects and impacts caused by this organism have been studied in detail, the natural mechanisms that drive its dispersal have attracted little attention. In this research, we focus on the offshore transport of sun coral larvae between Cabo de Sao Tome and Ilha Grande Bay, RJ, investigating how submesoscale oceanographic features such as filaments, eddies and upwelling influence connectivity among different population. High-resolution numerical simulations were used to model the coastal dynamics, incorporating the influence of the Brazil Current, wind-driven circulation, and submesoscale structures. Larval dispersal was examined under different wind scenarios, including northeasterly winds that drive southward currents which enhance offshore transport via submesoscale filaments. Results show that submesoscale features, particularly filaments emerged from upwelling regions, play a significant role on sun coral larvae dispersion. These features act as pathways that connect larvae from coastal to offshore oil exploration areas, highlighting the importance of both natural and anthropogenic processes for the dissemination of this invasive species. This research provides critical insights into the ecological mechanisms governing the spread of invasive marine species, emphasizing the need for integrated coastal management strategies. Understanding how physical processes drive larval transport is essential for developing targeted control measures to mitigate the impact of invasive species like sun coral on native ecosystems and local economies. Furthermore, the study underscores the importance of monitoring both natural and anthropogenic influences on marine bioinvasions, particularly in regions with significant offshore industrial activities.

ecology↗

bioRxiv2022

Roles of the 5-HT2C receptor on zebrafish sociality

Serotonin (5-HT) receptors have been implicated in social behavior in vertebrates. Zebrafish (Danio rerio) have been increasingly being used behavioral neuroscience to study the neurobiological correlates of behavior, including sociality. Nonetheless, the role of 5-HT2C receptors in different social functions were not yet studied in this species. Zebrafish were treated with the agonist MK-212 (2 mg/kg) or the antagonist RS-102221 (2 mg/kg) and tested in the social interaction and social novelty tests, conditional approach test, or mirror-induced aggressive displays. MK-212 increased preference for an unknown conspecific in the social investigation test, but also increased preference for the known conspecific in the social novelty test; RS-102221, on the other hand, decreased preference in the social investigation test but increased preference for the novel conspecific in the social novelty test. MK-212 also decreased predator inspection in the conditional approach test. While RS-102221 decreased time in the display zone in the mirror-induced aggressive display test, it increased display duration. Overall, these results demonstrate the complex role of 5-HT2C receptors in different social contexts in zebrafish, revealing a participation in social plasticity in vertebrates.

neuroscience↗