Biology subjects

Espinoza, V.

Publications and source records attributed to Espinoza, V..

2 recordsLinked to original sources

bioRxiv2021

Hypusinated eIF5A is required for the translation of collagen

The evolutionary conserved elongation factor eIF5A is required for the translation of mRNAs that encode protein sequences with consecutive prolines or combined with glycine and charged amino acids. Mammalian collagens are enriched in putative eIF5A-dependent Pro-Gly-containing tripeptides. Here, we show that eIF5A is needed for heterologous expression of collagen in yeast, and using a dual luciferase reporter system we confirmed that eIF5A depletion interrupts translation at Pro-Gly-collagenic motifs. Using mouse fibroblasts, we showed that depletion of active eIF5A reduced collagen 1 (Col1a1) content, which became concentrated around the nuclei, in contrast to a stronger and all over the cell collagen signal in untreated cells. Active eIF5A-depleted mouse fibroblast showed upregulation of endoplasmic reticulum (ER) stress markers, suggesting retention of partially synthesized Col1a1 in the ER. A dramatically lower level of Col11 protein was also observed in functional eIF5A-depleted human hepatic stellate cells treated with the profibrotic cytokine TGF-{beta}1. Our results show that collagen expression requires eIF5A and imply its potential as a target for regulating collagen production in fibrotic diseases.

molecular biology↗

bioRxiv2020

Multidimensionality in the thermal niches of dung beetles could limit species' responses to temperature changes

Understanding the consequences of climate change requires understanding how temperature controls species responses across key biological aspects, as well as the coordination of thermal responses across these aspects. We study the role of temperature in determining the species diel, seasonal, and geographical occurrence, using dung beetles as a model system. We found that temperature has relatively low -but not negligible- effects in the three spatiotemporal scales, once accounting for alternative factors. More importantly, the estimated thermal responses were largely incongruent across scales. This shows that species have multidimensional thermal niches, entailing that adjustments to fulfil temperature requirements for one biological aspect, such as seasonal ontogenetic cycles, may result in detrimental effects on other aspects, like diel activity. These trade-offs can expose individuals to inadequate temperatures, reducing populations performance. Paradoxically, the relatively weak effects of temperature we found may have serious consequences for species responses to warming if temperature regulates essential aspects of species biology in divergent ways.

ecology↗