Biology subjects

ROY, A.

Publications and source records attributed to ROY, A..

3 recordsLinked to original sources

bioRxiv2026

Wind pattern oscillations explain seabird movements at-sea: a nested multiscale approach

Wind has a strong influence on the flight characteristics, movements, energetics, demography, life-history traits and biogeography of flying animals. With climate change affecting atmospheric circulation patterns at different time scales, understanding the links between wind and animal movements is crucial for predicting its impact on flying biodiversity. Most studies on the relationship between wind and seabird movements have, however, focused on local scales, exploring birds perceptive sensitivity to local wind. In this study, we examine low-level wind pattern oscillations in the Southern Indian Ocean at multiple time scales to explain the local- to large-scale movements of the Amsterdam albatross. Adult individuals exhibited smooth trajectories, strongly correlated with seasonal, intra-seasonal or interannual wind oscillations. Conversely, younger individuals displayed more erratic and exploratory movements, often being swept away by eastward moving low-pressure systems at a synoptic time scale. Our results suggest that Amsterdam albatrosses can learn and adapt to the annual and monthly low-level wind climatology and interannual variability of the Southern Indian Ocean. This also highlights the importance of investigating seabird movements in relation to broader-scale wind patterns to support their conservation in a changing climate due to human activities. A robust assessment of regional circulation response to climate change for upcoming decades could help project the impact of climate change on seabird movements and mitigate its effects.

ecology↗

bioRxiv2025

AKNA drives neural stem cell fate transition through differential localization and coordinating the modulation of chromatin from H3K27me3 to H3K27ac

Neuronal stem cells (NSCs) play pivotal role in adult neurogenesis, however, detail mechanisms of obtaining pluripotency or undergoing differentiation remain unknown. Herein, how AT-hook protein AKNA regulates pluripotency and stemness in neuroblastoma cells is demonstrated by gene knockdown, immunofluorescence, chromatin immunoprecipitation (ChIP), localization of AKNA, signaling interactions and transcriptional activity. AKNA was abundant and mostly nuclear during induction of pluripotency and its knockdown reduced stemness, even in presence of other pluripotency factors, including OCT4 and SOX2. During the course of induction of differentiation, AKNA remain localized in the cytosol, essential for regulated differentiation. Cytosolic retention of AKNA is possibly driven by FAK signaling. In the nucleus, AKNA promotes KDM6B demethylase for H3K27me3 demethylation to H3K27, and subsequently promotes CBP/p300 to acetylate H3K27 to H3K27ac deposition on promoter region of respective genes to trigger their transcription. Data obtained from knockdown and overexpression of AKNA and KDM6B further reinforce its importance that, they physically interact to drive pluripotency and stemness. These findings establish AKNA as a critical regulator for NSCs fate determination in association with epigenetic modifiers and signaling pathway, offering potential targets for neuroblastoma therapies and regenerative medicines for neurodegenerative diseases.

molecular biology↗

bioRxiv2025

Influenza virus recruits PKCa-MEK1-ERK2 complex to regulate nuclear export of viral ribonucleoproteins and promote virus replication.

Host kinases had long been implicated in regulating various steps of influenza virus replication cycle. Previous studies showed that the protein kinase C (PKC) activated mitogen activated protein kinase (MEK)/ extracellular signal-regulated kinase (ERK) cascade promotes nuclear export of viral ribonucleoprotein complexes (RNPs), by triggering phosphorylation of viral nucleoprotein (NP), the major constituent of RNPs. But, the molecular mechanism by which PKC coordinates with specific members of the MAPK pathway to regulate NP phosphorylation remained obscure. Additionally, the molecular interactions of these kinases with NP and the spatiotemporal dynamics of such interactions have never been investigated. Here we unravel the existence of a tripartite PKC-MEK1-ERK2 complex that associates with influenza virus NP and mediates its phosphorylation during the course of infection. Using an analogue sensitive kinase, we show that ERK2 can directly phosphorylate NP at specific serine-threonine residues, which promote vRNP nuclear export and are indispensable for virus propagation. PKC not only activates the MAP kinase, but acts as a scaffold for mediating stable interactions between MEK1, ERK2 and NP, thereby forming an NP associated multi-kinase complex that facilitate its phosphorylation. This multiprotein complex localizes in the nucleus early during infection but into cytoplasm at later stages and overexpression of a dominant negative PKC blocks this complex formation, NP phosphorylation, vRNP export and progeny virus production. These data not only unravel a complex network of virus-host interactions supporting different influenza A and B virus replication, but also shade light upon an unexplored avenue of PKC mediated regulation MAPK pathway. SignificanceThe substrate specificity of kinases is the key for precise regulation of various signaling cascades and can be governed by direct kinase-substrate interaction or indirect interaction mediated through scaffolding or anchoring proteins. This study shows how influenza virus exploit a well-known cellular kinase, PKC, as a scaffold protein to activate and recruit other cellular kinases, MEK1 and ERK2, upon viral replication machinery, RNPs. This RNP associated multi-kinase complex facilitates ERK2 mediated phosphorylation of viral NP protein, which regulates RNP nuclear export and ultimately the production of new virion particles. This work elucidates an unconventional mechanism of kinase-substrate interaction which is critical for influenza virus replication and hence paves the way towards the development of novel host directed anti-influenza therapy.

molecular biology↗