Biology subjects

Bradai, M.

Publications and source records attributed to Bradai, M..

3 recordsLinked to original sources

bioRxiv2025

Multi-fiber array-based photometry system for multi-regional functional mapping in the mouse brain

Mesoscopic functional brain mapping is essential to better understanding of various brain functions and dysfunctions. However, accessing distributed neural circuits in mammalian brain regions remains a significant challenge. While fiber photometry is a versatile optical approach, existing methods often suffer from invasiveness and scalability. Here we present an affordable multi-fiber array (MFA)-based photometry system to monitor neural signals across multiple regions. Our system comprises a custom-designed MFA utilizing 50-{micro}m diameter optical fibers and off-the-shelf optical components. To demonstrate the systems versatility, we monitored GABAergic population activity using jGCaMP8s across multiple brain regions in head-fixed, awake mice. By combining with pupillometry, we identified state-dependent, region-specific GABAergic dynamics. Our MFA-based photometry system opens new avenues for investigating state-dependent neural dynamics at the mesoscopic level. To facilitate wider adoption, all codes and resources are publicly available on GitHub (https://github.com/Sakata-Lab/MFA).

neuroscience↗

bioRxiv2025

Barley C2-Domain Abscisic Acid-Related protein CARa supports susceptibility to Blumeria hordei and localizes to the extrahaustorial membrane

Rho GTPases are key regulators of cellular signalling processes in eukaryotes. In plants, Rho of plants (ROP) proteins function in cell polarization, hormone signalling, and plant immunity or susceptibility to diseases. The barley (Hordeum vulgare) ROP protein RACB is involved in susceptibility towards the biotrophic ascomycete fungus Blumeria hordei (Bh) and supports the accommodation of fungal haustoria. In healthy barley, RACB plays a role in cell development, a function that the pathogen may co-opt for cellular ingrowth of its haustorium into intact epidermal cells of barley. The majority of identified functions of GTP-bound activated RACB appear to be mediated by scaffold proteins. One of them, the ROP Interactive Partner b (RIPb, synonym: Interactor of Constitutive Active ROP b, ICRb) binds to RACB-GTP and co-localizes with RACB at the site of fungal host cell entry. RIPb interacts with RACB-GTP via its C-terminal coiled-coil CC2 domain (RIPbCC2) at the plasma membrane. Here, we show that a barley Calcium-Dependent Phospholipid Binding 2 (C2)-Domain Abscisic Acid-Related protein (CARa) interacts with RIPb and its RIPbCC2 domain in planta. Transient knockdown of CARa renders barley epidermal cells less susceptible to invasion by Bh, whereas overexpression supports fungal haustorium accomodation. Upon fungal attack, CARa is recruited to the site of fungal attack and localizes around the haustorial neck and at the extrahaustorial membrane. These findings further support that Bh profits from host ROP signalling components and CARa. CARa might connect RACB-RIPb-signalling to membrane organization for support of fungal infection structures in barley epidermal cells.

plant biology↗

bioRxiv2024

Barley resistance and susceptibility to fungal cell entry involve the interplay of ROP signaling with phosphatidylinositol-monophosphates

Rho-of-plant small GTPases (ROPs) are regulators of plant polar growth and of plant-pathogen interactions. The barley ROP, RACB, is involved in susceptibility towards infection by the barley powdery mildew fungus Blumeria hordei (Bh) but little is known about the cellular pathways that connect RACB-signaling to disease susceptibility. Here we identify novel RACB interaction partners of plant or fungal origin by untargeted co-immunoprecipitation of constitutively active (CA) RACB tagged by green-fluorescent protein from Bh-infected barley epidermal layers and subsequent analysis by liquid chromatography-coupled mass spectrometry. Three of immunoprecipitated proteins, a plant phosphoinositide phosphatase, a plant phosphoinositide phospholipase and a putative Bh-effector protein are involved in the barley-Bh-pathosystem and support disease resistance or susceptibility, respectively. RACB and its plant interactors bind to overlapping anionic phospholipid species in vitro, and in case of RACB, this lipid-interaction is mediated by its carboxy-terminal polybasic region (PBR). Fluorescent markers for anionic phospholipids show altered subcellular distribution in barley cells during Bh-attack and under expression of a RACB-binding fungal effector. Phosphatidylinositol 4-phosphate, phosphatidylinositol 3,5-bisphosphate and phosphatidylserine show a distinct enrichment at the haustorial neck region, suggesting a connection to subcellular targeting of RACB at this site. The interplay of ROPs with anionic phospholipids and phospholipid-metabolizing enzymes may thus enable the subcellular enrichment of components pivotal for success or failure of fungal penetration.

plant biology↗