Biology subjects

Zabeo, D.

Publications and source records attributed to Zabeo, D..

4 recordsLinked to original sources

bioRxiv2025

Intracellular Regulation of a Serotonin-Gated Ion Channel Links Receptor Trafficking to Memory

Learning and memory arise from synaptic plasticity, the ability of neurons to modify connectivity through experience-dependent changes in receptor localisation and signalling. Here, we identify a short intracellular motif within the serotonin-gated ion channel LGC-50 that links molecular receptor dynamics to behavioural plasticity in Caenorhabditis elegans. Deletion of residues 363-379 in the intracellular M3-4 loop caused receptor clustering in intracellular compartments and abolished learning-induced redistribution without altering receptor function or immediate memory recall. Interestingly, animals expressing the truncated receptor failed to retrieve aversive memories one hour after training, revealing a role for receptor trafficking in memory stability. Combining molecular, ultrastructural and behavioural analyses in vivo, we show how intracellular receptor motifs govern experience-dependent plasticity. These findings demonstrate that precise receptor localisation and trafficking shape neural circuit adaptation and reveal a conserved mechanism by which receptor dynamics support the persistence and retrieval of memory across species.

neuroscience↗

bioRxiv2024

Genomic and structural insights into Jyvaskylavirus, the first giant virus isolated from Finland

Giant viruses of protists are a diverse and likely ubiquitous group of organisms. Here, we describe Jyvaskylavirus, the first giant virus isolated from Finland. This clade B marseillevirus was found in Acanthamoeba castellanii from a composting soil sample in Jyvaskyla, Central Finland. Its genome shares similarities with other marseilleviruses. Helium ion microscopy and electron microscopy of infected cells unraveled stages of the Jyvaskylavirus lifecycle. We reconstructed the Jyvaskylavirus particle to 6.3 [A] resolution using cryo-EM. The [~]2,500 [A] diameter virion displays structural similarities to other Marseilleviridae giant viruses. The capsid comprises of 9,240 copies of the major capsid protein ORF184, which possesses a double jellyroll fold arranged in trimers forming pseudo-hexameric capsomers. Below the capsid shell, the internal membrane vesicle encloses the genome. Through cross-structural and -sequence comparisons with other Marseilleviridae using AI-based software in model building and prediction, we elucidated ORF142 as the penton protein, which plugs the twelve vertices of the capsid. Five additional ORFs were identified, with models predicted and fitted into densities that either cap the capsomers externally or stabilize them internally. The isolation of Jyvaskylavirus suggests that these viruses may be widespread in the boreal environment and provide structural insights extendable to other marseilleviruses.

microbiology↗

bioRxiv2019

Axonemal doublet microtubules can split into two complete singlets in human sperm flagellum tips

Motile flagella are crucial for human fertility and embryonic development. The distal tip of the flagellum is where growth and intra-flagellar transport are coordinated. In most, but not all, model organisms the distal tip includes a "singlet region", where axonemal doublet microtubules terminate and only complete A-tubules extend as singlet microtubules to the tip. How a human flagellar tip is structured is unknown. Here, the flagellar tip structure of human spermatozoa was investigated by cryo-electron tomography, revealing the formation of two complete singlet microtubules from both the A-tubule and B-tubule of doublet microtubules. This different tip arrangement in human spermatozoa shows the need to investigate human flagella directly in order to understand their role in our health and disease.

cell biology↗

bioRxiv2016

Exosomes purified from a single cell type have diverse morphology and composition

Extracellular vesicles (EVs) are produced by all known organisms and have important roles in cell communication and physiology. Exosomes are known in the literature to be small round EVs (40 to 100 nm in diameter) and are commonly purified with a serial ultracentrifugation protocol followed by density gradient floatation. Great morphological diversity has been described before regarding EVs found in body fluids such as blood plasma, breast milk and ejaculate. However, a detailed morphological analysis has never been performed on exosomes purified from a single cell type.\n\nTherefore, the aim of this study was to analyze and quantify via multiple electron microscopy techniques the morphology of exosomes purified from the human mast cell line HMC-1. The results revealed a novel spectrum of diversity in exosomes, which suggests that subpopulations of exosomes with different and specific functions might also exist. Our findings therefore argue that a new and more efficient way of defining exosome subpopulations is necessary. A system was proposed where exosomes were classified into nine different categories according to their size and shape. Three additional morphological features could also be found in exosomes regardless of their classification.\n\nThese findings show that morphological diversity is found among exosomes purified from a single cell line, similarly to what was previously observed for EVs in body fluids. This knowledge can help improving the interpretation of experimental results and widening our general understanding of the biological functions of exosomes.

cell biology↗