Biology subjects

Gonzalez-Perez, M. P.

Publications and source records attributed to Gonzalez-Perez, M. P..

4 recordsLinked to original sources

bioRxiv2026

Membrane proteomics of the Drosophila circadian neural network

Circadian behaviors are controlled by dedicated brain pacemaker neurons, whose activity oscillate during the day and the night. The Drosophila brain contains ca. 240 such neurons. Their molecular clock is synchronized, but the phase of their rhythmic neural activity differs dramatically between functional groups. This explains how specific circadian neurons can for example promote morning or evening locomotor activity. To understand in depth how the circadian network functions, we surveyed its membrane proteome in the morning and evening, using in situ protein labeling and mass spectrometry. In addition to detecting known regulators of circadian behavior, we identified novel membrane or membrane-associated proteins present in circadian neurons. Through genetic screens, we found that many of these proteins regulate circadian behavior. In particular, Piezo regulates morning activity specifically under short photoperiod, and its loss compromises the structural plasticity of the clock neurons controlling locomotion at dawn. Our work thus illustrates the power of proteome-guided genetic screens to understand the mechanisms underlying circadian behavior.

neuroscience↗

bioRxiv2025

Seipin mediates Perilipin-1 recruitment to lipid droplets to preserve human adipocyte identity

Congenital generalized lipodystrophy type 2 (CGL2) is caused by mutations in the BSCL2 gene, which encodes the protein seipin. However, how seipin loss causes adipose tissue failure remains unclear. Using human adipocyte progenitor cells capable of robust differentiation in vitro and in vivo, we reveal two unexpected findings that redefine CGL2 pathogenesis. First, seipin is dispensable for lipid droplet biogenesis but essential for recruiting the major adipocyte scaffold protein Perilipin 1 (PLIN1) to the lipid droplet surface. Second, we discover that the integrity of the lipid droplet serves as an organelle to nucleus quality control checkpoint enforcing adipocyte identity. Without seipin-dependent PLIN1 recruitment, adipocytes exhibit enhanced lipolysis and ceramide accumulation, triggering an unexpected cellular response of de-differentiation into a progenitor-like state. From this de-differentiated state, cells can undergo additional cycles of differentiation and de-differentiation upon repeated adipogenic stimuli. However, some cells escape de-differentiation, instead forming a single large droplet and displaying severe cellular structural abnormalities. Consistent with this model, we find functional adipose tissue can form in vivo from seipin-deficient cells, yet ultimately fails. These findings resolve conflicting models of CGL2 pathogenesis by reframing seipin as a regulator of PLIN1 recruitment, rather than droplet formation per se, and reveal the fundamental role of lipid droplet integrity in the development of functional human adipocytes.

cell biology↗

bioRxiv2025

Proteomic characterization of neuronal extracellular vesicle interactomes in Alzheimer's disease mouse model through TurboID-based proximity labeling

Extracellular vesicles (EVs) are critical mediators of neuronal communication and have been implicated in propagating pathological processes in neurodegenerative diseases, including Alzheimers disease (AD). However, the molecular interactome of neuronal EVs in vivo remains poorly defined. Here, we employed TurboID-CD9-based proximity biotinylation to label and capture EV-interacting proteins in the hippocampus of wild-type (WT) and APPNLGF knock-in AD mouse models. Adeno-associated viral delivery of hSyn1 promoter-driven TurboID-CD9 enabled neuron-specific EV tagging, followed by in vivo biotinylation and affinity purification of labeled proteins. Proteomic analysis using data independent acquisition liquid chromatography - mass spectrometry identified 5,502 proteins, with enriched pathways involving synaptic transmission, vesicle trafficking, and inhibitory neurotransmission. Comparative analyses revealed robust enrichment of GABAergic signaling components, including GABAA receptor subunits (Gabrb3, Gabra1, Gabbr2), Ncam1, and chloride transporters, in both WT and APPNLGF EV interactomes, with additional disease-associated proteins (Mapt, Snca) and potassium channel enrichment observed in APPNLGF mice. Proximity ligation assays validated direct EV-associated biotinylation of Ncam1, Gabrb3, and Gad1, with Gad1 showing significant upregulation in the APPNLGF cohort. In silico HADDOCK docking supported stable interactions between CD9 and these target proteins, revealing plausible EV-protein interfaces. These findings define the in vivo neuronal EV interactome and its remodeling in amyloid pathology, implicating EV-associated GABAergic and ion channel proteins in network excitability regulation. This work establishes a proteomic and structural framework for understanding EV-mediated signaling in health and disease, providing candidate targets for therapeutic modulation of excitatory / inhibitory balance in AD.

neuroscience↗

bioRxiv2025

Xist Repeat A coordinates an assembly of SR proteins to recruit SPEN and induce gene silencing

The lncRNA Xist represents a paradigm to understand the mechanisms of RNA-mediated gene silencing in mammals, which remain largely unresolved. To induce silencing, Xist recruits the RNA-binding protein SPEN through its 5'-proximal Repeat A domain. Yet, how Repeat A recruits SPEN and how SPEN coordinates silencing remain unclear. We report that sequences in Repeat A critical for SPEN recruitment directly bind SR-rich splicing factors. SRSF1, one such factor, is required for optimal SPEN recruitment and its RS-domain recruits SPEN when tethered to Xist. SPEN and SR-protein-binding motifs promote Repeat As association with many proteins, including the m6A machinery and elongating RNA polymerase II. SPEN also represses autosomal genes where its recruitment coincides with SR-protein binding. Our results reveal an unexpectedly essential role for splicing factors in coordinating silencing by Xist and suggest that the sensing of SR-protein-rich assemblies is a general mechanism through which SPEN targets genes for repression.

genetics↗