Biology subjects

Perez-Sancho, J.

Publications and source records attributed to Perez-Sancho, J..

8 recordsLinked to original sources

bioRxiv2026

Synaptotagmin-mediated plasma membrane homeostasis is required to recruit the endocytic machinery during cold stress

Endocytosis depends on plasma membrane (PM) lipid composition, yet how plants sustain endocytic machinery recruitment during stress remains unclear. We investigated whether synaptotagmins SYT1 and SYT3 function in membrane homeostasis and endocytosis in Arabidopsis thaliana. In this work, we revealed that cold stress reversibly blocked FM4-64 internalization in syt1syt3 double mutants by displacing peripheral and core TPC subunits from the PM. Loss of SYT1 reduced brassinosteroid receptor internalization during cold stress, while double mutants showed enhanced brassinosteroid signaling. SYTs and VAP27 genes showed a condition-dependent genetic interaction in endocytosis: the syt1/vap27-1/vap27-3 triple mutant resembles vap27-1/vap27-3 under control conditions and syt1 during cold stress, suggesting overlapping contributions to endocytic regulation. Using molecular dynamics simulations of protein-membrane interactions, phosphoinositide depletion combined with increased diacylglycerol weakened TPC core membrane association. Our findings identify SYT1 and SYT3 as essential components for sustaining endocytosis during abiotic stress and support a model in which lipid homeostasis at endoplasmic reticulum-PM contact sites preserves the membrane composition required for TPC-dependent endocytosis.

plant biology↗

bioRxiv2026

Integration of SYT1 Interactomics and Dual-Localization Proteomics Links ER-PM Contacts to Lignin Deposition

Membrane contact sites (MCSs) are evolutionarily conserved intracellular nanodomains that physically bridge opposing lipid bilayers to facilitate non-vesicular communication and maintain cellular homeostasis. In plants, endoplasmic reticulum-plasma membrane (ER-PM) contact sites play fundamental roles in environmental adaptation, and are populated by specialized proteins which act as tethers such as Synaptotagmin 1 (SYT1). However, a comprehensive view of the molecular machinery governing processes at these junctions is still needed. In this work, we integrate affinity purification mass spectrometry, TurboID proximity labeling, and a dual-localization reanalysis of HyperLOPIT spatial proteomics to functionally map the protein interaction landscape of the ER-PM contact sites protein SYT1. Beyond recovering established ER-PM MCS functions, our analysis identified uncharacterized proteins as bona fide resident components of these junctions, and revealed that these nanodomains act as docking platforms that anchor the monolignol biosynthetic complex. By spatially organizing Membrane Steroid Binding Proteins and cytochrome P450 enzymes, our findings support a model where SYT1-mediated anchoring of this metabolon to ER-PM contact sites optimizes monolignol export required for stress-induced lignification. Ultimately, this proteomic framework expands the functional repertoire of ER-PM contact sites, opening new avenues to uncover hidden roles of MCSs across diverse eukaryotic systems.

molecular biology↗

bioRxiv2024

Unravelling Different Biological Roles Of Plant Synaptotagmins

Endoplasmic Reticulum-Plasma Membrane contact sites (ER-PM CS) are evolutionarily conserved membrane domains found in all eukaryotes, where the endoplasmic reticulum (ER) closely interfaces with the plasma membrane (PM). This short distance, typically 10-30 nm, is achieved in Arabidopsis through the action of tether proteins such as Synaptotagmins (SYTs). Arabidopsis comprises five SYT members (SYT1-SYT5), but whether they possess overlapping or distinct biological functions remains elusive. SYT1 is the best-characterized gene member and plays an essential role in the resistance to abiotic stress. This study reveals that while the functionally redundant SYT1 and SYT3 genes are involved in salt and cold stress resistance, SYT5 is associated with Pseudomonas syringae resistance despite evidence of in vivo interaction between SYT1 and SYT5. Structural phylogenetic analysis indicates that SYT1 and SYT5 clades emerged early in the evolution of land plants. These protein clades exhibit different structural features, rationalizing their distinct biological roles.

plant biology↗

bioRxiv2023

Plasmodesmata act as unconventional membrane contact sites regulating inter-cellular molecular exchange in plants

Membrane contact sites (MCS) are fundamental for intracellular communication, but their role in intercellular communication remains unexplored. We show that in plants, plasmodesmata communication bridges function as atypical endoplasmic reticulum (ER)-plasma membrane (PM) tubular MCS, operating at cell-cell interfaces. Similar to other MCS, ER-PM apposition is controlled by a protein-lipid tethering complex, but uniquely, this serves intercellular communication. Combining high-resolution microscopy, molecular dynamics, pharmacological and genetic approaches, we show that cell-cell trafficking is modulated through the combined action of Multiple C2 domains and transmembrane domain proteins (MCTP) 3, 4, and 6 ER-PM tethers, and phosphatidylinositol-4-phosphate (PI4P) lipid. Graded PI4P amounts regulate MCTP docking to the PM, their plasmodesmata localization and cell-cell permeability. SAC7, an ER-localized PI4P-phosphatase, regulates MCTP4 accumulation at plasmodesmata and modulates cell-cell trafficking capacity in a cell-type specific manner. Our findings expand MCSs functions in information transmission, from intracellular to intercellular cellular activities. In briefPlant intercellular communication is regulated via tubular membrane contact through PI4P binding-ER-PM tether MCTP proteins HighlightsO_LIPlasmodesmata are unconventional ER/PM tubular contact sites located at cell-cell interface C_LIO_LIPlasmodesmata operate as control valves, modulating ER-PM contacts to regulate transport C_LIO_LIMCTP3, MCTP4, MCTP6 and PI4P tethering elements act as valve regulators C_LIO_LISAC7 PI4P phosphatase controls plasmodesmata MCS in a cell-type-specific manner C_LI

plant biology↗

bioRxiv2023

Plant plasmodesmata bridges form through ER-driven incomplete cytokinesis

Diverging from conventional cell division models, plant cells undergo incomplete division to generate plasmodesmata communication bridges between daughter cells. While fundamental for plant multicellularity, the molecular events leading to bridge stabilization, as opposed to severing, remain unknown. Using electron tomography, we mapped the transition from cell plate fenestrae to plasmodesmata. We show that the ER connects daughter cells across fenestrae, and as the cell plate matures, fenestrae contract, causing the PM to mold around constricted ER tubes. The ERs presence prevents fenestrae fusion, forming plasmodesmata, while its absence results in closure. The ER-PM tethers MCTP3, 4, and 6 further stabilize nascent plasmodesmata during fenestrae contraction. Genetic deletion in Arabidopsis reduces plasmodesmata formation. Our findings reveal how plants undergo incomplete division to promote intercellular communication. One-Sentence SummaryThe ER is important for stabilizing nascent plasmodesmata, a process integral to incomplete cytokinesis in plants.

plant biology↗

bioRxiv2023

Restriction of intercellular communication is required for organ regeneration

The excision of the root tip, including the stem cell niche, triggers rapid regeneration from remnant cells in the stump. In plants, cell identity relies on positional information transported through cytoplasmatic bridges known as plasmodesmata. However, how such information is reset to allow the regeneration of lost identities is unknown. Here, we show that the movement of mobile signals is temporarily restricted near the incision site and that regeneration-induced members of the LATERAL ORGAN DOMAIN (LBD) plant-specific developmental regulators are necessary and sufficient for this restriction. Regeneration was disrupted in high-order lbd mutants but was restored by transient localized plasmodesmata closure. We propose that LBD-mediated modulation of intercellular connectivity is crucial for plant regeneration and may have widespread roles in de novo pattern formation. One Sentence SummaryPlant-specific DNA binding genes mediate a transient restriction of intercellular communication to allow root regeneration

plant biology↗

bioRxiv2020

Synaptotagmins Maintain Diacylglycerol Homeostasis at Endoplasmic Reticulum-Plasma Membrane Contact Sites during Abiotic Stress

Endoplasmic Reticulum-Plasma Membrane contact sites (ER-PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis mutants lacking the ER-PM protein tether synaptotagmin1 (SYT1) exhibit decreased plasma membrane (PM) integrity under multiple abiotic stresses such as freezing, high salt, osmotic stress and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER-PM tether that also functions in maintaining PM integrity. The ER-PM CS localization of SYT1 and SYT3 is dependent on PM phosphatidylinositol-4-phosphate and is regulated by abiotic stress. Lipidomic analysis revealed that cold stress increased the accumulation of diacylglycerol at the PM in a syt1/3 double mutant relative to WT while the levels of most glycerolipid species remain unchanged. Additionally, SYT1-GFP preferentially binds diacylglycerol in vivo with little affinity for polar glycerolipids. Our work uncovers a crucial SYT-dependent mechanism of stress adaptation counteracting the detrimental accumulation of diacylglycerol at the PM produced during episodes of abiotic stress.

molecular biology↗

bioRxiv2018

TTL proteins scaffold brassinosteroid signaling components at the plasma membrane to optimize signal transduction in plant cells

Brassinosteroids (BRs) form a group of steroidal hormones essential for plant growth, development and stress responses. Here, we report that plant-specific TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) proteins are positive regulators of BR signaling functioning as scaffold for BR signaling components in Arabidopsis. TTL3 forms a complex with all core components involved in BR signaling, including the receptor kinase BRASSINOSTEROID INSENSITIVE1 (BRI1), the transcription factor BRASSINAZOLE RESISTANT1 (BZR1) and the phosphatase BRI1-SUPPRESSOR1 (BSU1), but excluding the co-receptor BAK1. TTL3 is mainly localized in the cytoplasm, but BR treatment increases its localization at the plasma membrane, where it strengthens the association with BR signaling components. Consistent with a role in BR signaling, mutations in TTL3 and related TTL1 and TTL4 genes cause reduced BR responsiveness. We propose a mechanistic model for BR signaling, in which cytoplasmic/nuclear BR components bound to TTL proteins are recruited to the plasma membrane upon BR perception, which in turn allows the assembly of a BR signaling complex, leading to the de-phosphorylation and nuclear accumulation of the transcription factors BZR1 and BES1.

molecular biology↗