Tal Laviv @lavivtal.bsky.social · 26/12/2025We are further perusing shing this approach in many different directions- different cell types in the brain, and completely different model systems to monitor autophagy and pH using this general approach so hope much more to come in the future. 010
Tal Laviv @lavivtal.bsky.social · 26/12/2025All of this would not be possible without the support and funding from the Chan Zuckerberg Initiative that contributed to this work at a critical step and really allowed us to pursue grand challenges. 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025This work was possible due to critical contribution from Ben Scholl that helped us analyze vesicle movement in vivo, which was not an easy challenge. Brock Grill and Muriel Dubois were key driving forces to implement this sensor in C elegans 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025Much more in the paper! Including some evidence that dendritic autophagy dynamics is experience dependent! This work was a true team effort led by brilliant student Maya Maman, with critical help from lab members. 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025The most striking feature is that the sensitivity of this approach allows to track autophagic vesicle transport in vivo for the first time! We found that distal dendritic segments showed elevated speed of autophagic vesicles, while proximal dendrites were more stable. 121
Tal Laviv @lavivtal.bsky.social · 26/12/2025Using 2pFLIM, we were able to gain access to autophagic levels in cell bodies, dendrites and axons. One of the striking things we found was that autophagy levels are vastly different across different dendritic compartments, which were previously unknown. 120
Tal Laviv @lavivtal.bsky.social · 26/12/2025We benchmarked this approach in a number of models, cell lines, neuronal cultures and even C. elegans. Most importantly, this robust approach now allows us to monitor autophagy levels in the living mouse brain! 120
Tal Laviv @lavivtal.bsky.social · 26/12/2025We used fluorescence lifetime (FLIM) to solve this problem! By engineering a new FRET pair, we standardize pH-based monitoring in cells. We used a recently discovered pH insensitive FRET donor, named TOLLES, which showed high resilience and its lifetime was pH independent. 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025This approach has been instrumental studying autophagy in neuronal cultures or small organisms. However, monitoring autophagy in mammalian brains remains challenging, since it is difficult to detect small changes in fluorescence intensity, in particular in acidic compartments. 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025This approach allows to use the properties of GFP and RFP to determine the state of autophagy- since GFP is easily degraded in acidic compartments, the transition from autophagosomes to autolysosome is associated with GFP degradation. 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025While numerus approaches were developed to measure autophagy, tracking autophagy in living cells relied primarily on fluorescent intensity. The principle of this approach relies on tagging LC3, an essential component of autophagy vesicles with a GFP-RFP fusion. 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025We know that autophagy is critical for normal brain development- its disruption in early stages leads to brain dysfunction and neurodegeneration. Autophagy dysfunction is indeed associated with many human pathologies- in development and also during neurodegeneration. 110
Tal Laviv @lavivtal.bsky.social · 26/12/2025Autophagy is a central mechanism which allows cells to maintain homeostasis, by allowing efficient degradation of proteins, lipids and organelles. Generally, autophagy is triggered in response to various stress signals, which indicate reduction in energy levels. 120
Tal Laviv @lavivtal.bsky.social · 26/12/2025I am excited to share our new paper, where we developed and used a new approach that allows us to dynamically monitor autophagy in the intact mouse brain! biorxiv.org/cgi/content/...biorxiv.orgFluorescence lifetime-based biosensor for monitoring compartmentalized autophagy dynamics in the intact mammalian brainSynaptic architecture underlies neuronal computation, with autophagy serving as a key regulator of synaptic plasticity, function and local metabolism. Yet, autophagy dynamics and regulation within int... 1157
Tal Laviv @lavivtal.bsky.social · 20/02/2025This project was spearheaded by a Tomar Kagan, a talented PhD student in my lab. special thanks for @ritastrack.bsky.social and nature methods team for their professional and supportive process to improve the paper to its present form, it was a real pleasure to work with them. 141
Tal Laviv @lavivtal.bsky.social · 20/02/2025This highlights the need to explore PTEN signaling in a cell-specific manner, and to further explore the original findings and associate PTEN signaling during early brain development! I would like to thank all the collaborators that helped us in this project, and my lab members for their hard work. 130
Tal Laviv @lavivtal.bsky.social · 20/02/2025I will end with our favorite and perhaps most exciting finding. We used a red shifted PTEN sensor, and combined it to a dual color PTEN imaging in excitatory and Inhibitory cells. We found differential experience dependent changes in E and I cells! 120
Tal Laviv @lavivtal.bsky.social · 20/02/2025But how about interfering with PTEN function? For this we used a LOF mutation previously identified in a PTEN screen. This manipulation still maintains flexible conformational change of PTEN but completely mitigates the effect on downstream signaling and cellular structure and function. 120
Tal Laviv @lavivtal.bsky.social · 20/02/2025Luckily for us, nature already made PTEN an ideal substrate- since it undergoes a conformational transition upon activation, from closed to open state. We use this to tag PTEN with FP and dynamically monitor PTEN conformation a proxy for its activity state. 120
Tal Laviv @lavivtal.bsky.social · 20/02/2025Despite this important role, there were no tools to directly measure PTEN activity, in particular in single cell resolution and in intact neuronal circuits. We engineered a FRET based PTEN sensor, which is optimized for 2pFLIM. 130
Tal Laviv @lavivtal.bsky.social · 20/02/2025Numerus human cancers are associate with PTEN mutations. In the brain, mutations in PTEN lead to epilepsy, autism and macrocephaly. Work in mouse models showed that both an increase and a decrease in PTEN levels has detrimental neuronal consequences. 120
Tal Laviv @lavivtal.bsky.social · 20/02/2025 We have developed a biosensor to monitor PTEN activity in living cells, tissue and even whole organisms!! PTEN is a vital phosphatase found in every cell, and acts as an inhibitor of cellular tropism, essential to protect cells from excessive growth and proliferation. 120
Tal Laviv @lavivtal.bsky.social · 20/02/2025I started my lab more then 4 years ago, and we have endured some very challenging times ever since.…I am very excited to share the first paper from my lab, published now in @naturemethods.bsky.social www.nature.com/articles/s41...nature.comGenetically encoded biosensor for fluorescence lifetime imaging of PTEN dynamics in the intact brain - Nature MethodsA first-in-class fluorescence lifetime-based FRET sensor for phosphatase and tensin homolog (PTEN) enables the dynamic monitoring of PTEN activity in cultured cells and in vivo with high spatiotempora... 1013831
Reposted by Tal LavivInna Slutsky @innaslutsky.bsky.social · 15/01/2025Yesterday, we held the 2024 Sieratzki Prizes Ceremony at the ISFN meeting in Eilat. We are so proud of our 2024 winners: @yoavlivneh.bsky.social , Arseny Finkelstein, David Omer, @lavivtal.bsky.social, and Inbal Ben-Ami Bartal! 081
Reposted by Tal LavivEric Topol @erictopol.bsky.social · 19/12/2024How to improve memory and cognitive function in aged mice Fix the mitochondrial EC (excitation-coupling) @science.org representing a new potential path for replenishing neuronal energy reserves to counter brain aging www.science.org/doi/10.1126/... 524141
Tal Laviv @lavivtal.bsky.social · 20/12/2024Beautiful work by my the lab of Huan Ma, which I had the pleasure to contribute to. A fascinating link between neuronal activity, and transcription-excitation coupling in mitochodria to brain function and ageing www.science.org/doi/10.1126/...science.orgBoosting neuronal activity-driven mitochondrial DNA transcription improves cognition in aged miceDeciphering the complex interplay between neuronal activity and mitochondrial function is pivotal in understanding brain aging, a multifaceted process marked by declines in synaptic function and mitoc... 040
Tal Laviv @lavivtal.bsky.social · 16/11/2024Hello there! My first try here: Sharing an in vivo image of a beautiful dendrite with a GFP knock-in to endogenous CaMKIIa 0274
Reposted by Tal LavivMichael Ward @michael-e-ward.bsky.social · 15/11/2024Pathogenic proteotoxicity of cryptic splicing is alleviated by ubiquitination and ER-phagy www.science.org/doi/10.1126/...science.orgPathogenic proteotoxicity of cryptic splicing is alleviated by ubiquitination and ER-phagyRNA splicing enables the functional adaptation of cells to changing contexts. Impaired splicing has been associated with diseases, including retinitis pigmentosa, but the underlying molecular mechanis... 093
Reposted by Tal LavivDanielle Beckman @daniellebeckman.bsky.social · 14/11/2024I'm very happy with how this image turned out and can't even wait for #FluorescenceFriday! I'm trying to detect Tau protein phosphorylation before forming full fibrillary tangles in #Alzheimer disease. Healthy neurons: (🟠NeuN), Dying neurons: pTau ( 🟣422), (🔵AT8). More info in the Alt tex! 🧠🔬 618829
