Biology subjects

Luetzkendorf, J.

Publications and source records attributed to Luetzkendorf, J..

5 recordsLinked to original sources

bioRxiv2026

Targeting IGF2BP1 Creates a Mitotic Vulnerability in Colorectal Carcinoma

Background Mitotic dysregulation is a common feature of colorectal cancer (CRC), yet the contribution of post-transcriptional mechanisms remain incompletely understood. We investigated how the oncofetal RNA-binding protein IGF2BP1 supports mitotic integrity and exposes therapeutic vulnerabilities in CRC. Methods We integrated patient cohort analyses with genetic and pharmacological perturbation of IGF2BP1, transcriptomics, proteomics, RNA-binding assays and functional studies. Xenografts assessed tumor formation, while BTYNB-paclitaxel responses were examined in CRC cell lines and patient-derived organoids. Results IGF2BP1 expression was elevated in CRC, increased with tumor stage, and associated with poor survival and proliferative gene signatures. Genetic depletion or pharmacological inhibition of IGF2BP1 impaired cell viability, induced mitotic abnormalities, and promoted apoptosis, whereas its re-expression enhanced tumor formation in vivo. Integrated molecular analyses identified the chromosomal passenger complex (CPC) as a previously unrecognized downstream target of IGF2BP1. IGF2BP1 bound transcripts encoding CPC components and its depletion consistently reduced their expression across multiple cancer cell models. BTYNB disrupted IGF2BP1 association with INCENP, CDCA8, and BIRC5 transcripts and accelerated INCENP mRNA decay. Functionally, INCENP depletion recapitulated the mitotic defects and impaired viability observed upon IGF2BP1 inhibition. Exploiting this mitotic vulnerability, BTYNB synergized with paclitaxel in CRC cell lines and across four independent IGF2BP1-positive patient-derived organoid models. Conclusions Our findings uncover an IGF2BP1-dependent post-transcriptional regulatory mechanism sustaining CPC expression and mitotic integrity in CRC. Targeting this mechanism exposes a therapeutically exploitable mitotic vulnerability and provides a rationale for combining IGF2BP1 inhibition with microtubule-targeting agents.

cancer biology↗

bioRxiv2025

Autophagy-driven Presynaptic Reorganization as a Molecular Signature of Brain Resilience.

Neural circuits must remain functionally stable while responding flexibly to changing demands, stressors, and aging-related decline. While this balance is thought to be maintained through plasticity programs that integrate molecular, metabolic, and activity-dependent signals to reconfigure synapses structurally and functionally, direct mechanistic models of how such adaptations are orchestrated remain scarce. Here, we show that targeted impairment of autophagy in the Drosophila mushroom body (MB), a key sleep-regulatory and integrative center in the fly brain, triggers a brain-wide remodeling at presynaptic active zones (AZ). Quantitative proteomics revealed a specific upregulation of AZ scaffold proteins (including BRP, RIM, and Unc13A), accompanied by reduced levels of calcium channel subunits and increased Shaker-type potassium channels. These changes occurred largely independent of transcription and highlight a coordinated, excitability-tuning response centered on the AZ. Behaviorally, MB-specific autophagy impairment increased sleep and modestly extended lifespan. These adaptations resembled a previously described resilience program termed PreScale, which promotes restorative sleep homeostasis in response to sleep deprivation and early, still reversible brain aging. Conversely, overexpression of Atg5 in the MB delayed the onset of PreScale. Notably, autophagic disruption confined to MB neurons also caused widespread, non-cell autonomous accumulation of Ref(2)P and ATG8a-positive aggregates across the brain, revealing systemic propagation of proteostatic stress. Together, our findings identify MB autophagy as a key regulator of synaptic architecture and sleep-associated resilience. Such early acting programs may actively preserve circuit function and behavioral output by regulating synaptic plasticity, and define a genetically tractable model for how local stress signals can orchestrate brain-wide adaptation via post-transcriptional synaptic reprogramming.

neuroscience↗

bioRxiv2025

Non-cell autonomous control of presynaptic remodeling by the hypothalamic autophagy/NPY axis

Macroautophagy/autophagy, a critical cellular degradation pathway essential for maintaining neuronal proteostasis, declines with age and has been increasingly implicated in the regulation of synaptic integrity and circuit resilience. Neuropeptide Y (NPY), the most abundantly expressed neuropeptide in the mammalian brain, has emerged as a key modulator of both autophagy and aging-related processes. In Drosophila, the NPY-family peptide short Neuropeptide F (sNPF) has been shown to causally influence aging-associated changes in synaptic architecture and function, particularly at the presynaptic active zone (AZ), via non-cell autonomous mechanisms. Extending this concept to mammals, we investigated whether NPY and autophagy interact within NPY-secreting neurons to regulate age-related AZ remodeling. Our results indicate that hypothalamic NPY/AgRP neurons may exert geroprotective effects through the release of NPY and potentially other signaling molecules, thereby influencing both metabolic homeostasis and brain-wide synaptic function. These data suggest a conserved role for autophagy in maintaining presynaptic organization and resilience during aging.

neuroscience↗

bioRxiv2024

Identification and characterization of a synaptic active zone assembly protein

At presynaptic active zones (AZs), scaffold proteins play a crucial role in coordinating synaptic vesicle (SV) release and forming intricate nanoarchitectures essential for synaptic function. Despite their suspected importance, factors governing the assembly of nanoscale AZ scaffolds have remained elusive. Here, we identify "Blobby" as a novel regulator of AZ nanopatterning, localized within the AZ scaffold. Genetic loss of the extended Blobby protein led to aberrant accumulation of AZ scaffold proteins ("blobs") and disrupted the nanoscale architecture of the AZ scaffold, resulting in a significant reduction in the packing density of voltage-gated Ca2+ channels at AZs, as observed through intravital single-molecule imaging. This disruption correlated with decreased evoked synaptic currents and SV release probability. Our findings suggest that Blobby plays a crucial role in switching the AZ scaffold into a state which allows to fine-tune the dynamic nanopatterning of Ca2+ channels to maintain proper release.

neuroscience↗

bioRxiv2020

Presynaptic precursor vesicles originate from the trans-Golgi network, promoted by the small GTPase RAB2

Reliable delivery of presynaptic material, including active zone and synaptic vesicle proteins from neuronal somata to synaptic terminals is prerequisite for faithful synaptogenesis and neurotransmission. However, molecular mechanisms controlling the somatic assembly of presynaptic precursors remain insufficiently understood. Here we show that in mutants of the small GTPase RAB2 active zone and synaptic vesicle proteins accumulated in the neuronal somata at the trans-Golgi network and were consequently depleted at synaptic terminals, provoking neurotransmission deficits. The ectopic presynaptic material accumulations consisted of heterogeneous vesicles and short tubules of 40x60 nm and segregated in subfractions either positive for active zone proteins or co-positive for synaptic vesicle proteins and LAMP1, a lysosomal membrane protein. Genetically, rab2 behaved epistatic over arl8, a lysosomal adaptor controlling axonal export of precursors. Collectively, we here identified a Golgi-associated assembly sequence in presynaptic precursor vesicle biogenesis controlled by RAB2 dependent membrane remodelling and protein sorting at the trans-Golgi.

neuroscience↗