Biology subjects

Aoki, K.

Publications and source records attributed to Aoki, K..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Live-cell fluorescence imaging and optogenetic control of PKA kinase activity in fission yeast Schizosaccharomyces pombe.

The cAMP-PKA signaling pathway plays a crucial role in sensing and responding to nutrient availability in the fission yeast Schizosaccharomyces pombe. This pathway monitors external glucose levels to control cell growth and sexual differentiation. However, the temporal dynamics of the cAMP-PKA pathway in response to external stimuli remains unclear mainly due to the lack of tools to quantitatively visualize the activity of the pathway. Here, we report the development of the kinase translocation reporter (KTR)-based biosensor spPKA-KTR1.0, which allows us to measure the dynamics of PKA activity in fission yeast cells. The spPKA-KTR1.0 is derived from the transcription factor Rst2, which translocates from the nucleus to the cytoplasm upon PKA activation. We found that spPKA-KTR1.0 translocates between the nucleus and cytoplasm in a cAMP-PKA pathway-dependent manner, indicating that the spPKA-KTR1.0 is a reliable indicator of the PKA activity in fission yeast cells. In addition, we implemented a system that simultaneously visualizes and manipulates the cAMP-PKA signaling dynamics by introducing bPAC, a photoactivatable adenylate cyclase, in combination with spPKA-KTR1.0. This system offers an opportunity for investigating the role of the signaling dynamics of the cAMP-PKA pathway in fission yeast cells with higher temporal resolution. Take AwayO_LIspPKA-KTR1.0 allows visualization of PKA activity at the single-cell level C_LIO_LILive-cell imaging reveals the transient decrease in PKA activity after M-phase C_LIO_LIOptogenetics allows simultaneous visualization and manipulation of PKA activity C_LI

cell biology↗

bioRxiv2023

ORP9-PH domain-based fluorescent reporters for visualizing phosphatidylinositol 4-phosphate dynamics in living cells

Fluorescent reporters that visualize phosphatidylinositol 4-phosphate (PI4P) in living cells are indispensable to elucidate the roles of this fundamental lipid in cell physiology. However, currently available PI4P reporters have limitations, such as Golgi-biased localization and low detection sensitivity. Here, we present a series of fluorescent PI4P reporters based on the pleckstrin homology (PH) domain of oxysterol-binding protein-related protein 9 (ORP9). We show that the green fluorescent protein AcGFP1-tagged ORP9-PH domain can be used as a fluorescent PI4P reporter to detect cellular PI4P across its wide distribution at multiple cellular locations, including the plasma membrane (PM), Golgi, endosomes, and lysosomes with high specificity and contrast. We also developed blue, red, and near-infrared fluorescent PI4P reporters suitable for multicolor fluorescence imaging experiments. Finally, we demonstrate the utility of the ORP9-PH domain-based reporter to visualize dynamic changes in the PI4P distribution and level in living cells upon synthetic ER-PM membrane contact manipulation and GPCR stimulation. This work offers a new set of genetically encoded fluorescent PI4P reporters that are practically useful for the study of PI4P biology.

cell biology↗

bioRxiv2023

Cytoplasmic fluidization triggers breaking spore dormancy in fission yeast.

The cytoplasm is a complex, crowded environment that influences myriad cellular processes including protein folding and metabolic reactions. Recent studies have suggested that changes in the biophysical properties of the cytoplasm play a key role in cellular homeostasis and adaptation. However, it still remains unclear how cells control their cytoplasmic properties in response to environmental cues. Here, we used fission yeast spores as a model system of dormant cells to elucidate the mechanisms underlying regulation of the cytoplasmic properties. By tracking fluorescent tracer particles, we found that particle mobility decreased in spores compared to vegetative cells, and rapidly increased at the onset of dormancy breaking upon glucose addition. This cytoplasmic fluidization depended on glucose sensing via the cAMP-PKA pathway. PKA activation led to trehalose degradation through trehalase Ntp1, thereby increasing particle mobility as the amount of trehalose decreased. In contrast, the rapid cytoplasmic fluidization did not require de novo protein synthesis, cytoskeletal dynamics, or cell volume increase. Furthermore, the measurement of diffusion coefficients with tracer particles of different sizes suggests that the spore cytoplasm impedes the movement of larger protein complexes (40-150 nm) such as ribosomes, while allowing free diffusion of smaller molecules ([~]3 nm) such as second messengers and signaling proteins. Our experiments have thus uncovered a series of signaling events that enable cells to quickly fluidize the cytoplasm at the onset of dormancy breaking. Significance statementCellular processes are influenced by the biophysical properties of the cytoplasm such as crowding and viscoelasticity. Although it has been suggested that cells tune the cytoplasmic properties in response to environmental changes, the molecular mechanisms remain unclear. Here, we used the dormant fission yeast spores and uncovered signaling pathways that facilitate cytoplasmic fluidization during dormancy breaking. Furthermore, we tracked the mobility of intracellular tracer particles, and found that the spore cytoplasm impedes the mobility of larger protein complexes, while allowing free diffusion of smaller molecules. These results suggest that small signaling proteins can diffuse relatively freely in the spore cytoplasm and have the ability to transmit dormancy breaking signals, while the motion of large complexes, such as ribosomes, is restricted.

cell biology↗

bioRxiv2023

Chemogenetic manipulation of endogenous proteins in fission yeast using a self-localizing ligand-induced protein translocation (SLIPT) system

Cells sense extracellular stimuli through membrane receptors and process the information through an intracellular signaling network. Protein translocation triggers intracellular signaling, and techniques such as chemically induced dimerization (CID) have been used to manipulate signaling pathways by altering the subcellular localization of signaling molecules. However, in the fission yeast Schizosaccharomyces pombe, the commonly used FKBP-FRB system has technical limitations, and therefore perturbation tools with low cytotoxicity and high temporal resolution are needed. We here applied our recently developed self-localizing ligand-induced protein translocation (SLIPT) system to S. pombe and successfully perturbed several cell cycle-related proteins. The SLIPT system utilizes self-localizing ligands to recruit binding partners to specific subcellular compartments, such as the plasma membrane or nucleus. We optimzed the self-localizing ligands to maintain long-term recruitment of target molecules to the plasma membrane. By knocking in genes encoding the binding partners for self-localizing ligands, we observed changes in the localization of several endogenous molecules and found perturbations in the cell cycle and associated phenotypes. This study demonstrates the effectiveness of the SLIPT system as a chemogenetic tool for rapid perturbation of endogenous molecules in S. pombe, providing a valuable approach for studying intracellular signaling and cell cycle regulation with improved temporal resolution.

synthetic biology↗

bioRxiv2023

Uncovering novel endolysins against methicillin-resistant Staphylococcus aureus using microbial single-cell genome sequencing

Endolysins, peptidoglycan hydrolases derived from bacteriophages (phages), are being developed as a promising alternative to conventional antibiotics. To obtain highly active endolysins, a diverse library of endolysins is vital. We here propose microbial single-cell genome sequencing as an efficient tool to discover dozens of previously unknown endolysins, owing to its culture-independent sequencing method. As a proof-of-concept, we analyzed and recovered endolysin genes within prophage regions of Staphylococcus single-amplified genomes (SAGs) in human skin microbiome samples. We constructed a library of chimeric endolysins by shuffling domains of the natural endolysins and performed high-throughput screening against Staphylococcus aureus. One of the lead endolysins, bbst1027, exhibited desirable antimicrobial properties such as rapid bactericidal activity, no detectable resistance development, and in vivo efficacy. We foresee that this endolysin discovery pipeline is in principle applicable to any bacterial target, and boost the development of novel antimicrobial agents.

microbiology↗

bioRxiv2023

Emergence of Bow-tie Architecture in Evolving Feedforward Networks

Bow-tie architecture is a layered network structure that has a narrow middle layer with multiple inputs and outputs. Such structures are widely seen in the molecular networks in cells, suggesting that a universal evolutionary mechanism underlies the emergence of bow-tie architecture. The previous theoretical studies have implemented evolutionary simulations of the feedforward network to satisfy a given input-output goal, and proposed that the bow-tie architecture emerges when the ideal input- output relation is given as a rank-deficient matrix with mutations in network link strength in a multiplicative manner. Here, we report that the bow-tie network inevitably appears when the link intensities representing molecular interactions are small at the initial condition of the evolutionary simulation, regardless of the rank of the goal matrix. Our dynamical system analysis clarifies the mechanisms underlying the emergence of the bow-tie structure. Further, we demonstrate that the increase in the input-output matrix facilitates the emergence of bow-tie architecture even when starting from strong network links. Our data suggest that bow-tie architecture emerges as a side effect of evolution rather than as a result of evolutionary adaptation. Author SummaryMany biological networks including gene regulatory networks, metabolic networks, and signaling networks, show a characteristic hierarchical structure known as the bow-tie architecture. This architecture consists of a narrow middle layer with multiple inputs and outputs. Understanding why bow-tie architecture has universally appeared through evolution may provide insight into the design principle of a network within a cell. The universality of the bow-tie structure has so far been explained by the adaptive advantages such as high evolvability and capability to classify the inputs. However, our computer simulation demonstrates that the bow-tie structure inevitably emerges even without functional advantages when the molecular interactions within the network are weak at the initial condition of the evolution. We also demonstrate that an increase in the number of inputs (i.e., receptors) and outputs (i.e., downstream genes) leads to the emergence of bow-tie architecture, even when evolution starts from a strong molecular interaction. Although many previous studies have discussed the adaptive properties of bow-tie architecture, our findings suggest that bow-tie architecture is a byproduct of evolution rather than a result of evolutionary adaptation.

systems biology↗

bioRxiv2023

Live-cell imaging provides direct evidence for a threshold in CDK activity at the G2/M transition

Cyclin-dependent kinase (CDK) plays an essential role in determining the temporal ordering of the cell cycle phases. However, despite significant progress in studying regulators of CDK, it remains elusive how they coordinately affect CDK activity at the single-cell level and how CDK controls the temporal order of cell cycle events. This could be due to the lack of tools to monitor CDK activity in living cells. Here, we elucidate the dynamics of CDK activity in fission yeast and mammalian cells by using a newly developed CDK activity biosensor, Eevee-spCDK, based on Forster Resonance Energy Transfer (FRET). Taking advantage of this system, we unravel the profile of CDK activity in vegetatively growing S. pombe cells. Thus, we detect a transient increase in S phase followed by a gradual increment during G2 phase. CDK activity then reaches its maximum in early M phase and rapidly decreases at mitotic exit. During G2 phase, CDK activity exhibits a biphasic pattern, i.e., an early slow increase and a late fast rise prior to the G2/M phase transition, as predicted from mathematical studies. Remarkably, although CDK activity does not necessarily correlate with cyclin levels, we find that it converges to the same level around mitotic onset in several mutant backgrounds, including pom1{Delta} cells and wee1 or cdc25 overexpressing cells. These data provide the first direct evidence that cells enter M phase when CDK activity reaches a high threshold, consistent with the quantitative model of cell cycle progression in fission yeast.

cell biology↗

bioRxiv2022

in vivo expression vector derived from anhydrobiotic tardigrade genome enables live imaging in Eutardigrada

Water is essential for life, but anhydrobiotic tardigrades can survive almost complete dehydration. Anhydrobiosis has been a biological enigma for more than a century with respect to how organisms sustain life without water, but the few choices of genetic toolkits available in tardigrade research have been a challenging circumstance. Here, we report the development of an in vivo expression system for tardigrades (the TardiVec system). TardiVec is based on a plasmid vector with promoters that originated from an anhydrobiotic tardigrade Ramazzottius varieornatus. It enables the introduction of GFP-fused proteins and genetically encoded indicators such as the Ca2+ indicator GCaMP into tardigrade cells; consequently, the dynamics of proteins and cells in tardigrades may be observed by fluorescence live imaging. This system is applicable for several tardigrades in the class Eutardigrada: the promoters of anhydrobiosis-related genes showed tissue-specific expression in this work. Surprisingly, promoters functioned similarly between multiple species, even for species with different modes of expression of anhydrobiosis-related genes, such as Hypsibius exemplaris, in which these genes are highly induced upon facing desiccation, and Thulinius ruffoi, which lacks anhydrobiotic capability. These results suggest that the highly dynamic expression changes in desiccation-induced species are regulated in trans. Tissue-specific expression of tardigrade-unique unstructured proteins also suggests differing anhydrobiosis machinery depending on the cell types. We believe that TardiVec opens up various experimental possibilities in tardigrade research, especially to explore anhydrobiosis mechanisms.

molecular biology↗

bioRxiv2022

Novel monoclonal antibodies showing broad neutralizing activity for SARS-CoV-2 variants including Omicrons BA.5 and BA.2.75

We identified novel neutralizing monoclonal antibodies against SARS-CoV-2 variants (including Omicron) from individuals received two doses of mRNA vaccination after they had been infected with wildtype. We named them MO1, MO2 and MO3. MO1 shows high neutralizing activity against authentic variants: D614G, Delta, BA.1, BA.1.1, BA.2, and BA.2.75 and BA.5. Our findings confirm that the wildtype-derived vaccination can induce neutralizing antibodies that recognize the epitopes conserved among the SARS-CoV-2 variants (including BA.5 and BA.2.75). The monoclonal antibodies obtained herein could serve as novel prophylaxis and therapeutics against not only current SARS-CoV-2 viruses but also future variants that may arise.

microbiology↗

bioRxiv2022

Optogenetic control of cell signaling with red/far-red light-responsive optogenetic tools in Caenorhabditis elegans.

Optogenetic techniques have been intensively applied to the nematode Caenorhabditis elegans to investigate its neural functions. However, as most of these optogenetics are responsive to blue light and the animals exhibits avoidance behavior to blue light, the application of optogenetic tools responsive to longer wavelength light has been eagerly anticipated. In this study, we report the implementation in C. elegans of a phytochrome-based optogenetic tool that responds to red/near-infrared light and manipulates cell signaling. We first introduced the SynPCB system, which enabled us to synthesize phycocyanobilin (PCB), a chromophore for phytochrome, and confirmed the biosynthesis of PCB in neurons, muscles, and intestinal cells. We further confirmed that the amount of PCBs synthesized by the SynPCB system was sufficient for photoswitching of phytochrome B (PhyB)-phytochrome interacting factor 3 (PIF3). In addition, optogenetic elevation of intracellular Ca2+ levels in intestinal cells induced a defecation motor program. These SynPCB system and phytochrome-based optogenetic techniques would be of great value in elucidating the molecular mechanisms underlying C. elegans behaviors.

synthetic biology↗

bioRxiv2022

Comprehensive analysis of platelet glycoprotein Ibα glycosylation.

BackgroundPlatelet glycoprotein (GP) Ib is the major ligand-binding subunit of the GPIb-IX-V complex that binds von Willebrand Factor (VWF). GPIb is heavily glycosylated, and its glycans have been proposed to play key roles in platelet clearance, VWF binding, and as target antigens in immune thrombocytopenia syndromes. Despite its importance in platelet biology, the glycosylation profile of GPIb is not well characterized. ObjectivesThe aim of this study was to comprehensively analyze GPIb amino acid sites of glycosylation (glycosites) and glycan structures. MethodsGPIb ectodomain that was recombinantly expressed or that was purified from human platelets was analyzed by Western blot, mass spectrometry (MS) glycomics, and MS glycoproteomics to define glycosites and the structures of the attached glycans. ResultsWe identified a diverse repertoire of N- and O-glycans, including sialoglycans, Tn antigen, T antigen, and ABH blood group antigens. In the analysis of the recombinant protein, we identified 62 unique O-glycosites. In the analysis of the endogenous protein purified from platelets, we identified at least 48 unique O-glycosites and 1 N-glycosite. The GPIb mucin domain is densely O-glycosylated. Glycosites are also located within the macroglycopeptide domain and mechanosensory domain (MSD). ConclusionsThis comprehensive analysis of GPIb glycosylation lays the foundation for further studies to determine the functional and structural roles of GPIb glycans. Essentials- Glycosylation of glycoprotein Ib (GPIb) is important for platelet function. - We report a comprehensive and site-specific analysis of human GPIb glycosylation. - GPIb carries sialoglycans, Tn antigen, T antigen, and ABO blood group (ABH) antigens. - We experimentally determined 48 O-glycosites and 1 N-glycosite by mass spectrometry.

biochemistry↗

bioRxiv2022

Optimal inference of molecular interactions in live FRET imaging

Intensity-based live-cell fluorescence resonance energy transfer (FRET) imaging converts otherwise unobservable molecular interactions inside cells into fluorescence time-series signals. However, inferring the degree of molecular interactions from these observables is challenging, due to experimental complications such as spectral crosstalk, photobleaching, and measurement noise. Conventional methods solve this inverse problem through algebraic manipulations of the observables, but such manipulations inevitably accumulate measurement noise, limiting the scope of FRET analysis. Here, we introduce a Bayesian inference framework, B-FRET, which estimates molecular interactions from FRET data in a statistically optimal manner. B-FRET requires no additional measurements beyond those routinely conducted in standard 3-cube FRET imaging methods, and yet, by using the information contained in the data more efficiently, dramatically improves the signal-to-noise ratio (SNR). We validate B-FRET using simulated data, and then apply it to FRET data measured from single bacterial cells, a system with notoriously low SNR, to reveal signaling dynamics that are otherwise hidden in noise.

biophysics↗

bioRxiv2022

Glia-neuron coupling via a bipartite sialylation pathway promotes neural transmission and stress tolerance in Drosophila

Modification by sialylated glycans can affect protein functions, underlying mechanisms that control animal development and physiology. Sialylation relies on a dedicated pathway involving evolutionarily conserved enzymes, including CMP-sialic acid synthetase (CSAS) and sialyltransferase (SiaT) that mediate the activation of sialic acid and its transfer onto glycan termini, respectively. In Drosophila, CSAS and DSiaT genes function in the nervous system, affecting neural transmission and excitability. We found that these genes function in different cells: the function of CSAS is restricted to glia, while DSiaT functions in neurons. This partition of the sialylation pathway allows for regulation of neural functions via a glia-mediated control of neural sialylation. The sialylation genes were shown to be required for tolerance to heat and oxidative stress and for maintenance of the normal level of voltage-gated sodium channels. Our results uncovered a unique bipartite sialylation pathway that mediates glia-neuron coupling and regulates neural excitability and stress tolerance. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/486211v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@15b8de3org.highwire.dtl.DTLVardef@1c037e8org.highwire.dtl.DTLVardef@9674bborg.highwire.dtl.DTLVardef@1c9c010_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2021

Identification of bacterial drug-resistant cells by the convolutional neural network in transmission electron microscope images

The emergence of bacteria that are resistant to antibiotics is common in areas where antibiotics are used widely. The current standard procedure for detecting bacterial drug resistance is based on bacterial growth under antibiotic treatments. Here we describe the morphological changes in enoxacin-resistant Escherichia coli cells and the computational method used to identify these resistant cells in transmission electron microscopy (TEM) images without using antibiotics. Our approach was to create patches from TEM images of enoxacin-sensitive and enoxacin-resistant E. coli strains, use a convolutional neural network for patch classification, and identify the strains on the basis of the classification results. The proposed method was highly accurate in classifying cells, achieving an accuracy rate of 0.94. Using a gradient-weighted class activation mapping to visualize the region of interest, enoxacin-resistant and enoxacin-sensitive cells were characterized by comparing differences in the envelope. Moreover, Pearsons correlation coefficients suggested that four genes, including lpp, the gene encoding the major outer membrane lipoprotein, were strongly associated with the image features of enoxacin-resistant cells.

systems biology↗

bioRxiv2021

Hyperconcentrated Mucus Unifies Submucosal Gland and Superficial Airway Dysfunction in Cystic Fibrosis

Cystic fibrosis (CF) is characterized by abnormal transepithelial ion transport. However, a description of CF lung disease pathophysiology unifying superficial epithelial and submucosal gland (SMG) dysfunctions has remained elusive. We hypothesized that biophysical abnormalities associated with CF mucus hyperconcentration provide a unifying mechanism. Studies of the anion secretion-inhibited pig airway CF model revealed elevated SMG mucus concentrations, osmotic pressures, and SMG mucus accumulation. Human airway studies revealed hyperconcentrated CF SMG mucus with raised osmotic pressures and cohesive forces predicted to limit SMG mucus secretion/release. Utilizing proline-rich protein 4 (PRR4) as a biomarker of SMG secretion, proteomics analyses of CF sputum revealed markedly lower PRR4 levels compared to healthy and bronchiectasis controls, consistent with a failure of CF SMGs to secrete mucus onto airway surfaces. Raised mucus osmotic/cohesive forces, reflecting mucus hyperconcentration, provide a unifying mechanism that describes disease-initiating mucus accumulation on airway surfaces and within SMGs of the CF lung.

pathology↗

bioRxiv2021

Multiplexed fluorescence imaging of GPCR downstream signaling dynamics at the single-cell level.

G-protein-coupled receptors (GPCRs) play an important role in sensing various extracellular stimuli, such as neurotransmitters, hormones, and tastants, and transducing the input information into the cell. While the human genome encodes more than 800 GPCR genes, only four G-proteins (Gs, Gi/o, Gq/11, and G12/13) are known to couple with GPCRs. It remains unclear how such divergent GPCR information is translated into the downstream G-protein signaling dynamics. To answer this question, we report a live-cell fluorescence imaging system for monitoring GPCR downstream signaling dynamics at the single-cell level. Genetically encoded biosensors for cAMP, Ca2+, RhoA, and ERK were selected as markers for GPCR downstream signaling, and were stably expressed in HeLa cells. GPCR was further transiently overexpressed in the cells. As a proof-of-concept, we visualized GPCR signaling dynamics of 5 dopamine receptors and 12 serotonin receptors, and found heterogeneity between GPCRs and between cells. Even when the same G proteins were known to be coupled, the patterns of dynamics in GPCR downstream signaling, including the signal strength and duration, were substantially distinct among GPCRs. These results suggest the importance of dynamical encoding in GPCR signaling.

cell biology↗

bioRxiv2021

In vivo study on the healing of bone defect treated with non-thermal atmospheric pressure gas discharge plasma

Medical treatment using non-thermal atmospheric pressure gas discharge plasma is rapidly gaining recognition. Gas discharge plasma is thought to generate highly reactive species in an ambient atmosphere, which could be exposed to biological targets (e.g., cells and tissues). If plasma-generated reactive species could stimulate bone regeneration, gas discharge plasma could provide a new treatment opportunity in regenerative medicine. We investigated the impact of plasma on bone regeneration using a large bone defect in model rabbits and simple atmospheric pressure plasma (helium microplasma jet). We tracked the recovery progress of the large bone defects by X-ray imaging over eight weeks. The X-ray results showed a clear difference in the filling of the large bone defect among groups with different plasma treatment times, whereas filling was not substantial in the untreated control group. According to the results of micro-computed tomography analysis at eight weeks, the most successful bone regeneration was achieved using a plasma treatment time of 10 min, wherein the new bone volume was 1.51 times larger than that in the control group. Overall, these results suggest that non-thermal atmospheric pressure gas discharge plasma is promising for fracture treatment.

pathology↗

bioRxiv2021

Neural-specific alterations in glycosphingolipid biosynthesis and cell signaling associated with two human ganglioside GM3 Synthase Deficiency variants

GM3 Synthase Deficiency (GM3SD) is a neurodevelopmental disorder resulting from pathogenic variants in the ST3GAL5 gene, which encodes GM3 synthase, a glycosphingolipid (GSL)-specific sialyltransferase. This enzyme adds a single 3-linked sialic acid to the terminal galactose of lactosylceramide (LacCer) to produce the monosialylated ganglioside GM3. In turn, GM3 is extended by other glycosyltransferases to generate nearly all the complex gangliosides enriched in neural tissue. Pathogenic mechanisms that account for neural phenotypes associated with GM3SD are not known. To explore how loss of GM3 impacts neural-specific glycolipid glycosylation and cell signaling, GM3SD patient fibroblasts bearing one of two different ST3GAL5 variants were reprogrammed to induced pluripotent stem cells (iPSCs) and then differentiated to neural crest cells (NCCs). GM3 and GM3-derived gangliosides were undetectable in iPSCs and NCCs from both variants, while LacCer precursor levels were elevated compared to wildtype (WT). NCCs of both variants synthesized elevated levels of neutral lacto- and globo-series, as well as minor alternatively sialylated, GSLs compared to WT. Shifts in ceramide profiles associated with iPSC and NCC GSLs were also detected in GM3SD variants. Altered GSL profiles in the GM3SD cells were accompanied by dynamic changes in the cell surface proteome, protein O-GlcNAcylation, and receptor tyrosine kinase abundance. GM3SD cells also exhibited increased apoptosis and sensitivity to erlotnib, an inhibitor of epidermal growth factor receptor signaling. Pharmacologic inhibition of O-GlcNAcase increased protein O-GlcNAcylation and significantly rescued baseline and erlotnib-induced apoptosis. Collectively, these findings indicate broad effects on cell signaling during differentiation of GM3SD patient-derived iPSCs to NCCs. Thus, human GM3SD cells provide a novel platform to investigate structure/function relationships that connect GSL diversity to cell signaling, cell survival, and neural differentiation.

neuroscience↗