Biology subjects

Hsieh, W.-C.

Publications and source records attributed to Hsieh, W.-C..

5 recordsLinked to original sources

bioRxiv2025

Multilayer control of KaiR1D-autoreceptor function by the auxiliary protein Neto

Kainate-type glutamate receptors and their dedicated auxiliary protein Neto function at both pre- and postsynaptic sites to regulate the activity of synaptic networks. However, attributing specific synaptic functions to Neto and/or kainate receptors is challenging. Here we focus on Drosophila KaiR1D receptors, which modulate synaptic transmission at neuromuscular junction, and elucidate the role of Neto in the regulation of autoreceptor activities and neurotransmitter release. We show that Neto- limits the presynaptic accumulation and function of KaiR1D autoreceptors in vivo. Using outside-out patch recordings, we demonstrate that Neto- modulates the KaiR1D gating properties, slowing desensitization and attenuating the block by intracellular polyamines and extracellular toxins. Neto- also promotes the axonal distribution of KaiR1D, but this function is not critical for the KaiR1D-dependent regulation of synaptic transmission. Instead, Neto- increases the charge transfer and likely the KaiR1D-mediated influx of Ca2+ in the presynaptic compartment leading to increased neurotransmitter release. Our data demonstrate that Neto- provides multiple layers of modulation to KaiR1D autoreceptors to ensure proper neurotransmitter release. These findings broaden our view on how auxiliary subunits shape channel gating and subcellular distribution, suggesting that coordinated regulation of receptor function and localization represents an ancestral strategy to safeguard synaptic stability.

neuroscience↗

bioRxiv2023

Refined novel techniques for long term cryo-storage using vitrification and laser warming

Vitrification and ultra-rapid laser warming technique is an important approach for cryopreservation of animal embryos and oocytes, as well as other cells with medicinal, genetic, and agricultural value. We believe that the long term cryo-storage after vitrification and for the following laser warming has only been achieved to date using our customized device which was first attempted to be developed in our study. In the present study, we focused on developing alignment and bonding techniques for special cryo-jig which were assembling jig tool and jig holder in one piece. This newly produced customized cryo-jig was demonstrated to have significantly high laser striking accuracy of 95% and a successful rewarming rate of 62%. This study was experimentally demonstrate an refined novel device for improvement of laser striking accuracy after long term cryo-storage using vitrification and laser warming technique. In addition, the customized device described herein was successfully applied to a biological sample with over a thousand coral larvae in long term cryo-storage (The first cryo-repository for coral larvae; the results related to coral cryobanking and repositry described in this preprint will be published separately in details). We anticipate that our core findings will provide further examples of cryobanking applications that use vitrification and nano-laser warming to help a wide range of cells and tissues from diverse species.

bioengineering↗

bioRxiv2022

Yeast and Mammalian Epsins Use Different Determinants for Localization and Function: Role of Clathrin/AP2/Ubiquitin Binding Motifs and Poly-Glutamine Stretches

Epsins are endocytic adaptor proteins involved in the internalization of important membrane proteins such as EGFR and Notch ligands. Therefore, this protein family impacts critical signaling pathways and processes such as cell migration and cytokinesis and is ultimately required for embryo development in mammals and cell viability in yeast. Intriguingly, although Epsins are conserved and display similar binding determinants, the process of endocytosis in yeast and mammals exhibit some dramatic mechanistic differences. Therefore, we wondered if the function of Epsins in these organisms are similar and are similarly regulated or they also differ. Since proper and timely localization is needed for function, we determined what elements target Epsins to endocytic sites in yeast vs mammals. Specifically, using a systematic/combinatorial mutagenesis approach we produced a collection of yeast and human Epsin mutated variants that was tested for localization at endocytic sites and for function. Our results showed that the intrinsically disordered carboxy-terminus holds the major determinants (involved in binding of ubiquitin, AP2, clathrin and EH domain-containing proteins) for proper intracellular localization of different Epsin paralogs and homologs in yeast and mammals, while also having a major impact on function. Importantly, we established hierarchies of carboxy-terminal binding determinants for sustaining Epsin localization which turned to be different for human vs. yeast cells; favoring clathrin and AP2 binding in the former and recognition of cargo and EH domain-containing proteins for the latter. Further, we found evidence in both systems that yeast Epsins also use for localization regions of the protein that were until now of unknown functional relevance, i.e., glutamine-rich sequences. Interestingly, some molecular determinants within the Epsin molecule seem to have functional importance beyond its contribution to localization to endocytic sites. Based on these findings, we propose working models for Epsin function and recruitment to membranes/endocytic sites at different maturation stages.

cell biology↗

bioRxiv2020

Epigenetic therapy remodels the immune synaptic cytoskeleton to potentiate cancer susceptibility to γδ T cells

{gamma}{delta} T cells are a distinct subgroup of T cells that bridge the innate and adaptive immune systems and can attack cancer or virus-infected cells in an MHC-unrestricted manner. Despite its antitumor ability in both autologous and allogeneic settings, earlier trials of adoptive {gamma}{delta} T cell transfer in solid tumors had limited success due to limitations in cell expansion and the lack of a strategy to modulate tumor lytic interactions between {gamma}{delta} T and cancer cells. Here, we show through quantitative surface proteomics and gene enrichment analyses that DNA methyltransferase inhibitors (DNMTis) upregulate multiple surface molecules related to {gamma}{delta} T cell activation in cancer cells. DNMTi treatment of human lung cancer potentiates tumor lysis by ex vivo-expanded {gamma}{delta} T cells using a clinical-grade expansion protocol developed by our team to enrich for the V{delta}1 subset while preserving their antitumor effector functions. Mechanistically, DNMTis enhance immune synapse formation and stabilize the synaptic cleft to facilitate {gamma}{delta} T-mediated tumor lysis. Through integrated analysis of RNA-seq, DNA methylation, and ATAC-seq, we demonstrate that depletion of DNMTs induces coordinated pattern alterations of immune synaptic-cytoskeletal networks at the cancer side of the immune synapse. In addition, single-cell mass cytometry reveals enrichment of polyfunctional {gamma}{delta} T subsets by DNMTis. Combined DNMTi and adoptive {gamma}{delta} T transfer in a mouse lung cancer model offers a significant survival benefit. Consistently, the DNMTi-associated cytoskeleton signature identifies a subset of lung cancer patients with improved survival. Our results demonstrate that epigenetic mechanisms are crucial for cytoskeletal remodeling in cancer to potentiate immune attack and support a combinatorial strategy of DNMTis and {gamma}{delta} T cell-based immunotherapy in lung cancer management. One Sentence SummaryDNA methyltransferase inhibitors potentiate the killing of lung cancer by {gamma}{delta} T cells through remodeling cytoskeletal-immune synaptic networks.

cancer biology↗

bioRxiv2020

Ubiquitination and Phosphorylation are Independently Required for Epsin-Mediated Internalization of Cargo in S. cerevisiae

It is well-known that in addition to its classical role in protein turnover, ubiquitination is required for a variety of membrane protein sorting events. However, and despite substantial progress in the field, a long-standing question remains: given that all ubiquitin (Ub) units are identical, how do different elements of the sorting machinery recognize their specific cargoes? Here we provide an answer to this question as we discovered a mechanism based on the coincidence detection of lysine ubiquitination and Ser/Thr phosphorylation for the endocytic adaptor epsin to mediate the internalization of the yeast Na+ pump Ena1. Internalization of Ena1-GFP was abolished in double epsin knock-out in S. cerevisiae and was rescued by re-introducing either one of the 2 yeast epsins, Ent1 or Ent2 in an UIM (Ub Interacting Motif)-dependent manner. Further, our results indicate that ubiquitination of its C-terminal Lys1090 is needed for internalization of Ena1 and requires the arrestin-related-trafficking adaptor, Art3. We determined that in addition to ubiquitination of K1090, the presence of a Ser/Thr-rich patch (S1076TST1079) within Ena1 was also essential for its internalization. Our results suggest that this ST motif is targeted for phosphorylation by casein kinases. Nevertheless, phosphorylation of this S/T patch was not required for ubiquitination. Instead, ubiquitination of K1090 and phosphorylation of the ST motif were independently needed for epsin-mediated internalization of Ena1. We propose a model in which a dual detection mechanism is used by Ub-binding elements of the sorting machinery to differentiate among multiple Ub-cargoes.

cell biology↗