Biology subjects

Fudo, S.

Publications and source records attributed to Fudo, S..

3 recordsLinked to original sources

bioRxiv2025

Structure and functional analysis of CDNF-BiP interaction reveal a role in endoplasmic reticulum proteostasis regulation

Cerebral dopamine neurotrophic factor (CDNF) was identified for ability to rescue midbrain dopamine neurons and as endoplasmic reticulum (ER)-located protein that can be secreted. Structurally homologous to mesencephalic astrocyte-derived neurotrophic factor (MANF), CDNF has been shown to interact with ER-localized chaperone BiP. The ER plays a crucial role in protein synthesis, folding, and quality control, with BiP being a key player in maintaining protein homeostasis. CDNF is protective against ER stress and involved in regulating the unfolded protein response (UPR) signaling and interaction with BiP. Recent studies have shown that CDNF interacts with UPR sensor proteins PERK, IRE1, and ATF6, suggesting an overlap in CDNF binding with UPR sensors and BiP. In rodent models of Parkinsons disease (PD), CDNF protects and restores the function of brain dopamine neurons and was successful in PD phase 1 clinical studies. CDNF has shown therapeutic potential for several neurological diseases, including amyotrophic lateral sclerosis, and ischemic stroke. Despite extensive knowledge on CDNFs impact on cellular function and neuronal degeneration, its detailed molecular mechanism of action in the ER remains unclear. Here, we have characterized the CDNF interaction with BiP both structurally and functionally and solved the crystal structures of CDNF-BiP complexes to 1.5 [A] resolution, complemented with molecular dynamics simulations. Results show CDNFs role as an antagonist of BiP nucleotide exchange, and thus in its chaperone function, binding to the ADP-bound state. Finally, we show its effect on neuroprotection with stem cell-derived human dopamine neurons, highlighting its potential in neurodegenerative disease treatment.

biochemistry↗

bioRxiv2024

CDNF rescues human iPSCs-derived dopamine neurons through direct binding to unfolded protein response sensors PERK and IRE1α

Cerebral dopamine neurotrophic factor (CDNF) is an unconventional trophic factor that protects dopamine neurons in cellular and animal models of Parkinsons disease (PD). CDNF was safe and well tolerated in phase 1 clinical trials for PD treatment, and currently, its peptide analogue is under investigation in phase 1 clinical trials for PD. Despite prominent neuroprotective and neurorestorative activity, the receptors and exact mechanism of CDNF functioning have been obscure. Intracellularly acting CDNF exerts cytoprotection by attenuating endoplasmic reticulum (ER) stress and unfolded protein response (UPR). We demonstrated that this activity occurs through the direct binding of CDNF to ER transmembrane UPR sensors PERK and IRE1 for purified proteins and in cells. We identified CDNF mutants deficient for binding to UPR sensors. CDNF binding to PERK and IRE1 appeared to be crucial for the survival of mouse dopamine neurons in culture. Importantly for clinical translation, CDNF rescues human induced pluripotent stem cell-derived dopamine neurons and promotes their regeneration. CDNF binding to UPR sensors alleviated terminal UPR and promoted neurite outgrowth of human dopamine neurons through direct binding to PERK and IRE1. CDNF binding to BiP was dispensable for the neuroprotective and neurorestorative activity of CDNF. Therefore, CDNF, or small molecules mimicking its binding to UPR sensors and acting selectively on dopamine neurons with activated UPR, are promising drug candidates for PD treatment.

neuroscience↗

bioRxiv2022

Biophysical and functional characterization of K+-Cl- co-transporters from Drosophila melanogaster and Hydra vulgaris

The cation-chloride co-transporter (CCC) superfamily includes ion symporters, which co-transport monovalent cations and Cl-. CCCs have crucial roles in shaping signalling and neuronal connectivity in the vertebrate brain. K+-Cl- co-transporters (KCCs) are a subfamily of CCCs and carry out the symport of K+ and Cl- ions across the plasma membrane. The KCC proteins are involved in various physiological processes, such as cell volume regulation, transepithelial ion transport, synapse formation and signal transmission, and blood pressure regulation. Among KCCs, KCC2 has gained attention because of its unique and crucial functions in the central nervous system neuronal network. Loss of activity of this transporter has been associated with several neurological disorders including schizophrenia, epilepsy, and chronic pain. On the other hand, only a limited number of studies of KCCs have been published for invertebrates. Among invertebrate proteins, the Drosophila melanogaster KCC (DmKCC) has been studied most and suggested critical for neuronal transmission. Also Cnidarian Hydra vulgaris has been shown to have a functional KCC (HvKCC). Comparative analyses of these transporters with vertebrate ones and understanding functional and biophysical aspects of them as a model system can help understand the KCC mechanism of ion transport and its regulation and evolution broadly. In this study, we chose DmKCC and HvKCC as model systems and purified DmKCC and HvKCC from Sf9 insect cells and characterized their biophysical properties with differential scanning fluorimetry and light scattering techniques. We tested their functionality using a fluorescence assay and developed a method to measure recombinant KCC ion transport activity with flame photometry.

biochemistry↗