Biology subjects

Yun, J.-H.

Publications and source records attributed to Yun, J.-H..

4 recordsLinked to original sources

bioRxiv2025

Structural basis of cyclic phytocytokine recognition by the HSL3/NUT receptor

Plant receptor kinases perceive diverse peptide signals to coordinate stress responses and developmental programs. The HAESA-LIKE 3 (HSL3/NUT) receptor recognizes CTNIP/SCREW phytocytokines--disulfide-stabilized cyclic peptides that regulate immune signaling and stress adaptation. However, how HSL3 distinguishes these structurally constrained cyclic peptides from linear signaling molecules remains unknown. Here we report near-atomic resolution cryo-EM structures of HSL3 in apo and CTNIP448-70-bound states at [~]2.6 [A], using Arabidopsis CTNIP4 as a representative family member, revealing distinct mechanisms for cyclic peptide recognition. The conserved CTNIP motif occupies a negatively charged pocket in HSL3s C-terminal region through a combination of polar contacts, hydrogen bonds, salt bridges, and van der Waals interactions. The receptor employs a two-step recognition mechanism--electrostatic steering followed by motif anchoring--that enables rapid ligand capture and release, consistent with the transient nature of stress signaling. Notably, an N-glycan at Asn449 directly contacts the CTNIP4 peptide, establishing glycosylation as an active participant in ligand recognition. Structure-guided mutagenesis combined with reactive oxygen species (ROS) burst assays confirmed the functional importance of key binding interfaces. N-terminal truncation experiments revealed a minimal active fragment: CTNIP451-70 supported both rapid ROS production and sustained seedling growth inhibition, whereas the shorter CTNIP454-70 variant retained ROS activity but failed to trigger long-term seedling growth inhibition. Structure-guided coevolutionary analysis across plant lineages reveals patterns of both conserved and variable receptor-ligand interfaces, highlighting evolutionary flexibility while preserving core features of recognition. These conserved recognition principles, mediated by receptor glycosylation and evolutionary plasticity, enable specificity in peptide signaling with implications for engineering stress-resilient crops.

plant biology↗

bioRxiv2024

Discovery of a potent inhibitor that suppresses glioblastoma by dual targeting of both syntenin PDZ domains

Withdrawal StatementThe authors have withdrawn their manuscript owing to correct and validate the errors before resubmitting. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

molecular biology↗

bioRxiv2022

Cryo-EM structure of human somatostatin receptor 2 complex with its agonist somatostatin delineates the ligand binding specificity

Somatostatin is a peptide hormone regulating endocrine systems through binding to G-protein-coupled somatostatin receptors. somatostatin receptor 2 (SSTR2) is one of the human somatostatin receptors and highly implicated in cancers and neurological disorders. Here, we report the high resolution cryo-EM structure of full-length human SSTR2 bound to the agonist somatostatin (SST-14) complex with inhibitory G (Gi) proteins. Our structure shows that seven transmembrane helices form a deep pocket for ligand binding and that the highly conserved Trp-Lys motif of SST-14 positions at the bottom of the pocket. Furthermore, our sequence analysis combined with AlphaFold modeled structures of other SSTR isoforms provide how SSTR family proteins specifically interact with their cognate ligands. This work provides the first glimpse into the molecular recognition of somatostatin receptor and crucial resource to develop therapeutics targeting somatostatin receptors.

biophysics↗

bioRxiv2019

Transcriptome responses associated with carbon and energy flows under high salinity stress suggest the overflow of acetyl-CoA from glycolysis and NADPH co-factor induces high lipid accumulation and halotolerance in Chlorella sp. HS2

Previously, we isolated Chlorella sp. HS2 (referred hereupon HS2) from a local tidal rock pool and demonstrated its halotolerance and relatively high biomass productivity under different salinity conditions. To further understand acclimation responses of this alga against high salinity stress, we performed transcriptome analysis of triplicated culture samples grown in freshwater and marine conditions at both exponential and stationary growth phases. De novo assembly followed by differential expression analysis identified 5907 and 6783 differentially expressed genes (DEGs) respectively at exponential and stationary phases from a total of 52770 transcripts, and the functional enrichment of DEGs with KEGG database resulted in 1445 KEGG Orthology (KO) groups with a defined differential expression. Specifically, the transcripts involved in photosynthesis, TCA and Calvin cycles were downregulated, whereas the upregulation of DNA repair mechanisms and an ABCB subfamily of eukaryotic type ABC transporter was observed at high salinity condition. In addition, while key enzymes associated with glycolysis pathway and triacylglycerol (TAG) synthesis were determined to be upregulated from early growth phase, salinity stress seemed to reduce the carbohydrate content of harvested biomass from 45.6 dw% to 14.7 dw% and nearly triple the total lipid content from 26.0 dw% to 62.0 dw%. These results suggest that the reallocation of storage carbon toward lipids played a significant role in conferring the viability of this alga under high salinity stress, most notably by remediating high level of cellular stress partially caused by ROS generated in oxygen-evolving thylakoids.\n\nSummary StatementRedirection of storage carbon towards the synthesis of lipids played a critical role in conferring the halotolerance of a Chlorella isolate by remediating excess oxidative stress experienced in photosystems.

microbiology↗