Biology subjects

Deane-Alder, K.

Publications and source records attributed to Deane-Alder, K..

3 recordsLinked to original sources

bioRxiv2026

Redox-dependent dimerization of PolDIP2 and a conserved ApaG-domain motif required for CHCHD2 interaction

PolDIP2 is a multifunctional mitochondrial protein implicated in redox regulation, mitochondrial proteostasis, and diverse mtDNA-associated processes, yet the principles underlying its regulation remain unclear. Crystallographic analysis revealed that PolDIP2 forms a redox-dependent disulfide-linked homodimer via a conserved Cys143 residue within its N-terminal YccV-like domain, and cellular and in vitro assays confirmed that this residue is essential for dimer formation. Oxidative stress enhanced dimerization of endogenous and ectopically expressed PolDIP2, and dimers were detected exclusively within mitochondria, requiring proper mitochondrial import. WT and C143A PolDIP2 overexpression produced similarly modest effects on mtDNA replication in cells, suggesting that dimerization has limited impact on mtDNA-associated processes. Proteomic analysis and biochemical validation identified both previously known and not yet characterized mitochondrial interactors of PolDIP2, and highlighted CHCHD2 as a specific binding partner. A conserved glycine-rich motif in the C-terminal ApaG/DUF525-like domain proved essential for this interaction, and disruption of the motif enhanced Cys143-dependent dimerization while abolishing CHCHD2 association, which preferentially occurs with monomeric PolDIP2. These findings define redox-controlled dimerization and a conserved ApaG-domain motif as key structural features shaping PolDIP2s interaction state within mitochondria and provide a basis for exploring its roles in redox-sensitive mitochondrial pathways.

cell biology↗

bioRxiv2025

Pili are essential for conjugation also in many Gram-positive bacteria

Type IV secretion systems (T4SS) enable the spread of antibiotic resistance and other virulence factors. In Gram-positive bacteria, T4SSs have long been thought to lack VirB2-like proteins that form conjugative pili and instead rely on adhesins for cell-cell contacts. Yet, it has remained unclear how subsequent DNA transfer (conjugation) is physically mediated. Here we identify a VirB2-like protein, PrgFB2, from the clinically isolated conjugative plasmid pCF10 in Enteroccocus faecalis and show that it is essential for conjugation. Structural modeling confidently predicts a pilus-like assembly for PrgFB2. We validate this prediction through mutagenesis, conjugation assays, and targeted chemical labeling. By combining various machine learning bioinformatic techniques, we analysed >1000 Gram-positive conjugative plasmids from diverse species, including major pathogens, and identified pili forming VirB2-like proteins in almost all of them. Our findings overturn the prevailing view that Gram-positive T4SSs lack pili. This discovery provides a new framework for understanding horizontal gene transfer and highlights critical targets for combating antimicrobial resistance and virulence in Gram-positive bacteria.

microbiology↗

bioRxiv2024

In vivo functional profiling and structural characterisation of the human Glp1r A316T variant

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are effective therapies for type 2 diabetes (T2D) and obesity, yet patient responses are variable. Variation in the human Glp1r gene might be directly linked to therapeutic responses. A naturally occurring missense variant, A316T, protects against T2D and cardiovascular disease. Here, we have generated and characterised a human Glp1r A316T mouse model. Human Glp1rA316T/A316T mice displayed lower fasting blood glucose versus wildtype littermates, even under metabolic stress, and exhibited alterations in islet cytoarchitecture and /{beta}-cell identity under a high-fat, high-sucrose diet. This was however associated with blunted responses to GLP-1RAs in vivo. Further investigations in rodent and human {beta}-cell models demonstrated that human Glp1r A316T exhibits characteristics of constitutive activation but dampened GLP-1RA responses. Results are further supported by cryo-EM analyses and molecular dynamics simulations of GLP-1R A316T structure, collectively demonstrating that the A316T variant governs basal GLP-1R activity and pharmacological responses to GLP-1R-targeting therapies. TeaserThe Glp1r A316T missense variant displays improved glucose tolerance but impaired pharmacological incretin responses in vivo.

cell biology↗