Biology subjects

Olerinyova, A.

Publications and source records attributed to Olerinyova, A..

5 recordsLinked to original sources

bioRxiv2025

A structural and regulatory framework for Atg9-containing vesicle formation and their Atg1-dependent remodelling during autophagy initiation

Autophagy is a complex intracellular degradation pathway that depends on the coordinated interplay between the core autophagy machinery and diverse membrane sources to drive the de novo formation of double-membrane vesicles, known as autophagosomes. Golgi-derived Atg9-containing vesicles are essential for this process, delivering membranes to the pre-autophagosomal structure (PAS). These vesicles contain the transmembrane proteins Atg9 and Atg27 and the peripheral membrane protein Atg23; however, the nature, function, and regulation of their interactions remain poorly understood. Here, we systematically dissect the molecular interactions between Atg9, Atg23 and Atg27, and uncover their regulation in space and time. The bipartite binding mode by which Atg23 engages Atg9 provides a structural model for how Atg23 promotes vesicle budding. Furthermore, Atg1-dependent phosphorylation of Atg9 remodels its interactions with Atg23 and Atg27 at the PAS to support autophagy initiation. Together, these findings establish a molecular and regulatory framework for the earliest steps of autophagy.

biochemistry↗

bioRxiv2024

Molecular determinants of protein pathogenicity at the single-aggregate level

Determining the structure-function relationships of protein aggregates is a fundamental challenge in biology. These aggregates, whether formed in vitro, within cells, or in living organisms, present significant heterogeneity in their molecular features such as size, structure, and composition, making it difficult to determine how their structure influences their functions. Interpreting how these molecular features translate into functional roles is crucial for understanding cellular homeostasis and the pathogenesis of various debilitating diseases like Alzheimers and Parkinsons. In this study, we introduce a bottom-up approach to explore how variations in protein aggregates size, composition, post-translational modifications and point mutations profoundly influence their biological functions. Applying this method to Alzheimers and Parkinsons associated proteins, we uncover the mechanism of novel disease-relevant pathways and demonstrate how subtle alterations in composition and morphology can shift the balance between healthy and pathological states. Our findings establish a broadly applicable framework for investigating protein dysfunctions in various proteinopathies.

biochemistry↗

bioRxiv2023

Cooperativity and induced oligomerisation control the interaction of SARS- CoV-2 with its cellular receptor and patient-derived antibodies

Viral entry is mediated by oligomeric proteins on the virus and cell surfaces. The association is therefore open to multivalent interactions between these proteins, yet such recognition is typically rationalised as affinity between monomeric equivalents. As a result, assessment of the thermodynamic mechanisms that control viral entry has been limited. Here, we use mass photometry to overcome the analytical challenges consequent to multivalency. Examining the interaction between the spike protein of SARS-CoV-2 and the ACE2 receptor, we find that ACE2 induces oligomerisation of spike in a variant-dependent fashion. We also demonstrate that patient-derived antibodies use induced-oligomerisation as a primary inhibition mechanism or to enhance the effects of receptor-site blocking. Our results reveal that naive affinity measurements are poor predictors of potency, and introduce a novel antibody-based inhibition mechanism for oligomeric targets. One-Sentence SummaryMultivalent interactions between viral proteins, cell-surface receptors, and anti-viral antibodies regulate infection and inhibition.

biophysics↗

bioRxiv2020

Mass Photometry of Membrane Proteins

Integral membrane proteins (IMPs) are biologically highly significant but challenging to study because they require maintaining a cellular lipid-like environment. Here, we explore the application of mass photometry (MP) to IMPs and membrane mimetic systems at the single particle level. We apply MP to amphipathic vehicles, such as detergents and amphipols, as well as to lipid and native nanodiscs, characterising the particle size, sample purity and heterogeneity. Using methods established for cryogenic electron microscopy, we eliminate detergent background, enabling high-resolution studies of membrane protein structure and interactions. We find evidence that, when extracted from native membranes using native styrene-maleic acid nanodiscs, the potassium channel KcsA is present as a dimer of tetramers - in contrast to results obtained using detergent purification. Finally, using lipid nanodiscs, we show that MP can help distinguish between functional and non-functional nanodisc assemblies, as well as determine the critical factors for lipid nanodisc formation.

biophysics↗

bioRxiv2017

Quantitative mass imaging of single molecules in solution

The cellular processes underpinning life are orchestrated by proteins and their interactions. Structural and dynamic heterogeneity, despite being key to protein and drug function, continues to pose a fundamental challenge to existing analytical and structural methodologies used to study these associations. Here, we use interferometric scattering microscopy to mass-image single biomolecules in solution with <2% mass error, up to 19-kDa resolution and 1-kDa precision. Thereby, we resolve oligomeric distributions at high dynamic range, detect small-molecule binding, and mass-image biomolecules composed not only of amino acids, but also heterogeneous species, such as lipo- and glycoproteins. These capabilities enable us to characterize the molecular mechanisms of processes as diverse as oligomeric selfassembly, glycoprotein cross-linking, amyloidogenic protein aggregation, and actin polymerization. Interferometric scattering mass spectrometry (iSCAMS) provides spatially resolved access to the dynamics of biomolecular interactions ranging from those involving small molecules to mesoscopic assemblies, one molecule at a time.

biophysics↗