Although the prion protein (PrP) is best known as a glycosylphosphatidylinositol-anchored cell surface glycoprotein lacking canonical nucleic acid-binding domains, accumulating evidence indicates that it can be localized in the cytosol and nucleus and exhibits a remarkable ability to interact with both RNA and DNA molecules. A wide range of nucleic acids have been identified as PrP interactors, including cellular and viral RNAs, genomic and mitochondrial DNA, as well as highly structured nucleic acid motifs. For instance, G-quadruplexes and DNA hairpin aptamers, often display particularly high affinity for PrP. These observations suggest that PrP’s nucleic acid binding property is a potentially overlooked part of PrP biology, with possible implications for its physiological functions and pathological roles, including the formation of biomolecular condensates. While such condensates might participate in the spatiotemporal organization of PrP biological activities, their aging into less dynamic, gel- or solid-like assemblies could also contribute to pathological protein aggregation linked to prion disease pathogenesis. Herein, we review the literature about nuclear-associated PrP and discuss its molecular features relevant to nucleic-acid binding. Furthermore, we argue that PrP might harbor previously underappreciated nuclear functions as supported by microscopy and biochemical evidence reporting intranuclear and perinuclear PrP. We propose that this understudied nuclear localization of PrP might stem from the historical focus on membrane-associated PrP, and we call for renewed attention to its potential nuclear activities.
Blood microrheology and microcirculation is a vast field of research focusing on the properties of blood passing through lesser vessels and capillaries. In this part of the circulatory system, red blood cells (RBCs) determine the parameters of the flow, which impact the efficiency of oxygen transport and tissue supply. Various pathologies, such as cardiovascular diseases, diabetes mellitus, malaria and sickle cell disease alter parameters of RBCs severely impairing microcirculation. RBC abilities of reversible aggregation and deformation are among the main cellular properties ruling the hemorheology and microcirculation. In this review, we discuss five methods for blood microrheology and microcirculation in vitro studies: optical tweezers, flow chamber-coupled microscopy, laser aggregometry, laser diffractometry (ektacytometry) and flow cytometry. These techniques allow for assessing valuable cellular properties without significant damage to the cells during measurements. Some of the methods are used for studies on the scale of single cells, while others provide summarized parameters of thousands of cells. The possibilities of these techniques to study RBC aggregation and deformability are considered along with recent advances and current limitations.
Plant growth is a mechanical process in which turgor-generated tension stretches the cell wall, while irreversible expansion depends on wall relaxation, creep, and yielding. Plant biomechanics can be investigated using a wide range of techniques, often integrated with computational modeling. Yet these methods differ in the scale, direction, and loading mode they probe. This review highlights the distinctive role of extensometry in measuring living tissue responses to controlled in-plane tension, a loading mode closely related to the tensile state generated during turgor-driven expansion. Apparent tensile modulus and rupture characterize resistance and failure, whereas creep and stress relaxation probe time-dependent behavior more closely related to irreversible wall expansion. Tensile experiments can also quantify recovery, residual strain, anisotropy, and work to failure. Optical tracking, confocal imaging, and finite element modeling help connect these sample-scale responses to local deformation and tissue structure. At the same time, tensile data require careful interpretation because apparent tissue stiffness integrates wall material behavior with turgor, cell geometry and patterning, wall thickness, hydration, and boundary conditions. Here, we discuss applications in different plant organs and cell wall mutants and highlight open hardware, automated imaging, and multiscale modeling as routes toward a more quantitative plant mechanobiology. We outline how paired loading and recovery protocols, constitutive models, and independent measurements can constrain reversible deformation, persistent strain, and growth-relevant parameters.
Liquid–liquid phase separation (LLPS) underlies the formation of biomolecular condensates that spatially and temporally organize cellular biochemistry in the absence of membrane boundaries. These assemblies are intrinsically dynamic, arising from weak and multivalent interactions, and span a continuum of material states rather than discrete phases. Consequently, defining condensate state requires more than morphological inspection or single-parameter measurements. Fluorescence-based quantitative microscopy provides critical access to the physical properties of phase-separated systems. Fluorescence correlation spectroscopy (FCS)-based approaches analyze fluorescence fluctuations and correlation functions to estimate molecular concentration, apparent diffusion, residence time, exchange, binding-related kinetics, and dynamic heterogeneity under defined optical and analytical assumptions, whereas fluorescence lifetime imaging microscopy (FLIM) measures fluorophore excited-state decay and provides probe-dependent lifetime or phasor readouts that are sensitive to local physicochemical environments. When implemented on a confocal platform, FLIM and FCS yield orthogonal, spatially resolved observables that jointly constrain interpretations of condensate dynamics and material properties. This Review discusses how multidimensional FLIM–FCS approaches reveal subtle or partially decoupled changes in molecular dynamics and microenvironment that may escape conventional imaging, thereby enabling a more rigorous distinction between reversible physiological condensates and pathological assemblies.
What happens when you poke a living cell, applying a localized external force to its surface? The answer depends, in part, on how long you keep poking. The plasma membrane and the actomyosin cortex beneath it form a mechanically active interface that changes in disease and can itself be reshaped by force. This review explores how the cell surface responds to such force in two overlapping experimental regimes. Poke briefly, over seconds, and force becomes a readout, revealing biophysical parameters that report on cell state and serve as candidate single-cell markers of disease. Keep poking, over minutes, and force can remodel the surface, suggesting that it may act not only as a perturbation but also as an instructive signal. What emerges is a mechanical fingerprint whose potential for diagnosis, disease monitoring, and, eventually, controlled manipulation of cell surfaces is only beginning to be understood.
