Biology subjects

Karedla, N.

Publications and source records attributed to Karedla, N..

3 recordsLinked to original sources

bioRxiv2023

Observation of E-cadherin Adherens Junctions Variation with Metal-induced Energy Transfer Imaging/Spectroscopy

Epithelial cadherin (E-cad) mediated cell-cell junctions play a crucial role in the establishment and maintenance of tissues and organs. In this study, we employed metal-induced energy transfer imaging and spectroscopy to investigate variations in intermembrane distance during adhesion between two model membranes adorned with E-cad. By correlating the measured intermembrane distances with the distinct E-cad junction states, as determined by their crystal structures, we probed the dynamic behavior and diversity of E-cad junctions across different binding pathways. Our observations led to the identification of a transient intermediate state referred to as the X-dimeric state and enabled a detailed analysis of its kinetics. We discovered that the formation of the X-dimer leads to significant membrane displacement, subsequently impacting the formation of other X-dimers. These direct experimental insights into the subtle dynamics of E-cad-modified membranes and the resultant changes in intermembrane distance provide novel perspectives on the assembly of E-cad junctions between cells. This knowledge en-hances our comprehension of tissue and organ development and may serve as a foundation for the development of innovative therapeutic strategies for diseases linked to cell-cell adhesion abnormalities. Significance StatementIn this study, we employed metal-induced energy transfer (MIET) imaging and spectroscopy to track variations in intermembrane distance during the adhesion of two membranes mediated by epithelial cadherin. Leveraging the high spatial resolution of MIET, we explored the dynamics of cadherins across various binding pathways. Furthermore, we successfully captured a transient intermediate state known as the X-dimer and revealed its ability to communicate with other X-dimers through membrane displacement. These discoveries offer valuable mechanistic insights into the dynamics of cadherin junctions.

biophysics↗

bioRxiv2023

Measuring sub-nanometer fluctuations at microsecond temporal resolution with metal- and graphene-induced energy transfer spectroscopy

Out-of-plane fluctuations, also known as stochastic displacements, of biological membranes play a crucial role in regulating many essential life processes within cells and organelles. Despite the availability of various methods for quantifying membrane dynamics, accurately quantifying complex membrane systems with rapid and tiny fluctuations, such as mitochondria, remains a challenge. In this work, we present a novel methodology that combines metal/graphene-induced energy transfer (MIET/GIET) with fluorescence correlation spectroscopy (FCS) to quantify out-of-plane fluctuations of membranes with simultaneous spatiotem-poral resolution of approximately one nanometer and one microsecond that is unprecedented. To validate the technique and spatiotemporal resolution, we measured bending undulations of model membranes. Furthermore, we demonstrate the versatility and applicability of MIET/GIET-FCS for studying diverse membrane systems, including the widely studied fluctuating membrane system of human red blood cells, as well as two unexplored membrane systems with tiny fluctuations, a pore-spanning membrane, and mitochondrial inner/outer membranes.

biophysics↗

bioRxiv2022

Metal-Induced Energy Transfer (MIET) for Live-Cell Imaging with Fluorescent Proteins

Metal-Induced Energy Transfer (MIET) imaging is an easy-to-implement super-resolution modality that achieves nanometer resolution along the optical axis of a microscope. Although its capability in numerous biological and biophysical studies has been demonstrated, its implementation for live-cell imaging with fluorescent proteins is still lacking. Here, we present its applicability and capabilities for live-cell imaging with fluorescent proteins in diverse cell types (adult human stem cells, human osteo-sarcoma cells, and Dictyostelium discoideum cells), and with various fluorescent proteins (GFP, mScarlet, RFP, YPet). We show that MIET imaging achieves nanometer axial mapping of living cellular and sub-cellular components across multiple timescales, from a few milliseconds to hours, with negligible phototoxic effects.

biophysics↗