Biology subjects

Drubin, D.

Publications and source records attributed to Drubin, D..

3 recordsLinked to original sources

bioRxiv2025

A Multimodal Adaptive Optical Microscope For In Vivo Imaging from Molecules to Organisms

Understanding biological systems requires observing features and processes across vast spatial and temporal scales, spanning nanometers to centimeters and milliseconds to days, often using multiple imaging modalities within complex native microenvironments. Yet, achieving this comprehensive view is challenging because microscopes optimized for specific tasks typically lack versatility due to inherent optical and sample handling trade-offs, and frequently suffer performance degradation from sample-induced optical aberrations in multicellular contexts. Here, we present MOSAIC, a reconfigurable microscope that integrates multiple advanced imaging techniques including light-sheet, label-free, super-resolution, and multi-photon, all equipped with adaptive optics. MOSAIC enables non-invasive imaging of subcellular dynamics in both cultured cells and live multicellular organisms, nanoscale mapping of molecular architectures across millimeter-scale expanded tissues, and structural/functional neural imaging within live mice. MOSAIC facilitates correlative studies across biological scales within the same specimen, providing an integrated platform for broad biological investigation.

cell biology↗

bioRxiv2022

Cik1 and Vik1 Accessory Proteins Confer Distinct Functions to the Kinesin-14, Kar3

The budding yeast Saccharomyces cerevisiae has a closed mitosis in which the mitotic spindle and cytoplasmic microtubules (MTs) used to segregate chromosomes remain separated by the nuclear envelope throughout the cell cycle. Kar3, the yeast kinesin-14, has unique roles in both compartments and has been implicated in capturing unattached kinetochores, stabilizing crosslinked interpolar microtubules (MT), and creating intranuclear and cytoplasmic MT arrays at the spindle pole body for kinetochore capture and karyogamy, respectively. Here, we show that two proteins, Cik1 and Vik1, that form heterodimers with Kar3, regulate its localization and function within the cell and along MTs in a cell cycle-dependent manner. Using a cell cycle synchronized, yeast MT dynamics reconstitution assay in cell lysate, we found that Kar3Vik1 induces MT catastrophes in S phase and metaphase and limits MT polymerization in G1 and anaphase. In contrast, Kar3Cik1 is a catastrophe and pause promoter in G1, while increasing catastrophes in metaphase and anaphase. Adapting this assay to track single-molecules, we saw that Kar3Cik1 is necessary for tracking MT plus-ends in S phase and metaphase, but, surprisingly, not during anaphase. These experiments demonstrate how the binding partners of Kar3 modulate its diverse functions both spatially and temporally. SUMMARY STATEMENTWe show through biochemical reconstitution experiments and live-cell imaging that the functions and localization of the budding yeast kinesin-14, Kar3, are dictated by which of its two accessory protein binding partners, Cik1 or Vik1, it binds to and by the cell cycle stage.

cell biology↗

bioRxiv2017

Nanoscale Manipulation Of Membrane Curvature For Probing Endocytosis In Live Cells

Clathrin-mediated endocytosis (CME) involves nanoscale bending and inward budding of the plasma membrane, by which cells regulate both the distribution of membrane proteins and the entry of extracellular species1,2. Extensive studies have shown that CME proteins actively modulate the plasma membrane curvature1,3,4. However, the reciprocal regulation of how plasma membrane curvature affects the activities of endocytic proteins is much less explored, despite studies suggesting that membrane curvature itself can trigger biochemical reactions5-8. This gap in our understanding is largely due to technical challenges in precisely controlling the membrane curvature in live cells. In this work, we use patterned nanostructures to generate well-defined membrane curvatures ranging from +50 nm to -500 nm radius of curvature. We find that the positively curved membranes are CME hotspots, and that key CME proteins, clathrin and dynamin, show a strong preference toward positive membrane curvatures with a radius < 200 nm. Of ten CME related proteins we examined, all show preferences to positively curved membrane. By contrast, other membrane-associated proteins and non-CME endocytic protein, caveolin1, show no such curvature preference. Therefore, nanostructured substrates constitute a novel tool for investigating curvature-dependent processes in live cells.

cell biology↗