Direct observation of motor protein stepping in living cells using MINFLUX.

Dynamic measurements of molecular machines can provide invaluable insights into their mechanism, but these measurements have been challenging in living cells. Here, we developed live-cell tracking of single fluorophores with nanometer spatial and millisecond temporal resolution in two and three dimensions using the recently introduced super-resolution technique MINFLUX. Using this approach, we resolved the precise stepping motion of the motor protein kinesin-1 as it walked on microtubules in living cells.

Adsorption of galloyl catechin aggregates significantly modulates membrane mechanics in the absence of biochemical cues.

Physical interactions of four major green tea catechin derivatives with cell membrane models were systemically investigated. Catechins with the galloyl moiety caused the aggregation of small unilamellar vesicles and an increase in the surface pressure of lipid monolayers, while those without did not. Differential scanning calorimetry revealed that, in a low concentration regime (≤10 μM), catechin molecules are not significantly incorporated into the hydrophobic core of lipid membranes as substitutional impurities.

The regulatable MAL32 promoter in Saccharomyces cerevisiae: characteristics and tools to facilitate its use.

Here we describe a set of tools to facilitate the use of maltose and the MAL32 promoter for regulated gene expression in yeast, alone or in combination with the GAL1 promoter. Using fluorescent protein reporters we find that under non-inducing conditions the MAL32 promoter exhibits a low basal level of expression, similar to the GAL1 promoter, and that both promoters can be induced independently of each other using the respective sugars, maltose and galactose. While their repression upon glucose addition is immediate and complete, we found that the MAL32 and GAL1 promoters each exhibit distinct induction kinetics.