Inhibition of MAPK Hog1 Results in Increased Hsp104 Aggregate Formation Probably through Elevated Arsenite Influx into the Cells, an Approach with Numerous Potential Applications

Abstract

Arsenic is a highly toxic and carcinogenic metalloid widely dispersed in the environment, contaminating water and soil and accumulating in crops. Paradoxically, arsenic is also part of modern therapy and employed in treating numerous ailments and diseases. Hence, inventing strategies to tune cellular arsenic uptake based on purpose is striking. Here, we describe an approach in which the arsenite uptake can be increased using a MAPK inhibitor. Employing microfluidic flow chambers in combination with optical tweezers and fluorescent microscopy, we elevated the influx of arsenite into the yeast Saccharomyces cerevisiae cells following short-term treatment with a Hog1 kinase inhibitor. The increase in arsenite uptake was followed on arsenite triggered redistribution of a reporter protein, Hsp104-GFP, which was imaged over time. The effect was even more pronounced when the yeast mother and daughter cells were analyzed disjointedly, an opportunity provided owing to single-cell analysis. Our data firstly provide a strategy to increase arsenite uptake and secondly show that arsenite triggered aggregates, previously shown to be sites of damaged proteins, are distributed asymmetrically and less accumulated in daughter cells. Inventing approaches to tune arsenite uptake has a great value for its use in environmental as well as medical applications.

Studying Glycolytic Oscillations in Individual Yeast Cells by Combining Fluorescence Microscopy with Microfluidics and Optical Tweezers

“…Precise spatial and temporal control of the extracellular environment has been successfully applied to define the dynamics of yeast AMP‐activated kinase signaling under different glucose conditions and to characterize cell‐to‐cell variability by imaging of nuclear translocation of fluorescently tagged transcription repressor protein Mig1 (Almquist et al., ; Bendrioua et al., ; Welkenhuysen et al., ). This method has also been used to determine cellular arsenite uptake in yeast, as controlled by a mitogen‐activated protein kinase inhibitor (Ahmadpour et al., ). Furthermore, the technique has been used to determine the yeast adaptation response following osmotic stress by imaging of nuclear translocation of fluorescently tagged proteins Hog1 and Msn2 (Babazadeh et al., ; Babazadeh et al., ; Petelenz‐Kurdziel et al., ).…”