Commentary: Important lessons from the unfolding health crisis in Venezuela

The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...

Source: Schlimpert, S., et al. Fluorescence Time-lapse Imaging of the Complete S. venezuelae Life Cycle Using a Microfluidic Device. J. Vis. Exp. (2016)This video demonstrates the cultivation and isolation of spores from Streptomyces venezuelae. Spores, dormant cells that help bacteria survive stress, are produced during nutrient limitation and collected through centrifugation. The method ensures a pure, cold-stored spore suspension for downstream...

Streptomyces are characterized by a complex life cycle that has been experimentally challenging to study by cell biological means. Here we present a protocol to perform fluorescence time-lapse microscopy of the complete life cycle by growing Streptomyces venezuelae in a microfluidic...

Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...

Source: Schlimpert, S. et al. Fluorescence Time-lapse Imaging of the Complete S. venezuelae Life Cycle Using a Microfluidic Device. J. Vis. Exp. (2016)This video demonstrates fluorescence time-lapse imaging of the complete life cycle of the bacteria Streptomyces venezuelae using a microfluidic device to visualize germination, hyphal growth, and sporulation in real...

Source: Dahl, J. et al. Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo. J. Vis. Exp. (2016)This video demonstrates a fluorescence spectrophotometer-based assay to evaluate chaperone activity on a substrate protein under acid and heat stress. It outlines the steps for monitoring substrate unfolding and aggregation through light scattering, comparing conditions with and without the...