SUMMARY
Glycogen synthase kinase 3 (GSK3) plays a central role in diverse
cellular processes. GSK3 has two mammalian isozymes, GSK3α and
GSK3β, whose functions remain ill-defined because of a lack of
inhibitors that can distinguish between the two highly homologous isozymes.
Here, we show that GSK3α and GSK3β can be selectively inhibited
in mouse embryonic stem cells (ESCs) using a chemical-genetic approach.
Selective inhibition of GSK3β is sufficient to maintain mouse ESC
self-renewal, whereas GSK3α inhibition promotes mouse ESC
differentiation toward neural lineages. Genome-wide transcriptional analysis
reveals that GSK3α and GSK3β have distinct sets of downstream
targets. Furthermore, selective inhibition of individual GSK3 isozymes yields
distinct phenotypes from gene deletion, highlighting the power of the
chemical-genetic approach in dissecting kinase catalytic functions from the
protein’s scaffolding functions. Our study opens new avenues for
defining GSK3 isozyme-specific functions in various cellular processes.
Acid–base extraction is an
important concept in organic
chemistry that beginning students often find challenging to comprehend.
Herein, we describe the use of a simple demonstration suitable for
lecture that allows students to visually track the chemical events
that take place in a separatory funnel. The demonstration involves
the use of two safe and available dyes with different acid–base
properties, phenolphthalein and neutral red. The dyes present distinct
colors in their ionic and nonionic forms. With a change in the pH
of the media in the separatory funnel, the colors of the solutions
change according to the compounds’ ionic states and their solubilities
in either the aqueous or the organic layers. This provides a visual
record of chemical concepts, which helps students to better understand
the partition of different molecules between the organic and aqueous
layers in an extraction process. In addition, we provide resources
describing how to use this demonstration in class aiming to enhance
students’ engagement and comprehension of the topic.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.