Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
It was widely accepted that cytoplasmic actin operates as filaments and nuclear actin is mainly monomeric. Recent progress in the field, including the association of actin filament assembly proteins with nuclear functions and the first direct visualizations of polymerized nuclear actin, forces us to rethink this issue.
The extracellular matrix (ECM) is a key component of the stem cell niche and is now emerging as more than just an inert scaffold. Indeed, new technologies have provided mechanistic insights into the effects of the ECM on stem cell fate choice.
Amino acids are one of the key environmental stimuli signalling to mTOR. Although exactly how they are sensed and how they activate mTOR has remained elusive, a model has emerged that implicates signalling by RAG GTPases, Ragulator and v-ATPase at the lysosome and leucyl t-RNA synthetase in the cytoplasm.
