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.
How the building blocks of life came together to form the first membranes and cells is perhaps the biggest unresolved question in biology. A major difference in several proposed models is whether the cytoplasm evolved inside or outside of a liposomal vesicle.
According to the free-radical theory, oxidizing species — including hydrogen peroxide (H2O2) — are generated during aerobic respiration and cause molecular damage and ageing. However, recent evidence suggests that H2O2that is produced as a signalling molecule by a selected genetic programme regulates ageing.
Convergent mechanisms limit the amount of cellular damage and thereby protect against both cancer and ageing, whereas divergent mechanisms prevent excessive proliferation and, therefore, prevent cancer but promote ageing. The net balance between these mechanisms ensures a healthy, cancer-free lifespan until late adulthood in most individuals.
When quiescent cells re-enter the cell cycle, why do they require several extra hours in the G1 phase before they replicate their DNA? One hypothesis is that the proteins that are required for the formation of pre-replicative complexes are removed from chromatin.
In vitroembryonic stem (ES)-cell studies present a unique set of tools to understand embryonic development; however, these studies face many challenges. What are the current and future strategies for the exploitation of ES cells in developmental cell biology?
Transport of soluble proteins into the nucleus depends either on binding a protein-transport complex or on being small enough to diffuse in. Recent studies indicate that the delivery of integral membrane proteins into the inner nuclear membrane is governed by the same rules.
Recent studies have identified some of the factors that are involved in WNT secretion and have brought the focus of WNT research to the issue of how WNT proteins are secreted. What are the possible mechanisms that underlie this process?
Organelles adopt many complex and dynamic shapes that are often conserved throughout evolution. We are only beginning to understand the mechanisms by which organelle shape is generated and maintained and how, even in the same organelle, different morphologies are created.
Recent findings challenge the view that γ-tubulin-dependent formation of new microtubules is restricted to conventional microtubule-organizing centres and indicate that the spatio-temporal control of microtubule nucleation is more complex than was previously thought. So, how, where and when are microtubules made?
The chromatoid body, a unique cloud-like structure of male germ cells, has puzzled scientists for years. Recent findings indicate that microRNA and RNA-decay pathways converge at the chromatoid body, which might function as a germ-cell-specific RNA-processing centre.
