Volume 12 Issue 11, November 2011

New findings challenge the idea that sirtuins promote longevity.

Describes how a minimal oscillatory cyclin–CDK module can drive the cell cycle.

PRMT5 methylates RAF proteins to decrease their stability and reduce ERK activation.

NR4A proteins regulate DNA double-strand break repair independently of transcription.

USP1 stabilizes ID proteins to inhibit differentiation in MSCs and osteosarcoma.

Midbodies promote stem cell pluripotency and cancer tumorigenicity.

Slower-cycling stem cells compensate for LGR5-expressing crypt base columnar cells.

Shows crosstalk between histone H2B ubiquitylation and Dam1 methylation at kinetochores.

The diverse components of the nucleoskeleton provide physical links, and allow communication, between the cytoskeleton and the nucleus. Together, they form dynamic networks that regulate the shape and mechanical properties of the nucleus and control nuclear function, including gene expression.

Microtubule nucleation is regulated by the γ-tubulin small complex (γTuSC) and the γ-tubulin ring complex (γTuRC). Recent structural work, including the crystallographic analysis of γ-tubulin complex protein 4 (GCP4), provides new insights into the mechanism of γTuRC-based microtubule nucleation, confirming the hypothesis that the γTuRC functions as a microtubule template.

The differentiation of adipocytes from mesenchymal stem cells, known as adipogenesis, occurs in two stages, commitment and terminal differentiation, both of which are tightly regulated by mechanical and molecular cues. A better understanding of the underlying mechanisms may identify therapeutic targets for metabolic diseases.

The N-end rule defines the protein-destabilizing activity of a given amino-terminal residue following its post-translational modification. The N-end rule pathway is emerging as a major cellular proteolytic system, and recent studies provide insights into its components, substrates and functions, as well as the structural basis of substrate recognition.

Advances in biosensor technology have made it possible to simultaneously study the activation of multiple signalling network components in the same cell. This approach has been enhanced by novel computational approaches (referred to as computational multiplexing) that can reveal relationships between network nodes imaged in separate cells.

Caspase 8 initiates apoptosis but also has non-apoptotic roles during embryonic development and for immune cell proliferation. Recent findings indicate that the non-apoptotic functions of caspase 8 are defined by the suppression of receptor-interacting protein kinase 3 (RIPK3), a kinase that triggers programmed necrosis.