Developmental Biology: Holding Pattern for Histones

Trip13 Depletion in Liver Cancer Induces a Lipogenic Response Contributing to Plin2-Dependent Mitotic Cell Death

Aberrant energy metabolism and cell cycle regulation both critically contribute to malignant cell growth and both processes represent targets for anticancer therapy. It is shown here that depletion of the AAA+-ATPase thyroid hormone receptor interacting protein 13 (Trip13) results in mitotic cell death through a combined mechanism linking lipid metabolism to aberrant mitosis. Diminished Trip13 levels in hepatocellular carcinoma cells result in insulin-receptor-/Akt-pathway-dependent accumulation of lipid droplets, which act as functional acentriolar microtubule organizing centers disturbing mitotic spindle polarity. Specifically, the lipid-droplet-coating protein perilipin 2 (Plin2) is required for multipolar spindle formation, induction of DNA damage, and mitotic cell death. Plin2 expression in different tumor cells confers susceptibility to cell death induced by Trip13 depletion as well as treatment with paclitaxel, a spindle-interfering drug commonly used against different cancers. Thus, assessment of Plin2 levels enables the stratification of tumor responsiveness to mitosis-targeting drugs, including clinically approved paclitaxel and Trip13 inhibitors currently under development.

Modulation of the organelle specificity in Re(i) tetrazolato complexes leads to labeling of lipid droplets

Neutral Re(i) tetrazolato complexes exhibit labeling of lipid droplets with high specificity.

Proteins under new management: lipid droplets deliver

Lipid droplets are ubiquitous organelles that store neutral lipids and have crucial roles in lipid metabolism. Recent studies have uncovered many examples of lipid droplets recruiting proteins from other cellular compartments, in a cell type-specific and regulated manner. Some droplet-recruited proteins are destined for destruction, whereas others are released and reused when conditions change. Droplets might therefore have a general role in managing the availability of proteins, and they have been proposed to serve as generic sites of protein sequestration. The implications of this emerging role of lipid droplets include regulated inactivation of proteins, prevention of toxic protein aggregates and localized delivery of signaling molecules.