A procedure to deposit fiducial markers on vitreous cryo-sections for cellular tomography.

We describe a novel approach for the accurate alignment of images in electron tomography of vitreous cryo-sections. Quantum dots, suspended in organic solvents at cryo-temperatures, are applied directly onto the sections and are subsequently used as fiducial markers to align the tilt series. Data collection can be performed from different regions of the vitreous sections, even when the sections touch the grid only at a few places.

A new class of peroxisome proliferator-activated receptor agonists with a novel binding epitope shows antidiabetic effects.

The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the NR1 subfamily of nuclear receptors. The PPARs play key roles in the control of glucose and lipid homeostasis, and the synthetic isoform-specific PPAR agonists are used clinically to improve insulin sensitivity and to lower serum triglyceride levels. All of the previously reported PPAR agonists form the same characteristic interactions with the receptor, which have been postulated to be important for the induction of agonistic activity.

Crystal structure of the heterodimeric complex of LXRalpha and RXRbeta ligand-binding domains in a fully agonistic conformation.

The nuclear receptor heterodimers of liver X receptor (LXR) and retinoid X receptor (RXR) are key transcriptional regulators of genes involved in lipid homeostasis and inflammation. We report the crystal structure of the ligand-binding domains (LBDs) of LXRalpha and RXRbeta complexed to the synthetic LXR agonist T-0901317 and the RXR agonist methoprene acid (Protein Data Base entry 1UHL). Both LBDs are in agonist conformation with GRIP-1 peptides bound at the coactivator binding sites.

A triple mutant of the Drosophila ERR confers ligand-induced suppression of activity.

The steroid hormone (NR3) subfamily of nuclear receptors was until recently believed to be restricted to deuterostomes. However, a novel nuclear receptor belonging to the NR3 subfamily was recently identified in the Drosophila melanogaster genome, indicating the existence of an ancestor before the evolutionary split of deuterostomes and protostomes. This receptor, termed the Drosophila estrogen-related receptor (dERR), most closely resembles the human and mouse estrogen-related receptors (ERRs) in both the DNA binding domain (DBD) (approximately 85% identical) and the ligand binding domain (LBD) (approximately 35% identical).

Identification of residues in the PXR ligand binding domain critical for species specific and constitutive activation.

The cytochrome P450 family of enzymes has long been known to metabolize a wide range of compounds, including many of today's most common drugs. A novel nuclear receptor called PXR has been established as an activator of several of the cytochrome P450 genes, including CYP3A4. This enzyme is believed to account for the metabolism of more than 50% of all prescription drugs.