A predictive nuclear translocation assay for spliced x-box-binding protein 1 identifies compounds with known organ toxicities.

Compound toxicity is still the main cause of attrition, emphasizing the need for novel predictive assays to identify toxic compounds early during drug development. Endoplasmic reticulum (ER) stress has recently been discovered as a molecular event that links cellular dysfunction to drug-induced organ toxicity in humans. Among higher organisms the inositol-requiring transmembrane kinase/endoribonuclease pathway plays a major role in mediating the ER stress response.

Agonist-independent, high constitutive activity of the human melanocortin 1 receptor.

The melanocortins (alpha-melanocyte-stimulating hormone and adrenocorticotropin) act on epidermal melanocytes to increase melanogenesis, the eumelanin/pheomelanin ratio and dendricity. These actions are mediated by the heptahelical melanocortin 1 receptor (MC1R), positively coupled to adenylyl cyclase. Gain-of-function mouse Mc1r alleles are associated with a dark, eumelanic coat.

Rate limiting factors in melanocortin 1 receptor signalling through the cAMP pathway.

The melanotropic actions of alpha-melanocyte-stimulating hormone (alpha-MSH) and other melanocortins are mediated by activation of the melanocortin 1 receptor (MC1R). This G protein-coupled receptor is positively coupled to Gs and triggers the cyclic adenosine mono-phosphate (cAMP) pathway. Mutations of the MC1R gene are associated with skin type and pigmentation phenotypes, and with increased risk of skin cancers.