BISC401 Midterm: Exam 3
5 Dec 2016
School
Department
Course
Professor
Document Summary
Lipid-soluble hormones are extracellular signals that regulate the activities of transcription factors: they can diffuse through the plasma and nuclear membranes and interact directly with the transcription factors they control, this is due to their hydrophobicity. Example of hormones that bind to nuclear receptors in the cytosol or nuclear: cortisol, retinoic acid, thyroxine. Each nuclear receptor has three functional region: 1. May contain one or more activation domain: 2. Contains a repeat of the c4 zinc finger motif: 3. Hormones binding to a nuclear receptor regulates its activity as a transcription factor. Fusion proteins demonstrate hormone-binding domain of gr (glucocorticoid receptor) proteins mediates translocation to the nucleus in the presence of hormone. Without hormone, gr cannot be transported into the nucleus. In cells that expressed -galactosidase alone: the enzyme was localized to the cytoplasm in the presence and absence of the glucocorticoid hormone.
