What is the Origin of Nuclear Receptor Signaling?

The term describes the location and function of this key receptor family, combining 'Nuclear Receptor' (a protein found within or translocating to the cell nucleus) with 'Signaling' (the process of transmitting a biological message). The understanding of these receptors was crucial in distinguishing the mechanisms of action for lipid-soluble hormones from those of water-soluble peptide hormones.

What is the Mechanism of Nuclear Receptor Signaling?

The mechanism involves the lipophilic hormone diffusing across the cell membrane and binding to the inactive nuclear receptor. This binding event causes a critical conformational change in the receptor, leading to its dimerization and translocation to the nucleus. Once activated, the receptor complex binds to specific DNA sequences, known as hormone response elements, recruiting co-activator or co-repressor proteins to either increase or decrease the transcription rate of target genes, resulting in the production of new proteins that alter cellular function.

Nuclear Receptor Signaling

Meaning

Nuclear Receptor Signaling is a primary mechanism of gene regulation mediated by a family of intracellular proteins that act as ligand-activated transcription factors, residing either in the cytoplasm or the nucleus. These receptors, which include those for steroid hormones, thyroid hormones, and vitamin D, bind to their respective lipophilic hormones and then directly modulate the transcription of target genes. This pathway is the fundamental means by which lipid-soluble hormones exert their long-term, systemic effects on development, metabolism, and reproductive function.