Where are intracellular receptors located?

Intracellular receptors are specialized proteins located inside the cell, specifically in the cytoplasm or the nucleus. These receptors play a critical role in cellular signaling by binding to specific ligands, such as hormones or other signaling molecules that can pass through the cell membrane due to their hydrophobic nature. Once the ligand binds to the receptor, it can lead to changes in gene expression, thus influencing various cellular processes.

Understanding the location of these receptors is crucial because it distinguishes them from membrane-bound receptors, which are found on the cell surface and interact with external signaling molecules. Intracellular receptors allow for a direct response to signals that can diffuse across the lipid bilayer of the membrane. This mechanism is fundamental in many hormonal signaling pathways, such as the actions of steroid hormones and thyroid hormones, which require access to the cell's interior to elicit their functions.