difference between membrane bound receptors and intracellular receptors. At least five points

These are peptide hormone receptors. Membrane-bound receptors are proteins located on the plasma membrane. They can be single polypeptide chains or have up to four subunits. Some of them have up to seven transmembrane domains . Some of the hormones that these receptors bind to are prostaglandins, ACTH, glucogon, catecholamines, parathyroid hormone and others. Many other hormones bind to receptors with less domains?

Intracellular receptors, as mentioned above, bind steroid hormones. All steroid hormones are derived from cholesterol, which is a hydrophobic molecule. Thus, steroid hormones can diffuse through the plasma membrane and interact with receptors found inside the cell. In contrast to peptide hormones, steroid hormones do not bind to membrane-bound receptors. Steroid receptors are also not membrane spanning proteins. They are either free floating in the cytoplasm, or they are in the nucleus. Most steroid receptors have specific sites which interact with DNA and affect transcription .These receptors are mostly found in multimeric complexes when they are inactive. Some of these structures include complexes with heat shock proteins. Complex formation of steroid hormones with these receptors release the heat shock protein and become activated. These active complexes enter the nucleus and interact with Hormone Response Elements (HRE) which enhances or sometimes represses transcription.
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