Nuclear receptors for steroid

Nuclear receptors for steroid - Nuclear receptors are...

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Nuclear receptors are ligand-modulated gene regulatory proteins -various small hydrophobic signal molecules diffuse directly across the plasma membrane of target cells and bind to intracellular receptors that are gene regulatory proteins. These signal molecules include steroid hormones, thyroid hormones, retinoids, and vitamin D. Although they differ greatly from another in both chemical structure and function, they all act by similar mechanism. They bind to their respective intracellular receptor proteins and alter the ability of these proteins to control the transcription of specific genes. Thus, these proteins serve both as intracellular receptors and as intracellular effectors for the signal. The receptors are all structurally related, being part of the very large nuclear receptor superfamily. Many family members have been identified by DNA sequencing only, and their ligand is not yet known; these proteins are therefore referred to as orphan nuclear receptors. Currently, more than half of the 48 nuclear receptors encoded in the human genome are orphans. Some mammalian nuclear receptors are regulated by intracellular metabolites rather than by secreted signal molecules; the PPAR(peroxisome proliferation activated receptors) for example, bind intracellular lipid metabolites and regulate the transcription of genes involved in lipid metabolism and fat cell differentiation. It seems likely that the nuclear receptors for
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This note was uploaded on 10/13/2011 for the course NS 3200 at Cornell University (Engineering School).

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Nuclear receptors for steroid - Nuclear receptors are...

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