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Sigma 1
The sigma-1 receptor (σ1R), one of two sigma receptor subtypes, is a Chaperone (protein), chaperone protein at the endoplasmic reticulum (ER) that modulates calcium signaling through the IP3 receptor. In humans, the σ1 receptor is encoded by the ''SIGMAR1'' gene. The σ1 receptor is a transmembrane protein expressed in many different tissue types. It is particularly concentrated in certain regions of the central nervous system. It has been implicated in several phenomena, including cardiovascular function, schizophrenia, clinical depression, the effects of cocaine abuse, and cancer. Much is known about the binding affinity of hundreds of synthetic compounds to the σ1 receptor. An endogenous ligand (biochemistry), ligand for the σ1 receptor has yet to be conclusively identified, but tryptaminergic trace amines and neuroactive steroids have been found to activate the receptor. Especially progesterone, but also testosterone, pregnenolone sulfate, and dehydroepiandrosterone sul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigma Receptor
Sigma receptors (σ-receptors) are protein cell surface receptors that bind ligands such as 4-PPBP (4-phenyl-1-(4-phenylbutyl) piperidine), SA 4503 (cutamesine), ditolylguanidine, dimethyltryptamine, and siramesine. There are two subtypes, sigma-1 receptors (σ1) and sigma-2 receptors (σ2), which are classified as sigma receptors for their pharmacological similarities, even though they are evolutionarily unrelated. The fungal protein ERG2, a C-8 sterol isomerase, falls into the same protein family as sigma-1. Both localize to the ER membrane, although sigma-1 is also reported to be a cell surface receptor. Sigma-2 is an EXPREA domain protein (citation needed) with a mostly intracellular (ER membrane) localization. Classification Because the σ-receptor was originally discovered to be agonized by benzomorphan opioids and antagonized by naltrexone, σ-receptors were originally believed to be a type of opioid receptor. When the σ1 receptor was isolated and cloned, it was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |