| cyclic AMP receptor protein | A transcriptional regulator in prokaryotes which, when activated by binding cyclic AMP, acts at several promoters. Cyclic AMP receptor protein was originally identified as a catabolite gene activator protein. It was subsequently shown to regulate several functions unrelated to catabolism, and to be both a negative and a positive regulator of transcription. Cell surface cyclic AMP receptors are not included (cyclic AMP receptors), nor are the eukaryotic cytoplasmic cyclic AMP receptor proteins, which are the regulatory subunits of cyclic AMP-dependent protein kinases. (12 Dec 1998) |
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| presynaptic receptor | <physiology> Receptors located on presynaptic terminals at synapses. (05 Mar 1998) |
| progesterone receptor assay | The progesterone receptor test (PgR assay) checks the tumour for its hormone status. (16 Dec 1997) |
| Xiphophorus melanoma receptor kinase | <enzyme> Growth factor receptor protein with an extracellular ligand binding domain and an intracellular catalytic domain Registry number: EC 2.7.1.- Synonym: xmrk protein (26 Jun 1999) |
| selective oestrogen-receptor modulator | <pharmacology> An antioestrogen which possesses some, but not all, of the actions of oestrogen. For example, raloxifene (evista) is classified as a SERM because it prevents bone loss (like oestrogen) and lowers serum cholesterol (like oestrogen) but (unlike oestrogen) does not stimulate the endometrial lining of the uterus. Acronym: SERM (17 Jul 2002) |
| hormone receptor assay | A diagnostic test to determine whether a breast cancer's growth is influenced by hormones or if it can be treated with hormones. (09 Oct 1997) |
| purinergic receptor | <biochemistry> Receptors that use purine nucleotides (e.g. ATP) as ligands. (18 Nov 1997) |
| signal recognition particle receptor | Receptor for the signal recognition particle (SRP) found in the membrane of the endoplasmic reticulum. Also called docking protein. Heterodimeric, both protomers having GTP binding capacity, though dissimilar binding sites. Not until the complex of SRP, ribosome, message and nascent polypeptide chain binds to the SRP receptor is the block to further chain elongation released and concurrently the SRP is released, leaving the ribosome attached to the endoplasmic reticulum membrane. Cotranslational transport of the polypeptide delivers it into the lumen of the ER. (18 Nov 1997) |
| S-receptor kinase | <enzyme> Srk - s-receptor kinase; from brassica oleracea; amino acid sequence has been determined Registry number: EC 2.7.1.- Synonym: srk gene product (26 Jun 1999) |
| steroid receptor | Family of nuclear transcription factors, most of which are receptors for hormones of the steroid family, for example androgen, oestrogen, glucocorticoid, mineralocorticoid, progesterone, retinoic acid, ecdysone, thyroid hormone and the Drosophila transcription factors knirps, ultraspiracle and seven up. This family contains a conserved domain (the steroid finger motif) containing two C4 type zinc fingers. (18 Nov 1997) |
| nicotinic acetylcholine receptor | Integral membrane protein of the postsynaptic membrane to which acetylcholine binds. The receptor contains an integral ion channel, as a result of binding of acetylcholine, ion channels in the subsynaptic membrane are opened. at the neuromuscular junction, the nicotinic acetylcholine receptor initiates muscle contraction. Currently the best characterised ion channel protein: made of a hetero pentamer of related subunits, although a homo pentamer is functional in insects. Structural studies show that the acetylcholine binding site and the ionic channel are part of the same macromolecular unit. The nAChR mediates rapid transduction events (1ms) whereas receptors activating G-protein coupled channels operate on slower time scales (millisecond to second range). (18 Nov 1997) |
| nicotinic cholinergic receptor | A class of receptors responsive to acetylcholine that also are activated by nicotine; ganglionic (including the adrenal medulla) and neuromuscular receptors. Two classes exist: nicotinic-neuronal and nicotinic-muscular. (05 Mar 2000) |
| NMDA receptor | A type of glutamate receptor that participates in excitatory neurotransmission and also binds N-methyl-d-aspartate; may be particularly involved in the cell damage observed in individuals with Huntington's disease. (05 Mar 2000) |
| N methyl D aspartate receptor | <physiology> Glutamate receptor sub type (see excitatory amino acids). N methyl D aspartate receptor channels seem to be potentiated by intracellular arachidonic acid. Acronym: NMDA (26 Mar 1998) |
| quisqualate receptor | <cell biology> Glutamate operated ion channel. See: excitatory amino acid receptor channels. (05 Feb 1998) |