| ryanodine receptor calcium release channel | Protein complexes that mediate the release of calcium from the sarcoplasmic reticulum in both skeletal and cardiac muscle cells by forming tetrametric complexes. These complexes each then act as a calcium channel. There are three isoforms of the ryr: ryr1, ryr2, and ryr3. Ryr1 is specifically expressed in skeletal muscles and ryr2 in cardiac muscles. Ryr3 is yet another isoform found in non-muscle cells such as neuronal cells. (12 Dec 1998) |
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| PL7a receptor-tyrosine kinase | <enzyme> A member of the eph receptor tyrosine kinase subfamily; shows 80% identity with myk-1; genbank l43622 Registry number: EC 2.7.1.- Synonym: pl7a protein (26 Jun 1999) |
| Con A receptor | <biochemistry> A common misuse of the term receptor. Con A binds to the mannose residues of many different glycoproteins and glycolipids and the binding is therefore not to a specific site. It could be argued that the receptor is the Con A and cells have Con A ligands on their surfaces: certainly this would be less confusing. (05 Jan 1998) |
| muscarinic acetylcholine receptor | Distinct from the nicotinic ACh receptor in having no intrinsic ion channel, the receptor is formed from one protein chain with 7 transmembrane regions. The receptors produce their effect via activation of GTP-binding proteins. (18 Nov 1997) |
| muscarinic receptor kinase | <enzyme> Phosphorylates muscarinic acetylcholine receptors and beta-adrenergic receptors Registry number: EC 2.7.- Synonym: muscarinic acetylcholine receptor kinase, machr kinase (26 Jun 1999) |
| 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) |
| 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) |