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  • cholesterol
  • STARD5 binds both cholesterol and 25-hydroxycholesterol and appears to function to redistribute cholesterol to the endoplasmic reticulum with which the protein associates and/or the plasma membrane. (wikipedia.org)
  • Cholesterol homeostasis is regulated, at least in part, by sterol regulatory element (SRE)-binding proteins (e.g. (wikipedia.org)
  • The steroidogenic acute regulatory protein, commonly referred to as StAR (STARD1), is a transport protein that regulates cholesterol transfer within the mitochondria, which is the rate-limiting step in the production of steroid hormones. (wikipedia.org)
  • While StAR may bind cholesterol itself, the exorbitant number of cholesterol molecules that the protein transfers would indicate that it would have to act as a cholesterol channel instead of a shuttle. (wikipedia.org)
  • Most importantly, the interior of the protein encompasses a 26 × 12 × 11-Angstrom hydrophobic tunnel that is apparently large enough to bind a single cholesterol molecule. (wikipedia.org)
  • In humans, cholesterol synthesis begins with the mevalonate pathway (see diagram), leading to the synthesis of farnesyl pyrophosphate (FPP). (wikipedia.org)
  • In humans, the main pathway leading to cholesterol is known as the Kandutsch-Russell pathway. (wikipedia.org)
  • The catalytic efficiency (i.e., the ratio between maximal velocity and Michaelis-Menten constant) of the AEA membrane transporter (AMT) is almost doubled compared with control cells, demonstrate that, among the proteins of the "endocannabinoid system," only CB1 and AMT critically depend on membrane cholesterol content, an observation that may have important implications for the role of CB1 in protecting nerve cells against (endo)cannabinoid-induced apoptosis. (wikipedia.org)
  • membrane
  • Src tyrosine kinases, Galpha subunits, and H-Ras share a common membrane-anchored scaffolding protein, caveolin. (wikipedia.org)
  • In order to be active, steroid hormones must free themselves from their blood-solubilizing proteins and either bind to extracellular receptors, or passively cross the cell membrane and bind to nuclear receptors. (wikipedia.org)
  • One study has found that these steroid-carrier complexes are bound by megalin, a membrane receptor, and are then taken into cells via endocytosis. (wikipedia.org)
  • Most neurotransmitters are water-soluble and require transmembrane proteins to transport them across the cell membrane. (wikipedia.org)
  • biosynthesis
  • BACKGROUND: An in vitro steroidogenesis assay using the human adrenocortical carcinoma cell line H295R is being evaluated as a possible screening assay to detect and assess the impact of endocrine-active chemicals (EACs) capable of altering steroid biosynthesis. (thefreelibrary.com)
  • Uptake
  • Although both proteins interact with fatty acids, their relative contributions to the uptake, oxidation, and esterification of straight-chain (palmitic) and branched-chain (phytanic) fatty acids in living cells has not been resolved. (biomedsearch.com)
  • chromosome
  • CAV1 and CAV2 are located next to each other on chromosome 7 and express colocalizing proteins that form a stable hetero-oligomeric complex. (wikipedia.org)
  • transfer protein
  • StAR or STARD1) and lipids like phosphatidylcholine (phosphatidylcholine transfer protein, also called PCTP or STARD2) and have enzymatic activities. (wikipedia.org)
  • hydrophobic
  • There is an increased IL-1β secretion and mevalonate kinase deficiency in MKD is most likely mediated by defective protein prenylation (Prenylation refers to addition of hydrophobic residues to proteins) ] and non-sterol isoprenoids, such as farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP) are coupled to a target protein, which affects the activity and the cellular location. (wikipedia.org)
  • superfamily
  • Other proteins also exist in the human with domains that are members of the START-based superfamily such as PITP, but are not part of the START domain itself. (wikipedia.org)
  • ligand
  • Ligand binding by the START domain in multidomain proteins can also regulate the activities of the other domains, such as the RhoGAP domain, the homeodomain and the thioesterase domain. (wikipedia.org)
  • steroids
  • OBJECTIVES: The goal of this study was to develop a mechanistic computational model of the metabolic network of adrenal steroidogenesis to estimate the synthesis and secretion of adrenal steroids in human H295R cells and their biochemical response to steroidogenesis-disrupting EAC. (thefreelibrary.com)
  • A variety of synthetic steroids and sterols have also been contrived. (wikipedia.org)
  • signaling pathway
  • These transcription factors share the ability to be inhibited and translocated out of the nucleus on phosphorylation by proteins such as Akt/PKB in the PI3K signaling pathway (aside from FOXO6, which may be constitutively nuclear). (wikipedia.org)
  • thioesterase
  • The growing fatty acid chain is carried between these active sites while attached covalently to the phosphopantetheine prosthetic group of an acyl carrier protein (ACP), and is released by the action of a thioesterase (TE) upon reaching a carbon chain length of 16 (palmitic acid). (wikipedia.org)
  • bind
  • Some steroid antagonists: Androgen: cyproterone acetate Progestins: mifepristone, gestrinone Steroid hormones are transported through the blood by being bound to carrier proteins-serum proteins that bind them and increase the hormones' solubility in water. (wikipedia.org)
  • Representatives of the START domain family bind different substances or ligands such as sterols (e.g. (wikipedia.org)
  • StarD1
  • Following the discovery of StAR, 15 START-domain-containing proteins (termed STARD1 through STARD15) were subsequently identified in vertebrates as well as other that are related. (wikipedia.org)
  • functional
  • While loss of functional StAR in the human and the mouse catastrophically reduces steroid production, it does not eliminate all of it, indicating the existence of StAR-independent pathways for steroid generation. (wikipedia.org)
  • subunits
  • The protein links integrin subunits to the tyrosine kinase FYN, an initiating step in coupling integrins to the Ras-ERK pathway and promoting cell cycle progression. (wikipedia.org)