title: Soluble phorbol ester binding sites in cytosol of chick liver and brain--activation by phosphatidylserine.
abstract: The cytosol from chick liver and brain contains specific high affinity binding sites for the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The soluble TPA binding sites are measurable by a filter assay. One finds in liver and brain 0.1 and 3.1 pmol, respectively, of cytoplasmic TPA binding sites/mg protein. The dissociation constants of the respective complexes are in the range of 10(-8) M. Biologically inactive phorbol esters do not compete with TPA for the binding sites. The number of TPA binding sites in cytosol can be increased 3- to 4-fold by the addition of phosphatidylserine. This phospholipid, however, does not stimulate the TPA binding capacity of chick erythrocytes or of the particulate fraction from chick brain.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D002645:Chickens; D003600:Cytosol / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D010704:Phorbols / Q000378:metabolism*; D010718:Phosphatidylserines / Q000494:pharmacology*; D011493:Protein Kinase C; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D011955:Receptors, Drug; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D010704:Phorbols; D010718:Phosphatidylserines; D011956:Receptors, Cell Surface; D011955:Receptors, Drug; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate