By SDS-PAGE and peptide mass fingerprinting, Ishitani et al. (2003) characterized human embryonic kidney cell nuclear proteins that interacted with purified AF-1 of AR. Proteins that interacted with AF-1 included nuclear RNA-binding protein NRB54 (NONO; 300084 ), polypyrimidine tract-binding protein-associated splicing factor (PSF, or SFPQ; 605199 ), paraspeckle protein-1 (PSP1, or PSPC1; 612408 ), and PSP2 (RBM14; 612409 ), which are assumed to be involved in pre-mRNA processing. Binding of NRB54 to AF-1 was ligand dependent, and AF-1 function was potentiated by NRB54.
The receptor is activated by mineralocorticoids such as aldosterone and its precursor deoxycorticosterone as well as glucocorticoids , like cortisol . In intact animals, the mineralocorticoid receptor is "protected" from glucocorticoids by co-localization of an enzyme, Corticosteroid 11-beta-dehydrogenase isozyme 2 (. 11β-hydroxysteroid dehydrogenase 2; 11β-HSD2), that converts cortisol to inactive cortisone. It also responds to some progestins . Spironolactone and eplerenone are steroidal MR antagonists of the spirolactone group.
(MWt 44 KDa), (AAG, AGP, Orosomucoid, ORM ) has a normal plasma concentration between - g/dl (1-3% plasma protein). It is negatively charged at physiological pH and interacts mainly with basic drugs, including beta-adrenergic-receptor blockers, antidepressants, neuroleptics and local anaesthetics. There is a crystal structure in the PDB 3BX6 the branched, partly hydrophobic, and partly acidic cavity, together with the presumably flexible loop 1 and the two sugar side chains at its entrance, explains the diverse ligand spectrum of AGP, which is known to vary with changes in glycosylation pattern. The crystal structure of the A variant of human alpha1-acid glycoprotein and amitriptyline complex 3APV has been recently de[posited in the PDB and highlights pi-stacking interactions are important in ligand binding.