Biochemical characterization of 60S acidic ribosomal P proteins from porcine liver and the inhibition of their immunocomplex formation with sera from systemic lupus erythematosus (SLE) patients by glycyrrhizin in vitro.
The three casein kinase II (CK-II) phosphate acceptors (p35, p17 and p15) in the Superdex CK-II fraction prepared from a 1.5 M NaCl extract of porcine liver were selectively purified by glycyrrhizin (GL)-affinity column chromatography (HPLC) as a heterocomplex associated with CK-II. Determination of the N-terminal amino acid sequences and immunological tests confirmed that these three CK-II phosphate acceptors belong to the family of 60S acidic ribosomal proteins (P0, P1 and P2). Three polyphenol-containing anti-oxidant compounds [catechin, epigallocatechin gallate (EGCG) and quercetin] inhibited CK-II activity (phosphorylation of these ribosomal P proteins) in a dose-dependent manner in vitro. Quercetin (ID50 = approx. 50 nM) was found to be an effective CK-II inhibitor. In contrast, CK-II activity was significantly stimulated by lower doses (0.3-3 microl) of GL, but was inhibited at high doses above 30 microM. As expected, GL at high doses above 200 microM inhibited the immunocomplex formation of 60S acidic ribosomal P proteins with their specific antibodies in the sera from patients with systemic lupus erythematosus (SLE). These results suggest that (i) a GL-affinity column is useful for effective purification of 60S acidic ribosomal P proteins from various mammalian cells as a heterocomplex associated with CK-II; and (ii) a relative high dose of GL may prevent the immunocomplex formation of 60S acidic ribosomal P proteins with their specific antibodies in the sera of SLE patients.
Maekawa
T
T
Laboratory of Genetical Biochemistry, School of Allied Health Sciences, Kitasato Unsiversity, Sagamihara, Japan.
Kosuge
S
S
Karino
A
A
Okano
T
T
Ito
J
J
Munakata
H
H
Ohtsuki
K
K
D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D000936:Antigen-Antibody Complex / Q000097:blood*; D000975:Antioxidants / Q000494:pharmacology; D001323:Autoantibodies / Q000276:immunology / Q000378:metabolism; D047390:Casein Kinase II; D002846:Chromatography, Affinity; D019695:Glycyrrhizic Acid / Q000494:pharmacology*; D006801:Humans; D008099:Liver / Q000737:chemistry* / Q000201:enzymology; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000276:immunology; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000097:blood / Q000276:immunology / Q000302:isolation & purification*; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000037:antagonists & inhibitors / Q000097:blood / Q000276:immunology / Q000302:isolation & purification*; D013552:Swine
D000936:Antigen-Antibody Complex; D000975:Antioxidants; D001323:Autoantibodies; D010750:Phosphoproteins; D012269:Ribosomal Proteins; C031937:phosphoprotein P2, ribosomal; C035690:ribosomal phosphoprotein P1; C054675:ribosomal protein P0; D019695:Glycyrrhizic Acid; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases