Biochemical characterization of 60S acidic ribosomal P proteins associated with CK-II from bamboo shoots and potent inhibitors of their phosphorylation in vitro.
Three effective phosphate acceptors (35, 15 and 13 kDa polypeptides) for casein kinase II (CK-II) in the Superdex CK-II fraction prepared from a 0.5 M NaCl extract of bamboo shoots were selectively purified by glycyrrhizin (GL)-affinity column chromatography (HPLC). These three proteins (p35, p15 and p13) were identified as 60S acidic ribosomal P proteins by determination of their partial N-terminal sequences. CK-II was associated with p35 since the GL-affinity fraction was coprecipitated with an anti-serum against Drosophila CK-IIbeta. Moreover, a derivative (oGA) of glycyrrhetinic acid (GA) and several polyphenol-containing anti-oxidative compounds [quercetin, epigallocatechin gallate (EGCG) and two isoflavones, i.e., 3',4',7-trihydroxyisoflavone (3',4',7-THI) and 8-chloro-3',4',5,7-tetrahydroxyisoflavone (8C-3',4',5,7-THI)] inhibited the CK-II-mediated phosphorylation of 60S acidic ribosomal P proteins in vitro. Quercetin was found to be the most effective compound on CK-II activity since its ID50 was approx. 50 nM. These results suggest that (i) GL-affinity column chromatography is useful for the selective purification of 60S acidic ribosomal P proteins as a heterocomplex associated with CK-II from various cell sources; (ii) natural anti-oxidative compounds with polyphenols, but not GL and GA, act as potent CK-II suppressors; and (iii) CK-II mediates the regulation of the physiological functions of 60S acidic ribosomal P proteins in growing plant cells.
Maekawa
T
T
Laboratory of Genetical Biochemistry, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan.
Kosuge
S
S
Sakamoto
S
S
Funayama
S
S
Komiyama
K
K
Ohtsuki
K
K
D047390:Casein Kinase II; D002392:Catechin / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D008970:Molecular Weight; D010766:Phosphorylation; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006109:Poaceae / Q000737:chemistry*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D011794:Quercetin / Q000494:pharmacology
D004791:Enzyme Inhibitors; D010940:Plant Proteins; D002392:Catechin; D011794:Quercetin; D019833:Genistein; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases