[Characteristics of endoribonuclease activity of proteasomes from K562 cells. I. Dependence of RNAase activity of proteasome and alph-RNP on conditions of endonucleolysis reaction].
Proteosomes from human proerythroleukaemic cell line K562 are found to degrade high molecular weight cytoplasmic RNAs, particularly ribosomal and specific messenger RNA. This activity was observed to be endoribonucleotylic. The induction of differentiation by erythroid pathway in K562 cells invokes augmentation of endonuclease activity in proteasomes. The number of characteristics of this enzymatic activity was investigated. Specificity of endonuclease of these RNPs is shown to be Ca- and Mg-dependent. Dephosphorylation of protein subunits suppresses RNase activity of proteasomes. Endonuclease of proteasomes is thermolabile. The examined activity depends on the secondary structure of substrate RNA. Protein subunits are responsible for ribonuclease activity of proteasomes rather than for low molecular weight RNAs associated with the complex.
Mummenberg
A G
AG
Institute of Cytology RAS, St. Petersburg. agm@mail.cytspb.rssi.ru
Kulichkova
V A
VA
Medvedeva
N D
ND
Penniiaĭnen
V A
VA
Gauze
L N
LN
Konstantinova
I M
IM
D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004722:Endoribonucleases / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D046988:Proteasome Endopeptidase Complex; D012313:RNA / Q000737:chemistry / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D013379:Substrate Specificity
D009097:Multienzyme Complexes; D012261:Ribonucleoproteins; D012313:RNA; D004722:Endoribonucleases; D012260:Ribonucleases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex
Kharacteristiki éndoribonukleaznoĭ aktivnosti proteasom iz kletok linii K562. I. Zavisimost' RNKaznoĭ aktivnosti proteasom i alpha-RNP ot usloviĭ reaktsii éndonukleoliza.