| 1. |
- Abramczyk, Olga, et al.
(författare)
-
The protein kinase 60S is a free catalytic CK2alpha' subunit and forms an inactive complex with superoxide dismutase SOD1
- 2003
-
Ingår i: Biochemical and Biophysical Research Communications - BBRC. - 0006-291X .- 1090-2104. ; 307:1, s. 31-40
-
Tidskriftsartikel (refereegranskat)abstract
- The 60S ribosomes from Saccharomyces cerevisiae contain a set of acidic P-proteins playing an important role in the ribosome function. Reversible phosphorylation of those proteins is a mechanism regulating translational activity of ribosomes. The key role in regulation of this process is played by specific, second messenger-independent protein kinases. The PK60S kinase was one of the enzymes phosphorylating P-proteins. The enzyme has been purified from yeast and characterised. Pure enzyme has properties similar to those reported for casein kinase type 2. Peptide mass fingerprinting (PMF) has identified the PK60S as a catalytic alpha(') subunit of casein kinase type 2 (CK2alpha(')). Protein kinase activity is inhibited by SOD1 and by highly specific CK2 inhibitor-4,5,6,7-tetrabromo-benzotriazole (TBBt). The possible mechanism of regulation of CK2alpha(') activity in stress conditions, by superoxide dismutase in regulation of 80S-ribosome activity, is discussed.
|
|
| 2. |
- Zielinski, Rafał, et al.
(författare)
-
Inhibition of yeast ribosomal stalk phosphorylation by Cu-Zn superoxide dismutase
- 2002
-
Ingår i: Biochemical and Biophysical Research Communications - BBRC. - 0006-291X .- 1090-2104. ; 296:5, s. 1310-1316
-
Tidskriftsartikel (refereegranskat)abstract
- Reversible phosphorylation of acidic ribosomal proteins of Saccharomyces cerevisiae is an important mechanism, regulating the number of active ribosomes. The key role in regulation of this process is played by specific, second messenger-independent protein kinases. A new protein-inhibitor regulating activity of PK60S kinase has been purified from yeast extracts and characterised. Peptide mass fingerprinting (PMF) and amino-acid sequence analysis by Post Source Decay (PSD) have identified the inhibitor as a Cu-Zn superoxide dismutase (SOD). Inhibition by SOD is competitive with respect to protein substrates-P proteins and 80S ribosome-with K(i) values of 3.7 microM for P2A protein and 0.6 microM for 80S ribosomes. A close correlation was found between the state of phosphorylation of P proteins in diauxic shift and logarithmic growth yeast cells and activity of SOD. The possible mechanism of regulation of PK60S activity, and participation of SOD protein in regulation of 80S-ribosome activity in stress conditions, is discussed.
|
|
