Biopolymers and cell. 2005; 21 (1): 42 - 47

Effect of point mutations of regulatory aminoacids residues and N- and C-terminal deletions of S6K1 i S6K2 on kinase activity

T. I. Valovka, I. T. Gout, V. V. Filonenko

The family of ribosomal protein S6 kinases includes two forms S6K1 and S6K2 that share high level of structural homology towards catalytic domains. Existence of homological phosphorylation sites suggests the functioning of similar mechanisms of the kinase activation. Using site-directed mutagenesis and N-, C-terminal deleting of S6K it has been demonstrated that phosphorylation of Thr412 and Thr401 are necessary for the full activation of S61 and S62 correspondently. Different sensitivity of S6K to the inhibitory actions of rapamicine relates to the structure of C-terminal S6K regions that exhibits low homology.

Key words: ribosomal protein S6, S6K1 and S6K2, site-directed mutagenesis.