IndraLab

Statements


RPS6KB1 phosphorylated on T444 is kinase-active. 2 / 2
2 |

"from full text - T229 is situated in the catalytic domain of p70S6K, and in addition to T389, its phosphorylation is necessary for full activation of the protein. Residues T421 and S424 are situated in the autoinhibitory/pseudosubstrate domain of the C-terminus, and phosphorylation of these residues is proposed to be one of the early steps of p70S6K activation (2)."

"The initially identified sites of phosphorylation (of RPS6KBP1), S411, S418, T421 and S424 are all flanked by a proline in the +1 position and reside within the putative autoinhibitory domain of Module IV [22]. Peptides which correspond in sequence to this domain inhibit the kinase [51], consistent with the hypothesis that Module IV acts as an autoinhibitory domain. These four residues are hypophosphorylated in quiescent cells, and become hyperphosphorylated in response to serum [23]. Substitution of these S/T-P sites with alanines [23] suppresses activation of the kinase, whilst the corresponding acidic residue replacements raise basal kinase activity [10]."