RPS6KB1 and keratoconus: Similarly, obese KC mice showed a marked increase in mTORC1 activity, as judged by the enhancement in the phosphorylation of the ribosomal protein S6 at Ser235/236, a direct target of p70S6 kinase (p70S6K) which in turn, is activated by mTORC1 (Fig. 3a, quantification in Fig. 3b).