RPS6KB1 and fetal growth restriction: Ribosomal protein S6 kinase 1 (S6K1) is under the control of mTORC1 signaling.23 By activating the mTORC1/S6K1 pathway, checkpoint kinase 1 stimulates myocardial regeneration.3 Positive regulation of mTORC1 is required for normal fetal growth and development,24 and decreased expression of the RPs RPL26 and RPS10 in the placenta leads to intrauterine growth restriction in pregnant women.