The ribosomal prolyl-hydroxylase OGFOD1 decreases during cardiac differentiation and modulates translation and splicing

The mechanisms regulating translation and splicing are not well understood. We provide insight into a new regulator of translation, 2-oxoglutarate and iron dependent oxygenase domain–containing protein 1 (OGFOD1), which is a prolyl-hydroxylase that catalyzes the posttranslational hydroxylation of Pro62 in the small ribosomal protein S23. We show that deletion of OGFOD1 in an in vitro model of human cardiomyocytes decreases translation of specific proteins (e.g., RNA-binding proteins) and alters splicing. RNA-Seq showed poor correlation between changes in mRNA and protein synthesis, suggesting that posttranscriptional regulation was the primary cause for the observed differences. We found that loss of OGFOD1 and the resultant alterations in protein translation modulated the cardiac proteome, shifting it toward higher protein amounts of sarcomeric proteins, such as cardiac troponins, titin, and cardiac myosin-binding protein C. Furthermore, we found a decrease of OGFOD1 during cardiomyocyte differentiation. These results suggest that loss of OGFOD1 modulates protein translation and splicing, thereby leading to alterations in the cardiac proteome, and highlight the role of altered translation and splicing in regulating the proteome.