GFPT1 and idiopathic pulmonary fibrosis: In addition, spatial cluster maps of GFPT1 (GFAT; the rate-limiting step in the HBP) (49), OGT and MGEA5 (gene encoding OGA) showed more expression in the selected IPF fibroblast and myofibroblast cell populations that had increased collagen expression (COL1A1 and COL3A1) and other fibrotic markers (ACTA2 and TGFB1) compared to the non-IPF controls (Figure 1C).