PPM1K and cystic fibrosis: Mechanistically, periostin upregulated nucleosome assembly protein 1-like 2 (NAP1L2) to recruit SIRT3 to deacetylate H3K27ac on the promoters of the branched-chain amino acids (BCAAs) catabolism-related enzymes BCAT2 and PP2CM, leading to overproduction of BCAAs in CF and subsequent cardiac fibrosis.