Peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1 alpha (PGC-1 alpha) and PGC-1 beta are two members of the PGC-1 family and important regulators of mitochondrial metabolism. They are expressed at high levels in heart and skeletal muscle and can induce mitochondrial biogenesis and oxidative capacity. PGC-1 alpha and PGC-1 beta regulate DNA-binding transcription factors, such as estrogen-related receptors (ERRS). ERR beta and ERR gamma are orphan nuclear receptors that act both downstream and parallel to PGC-1 coactivators to control the expression of a broad set of genes important for energy homeostasis.PGC-1/ERR-induced regulator in muscle 1 (Perm1) is a downstream effector of PGC-1 and ERRs [], regulating muscle-specific pathways important for energy metabolism and contractile function. Perm1 does not function as a classical coactivator, but has been suggested to act by regulating signalling pathways in a tissue-selective manner to enable PGC-1/ERRs to induce specific sets of genes. It has been shown that Perm1 is also required for the efficient expression of the glucose transporter Glut4, thus, it may affect glucose uptake, and of the mitochondrial creatine kinase Ckmt2 [].
