PCK2 and acute kidney injury: To explore the functional role of PTEC RAR signaling after AKI, we crossed Rosa26-LSL-RARaT403X (R26R-DN RAR) mice (33) — which express a Cre-activated, truncated dominant-negative RARa mutation (which inhibits RARa, -b, and -g) — with PEPCK-Cre mice (53), which induce efficient Cre-dependent recombination in PTECs (41).