CDK9 and infectious otitis media: Immunoblot analysis showed induced CDK9 and the inactivation of the cell cycle protein CDKN2A, along with induced phosphorylation of extracellular signal-regulated kinase (ERK), AKT serine/threonine kinase (AKT), and epidermal growth factor receptor (EGFR) in the cerulein- and cerulein-with-AOM–treated mice compared with saline- and AOM-treated mice (Fig 4G).