Protein Phosphatase-1 Activates CDK9 by Dephosphorylating Ser175. - Ammosova, Tatiana; Obukhov, Yuri; Kotelkin, Alexander; Breuer, Denitra; Beullens, Monique; Gordeuk, Victor R.; Bollen, Mathieu; Nekhai, Sergei (PLoS ONE, 2011)