AKT1 and Hyperkeratosis: The skin of Akt1 null mice models and Akt1 knockdown organotypic cultures display hyperkeratosis with reduced cornified envelope strength and reduced filaggrin expression and processing.17, 53, 54 Activation of Akt1 also results in hyperkeratosis and altered filaggrin expression,17, 54 demonstrating that normal Akt activity levels are required for correct filaggrin processing and hence epidermal barrier function.