Fig. 7. Modulation of antigen receptor signaling by PKCβ. (A) Model for the PKCβ-mediated inhibition of Btk membrane localization. (B) Schematic representation of the Btk activity requirement for B-cell survival and function. Btk-XLAi (inactivated) represents loss-of-function Btk mutations. Btk-XLAa (activated) represents gain-of-function Btk mutations.