Figure 2.

Weak stimulation of PLC suffices to activate phosphorylation by PKC strongly. (A) Schematic of real-time phosphorylation measurement by the CKAR and AKAP-CKAR probes. FRET at rest is reduced by the conformational change resulting from CKAR phosphorylation. CKAR is cytosolic, whereas AKAP-CKAR is located at the plasma membrane (see Fig. S1). (B) Cell expressing CKAR and M₁R. Representative recording of changes in FRETr in response to 100 µM UTP and 10 µM Oxo-M. (C) Cell expressing AKAP-CKAR and M₁R. Representative recording of the FRETr response to 100 µM UTP and 10 µM Oxo-M. (D) Summary of experiments as in B and C. There are no significant differences between responses to UTP and Oxo-M of CKAR (UTP, n = 8; Oxo-M, n = 5) and AKAP-CKAR (UTP, n = 7; Oxo-M, n = 6).