Determinants Present in the Receptor Carboxy Tail Are Responsible for Differences in Subtype-Specific Coupling of 𝛽-Adrenergic Receptors to Phosphoinositide 3-Kinase

Figure 4

GRK2 carboxy-terminal domain reduced PI-3K recruitment to membrane fractions in response to β-AR stimulation. HEK 293 cells were cotransfected with ct-GRK-2 and β-AR subtypes. Forty-eight hours after the transfection, cells were stimulated with 1 μM isoproterenol for 5 minutes. PI3-kinase recruitment to particulate fractions decreased with cells expressing either 𝛽₁-AR (□) or 𝛽₂-AR (■) in presence of cotransfected ct-GRK2. Top panel is a representative immunoblot of the experiments (𝑛=4-6). Data from these experiments is quantitated in the bottom panel as described in Section 2. ^∗𝑃<.05 versus 0 minute.