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

Figure 1

PI-3K activity with β-AR stimulation. HEK 293 cells were transfected with 𝛽₁-AR or 𝛽₂-AR. Forty-eight hours after transfection, cells were stimulated with 1 μM isoproterenol for the indicated times. PI-3K activity was determined by the level of [³²𝑃]-PI produced by the stimulation of 𝛽₁-AR (□) or 𝛽₂-AR (■) expressing cells. Top panel is a representative autoradiograph of TLC separation (𝑛=4-5). Data from these experiments is quantitated in the bottom panel as described in Section 2 . ^∗𝑃<.05 versus 0 minute.