Activation of ERK, JNK, Akt, and G-protein coupled signaling by hybrid angiotensin II AT1/bradykinin B2 receptors expressed in HEK-293 cells

Bradykinin (BK) and angiotensin 11 (AngII) often have opposite roles in cardiovascular diseases. Our aim here was to construct hybrid receptors which bind AngII but signal as BK. Various sequences of the intracellular face of the AngII type I receptor, AT1R, were replaced with corresponding sequences from the bradykinin 132 receptor (BKB2R). The hybrids demonstrated a number of signaling characteristics of the BKB2R. For example, the hybrids demonstrated BK as opposed to AngII like phosphorylation of Akt and JNK. The hybrids containing the BKB2R intracellular loop 2 (IC2) displayed minimal G-protein, G alpha i/G alpha q, linked signaling. Computer based molecular models suggested that Ser-Met-Gly from the IC2 of the BKB2R is detrimental for the G alpha i/G alpha q coupled functions of this hybrid. The return of Lys-Ser-Arg of the AT1R to this hybrid led to almost full recovery of G alpha i and G alpha q activation. The design and production of AT1/BKB2 hybrid receptors is a potential approach in the treatment of hypertension related diseases where the presence of AngII, its AT1 receptor and the consequent signal transduction has proven detrimental.