The AT1 receptor is important for blood pressure. The signaling mechanisms of the receptor is of particular interest in order to understand the overall effect of angiotensin 11 binding to the receptor. The proposal herein addresses: Specific Aim 1: To investigate the importance of the five tyrosines located on the carboxyl tail of the AT receptor for G-protein coupling and/or activation. Hypothesis - The tyrosines on the carboxyl tail of the AT1 receptor are necessary for -protein coupling and/or activation. Specific Aim 2: To investigate the significance of the five tyrosines located on the carboxyl tail of the AT1 receptor for tyrosine kinase activity. Hypothesis - The mutation of the five tyrosines on the carboxyl tail of the AT receptor does not disrupt the coupling of the receptor to intracellular tyrosine kinase proteins.