Novel signaling pathway through the beta-adrenergic receptor.

beta -Adrenergic receptors transduce signals through the heterotrimeric G protein Galphas to regulate cardiac function. Recently, it has been discovered that Galphas could directly stimulate the Src family tyrosine kinase activity. This novel signaling pathway provides insights into the cAMP-PKA-independent signaling mechanisms used by beta -adrenergic receptors to regulate apoptosis, receptor desensitization, and other physiological functions.