An intact helical domain is required for Gα 14 to stimulate phospholipase Cβ

Background Stimulation of phospholipase Cβ (PLCβ) by the activated α-subunit of Gq (Gαq) constitutes a major signaling pathway for cellular regulation, and structural studies have recently revealed the molecular interactions between PLCβ and Gαq. Yet, most of the PLCβ-interacting residues identified on Gαq are not unique to members of the Gαq family. Molecular modeling predicts that the core PLCβ-interacting residues located on the switch regions of Gαq are similarly positioned in Gαz which does not stimulate PLCβ. Using wild-type and constitutively active chimeras constructed between Gαz and Gα14, a member of the Gαq family, we examined if the PLCβ-interacting residues identified in Gαq are indeed essential.