PKC isoform-specific targeting of the phosphorylation site Serine191 in the GIRK4 subunit induces receptor-dependent modulation of GIRK channel activity

G Protein activated inwardly rectifying K+ (GIRK) channels are inhibited during stimulation of Gq Protein-coupled receptors (GqPCRs) by depletion of phosphatidyl-4,5-bisphosphate (PIP2) and/or channel phosphorylation by proteinkinase C (PKC). Receptor-specific effects of Gq signaling pathways on GIRK channel activity comprise the activation of different PKC isoforms that target distinct phosphorylation sites within the GIRK4 subunit. The serine residue S191 in the GIRK4 subunit is an important p