Expression of GIRK (Kir3.1/Kir3.4) channels in mouse fibroblast cells with and without β1 integrins

G protein‐activated K⁺ channel (GIRK) subunits possess a conserved extracellular integrin‐binding motif (RGD) and bind directly to β1 integrins. We expressed GIRK1/GIRK4 channels labeled with green fluorescent protein in fibroblast cell lines expressing or lacking β1 integrins. Neither plasma membrane localization nor agonist‐evoked GIRK currents were affected by the absence of β1 integrins or by incubation with externally applied RGD‐containing peptide. Mutation of the aspartate (D) of RGD impaired currents, GIRK glycosylation, and membrane localization, but the interaction with β1 integrins remained intact. Thus, β1 integrins are not essential for functional GIRK expression; and the GIRK‐integrin interactions involve structural elements other than the RGD motif.