Diverse β subunits of heterotrimeric G proteins are present in thyroid plasma membranes

► In Nthy-ori 3-1 cells plasma membranes Gβ1 to Gβ5 isoforms of G protein are present. ► In thyroids plasma membranes the Gβ1, Gβ2, Gβ4 and Gβ5 but not Gβ3 were found. ► Competition studies revealed that the Gβ2 is the principal thyroidal Gβ isoform. ► It suggests that Gβ2 cooperates with Gαs during physiological thyroid stimulation.