We have quantitatively investigated specificities in activating G-protein subtype by bovine and squid rhodopsins to examine whether or not the phototransduction cascade in each of the photoreceptor cells is determined by the colocalization of a large amount of G-protein subtype (Gt or Gq). In contrast to the efficient activation of respective Gt and Gq, bovine and squid rhodopsins scarcely activated G-protein counterparts. Exchange of α- and βγ-subunits of Gt and Gq indicated the critical role of the α-subunit in specific binding to respective rhodopsins. Thus the specific recognition of G-protein subtype by each rhodopsin is a major mechanism in determining the phototransduction cascade. Copyright (C) 1998 Federation of European Biochemical Societies.
Terakita, A., Yamashita, T., Tachibanaki, S., & Shichida, Y. (1998). Selective activation of G-protein subtypes by vertebrate and invertebrate rhodopsins. FEBS Letters, 439(1–2), 110–114. https://doi.org/10.1016/S0014-5793(98)01340-4