G protein complement of SV40-transformed ciliary epithelial cells.

Guanine nucleotide-binding proteins (G proteins) are a family of receptor-coupled signal-transducing proteins that regulate a variety of second-messenger systems and ion channels. The complement of G proteins in SV40-transformed pigmented and nonpigmented ciliary epithelial cells was determined by Western blot analysis utilizing peptide and holoprotein derived antisera to known G protein alpha and beta subunits and cholera toxin catalyzed ADP-ribosylation. The complement of alpha subunits found in both SV40-transformed NPE and PE cells includes Gs alpha and all three members of the Gi alpha family. Neither cell type contains Go alpha or Gz alpha. Both cell lines contain beta 35 and beta 36. Future studies will examine the functional involvement of these G proteins in the regulation of aqueous humor stimulus-secretion coupling.