Fig. 1.

Identification of a putative novel motif in GIV (amino acid 1623–1870) responsible for the preferential binding to GDP·Gαi3. (A) The indicated in vitro translated ³⁵S-Met labeled GIV constructs were incubated with approximately 15 μg GST–Gαi3 or GST preloaded with GDP or GDP·AlF₄⁻ immobilized on glutathione beads. Bound proteins were analyzed by autoradiography, and equal loading of GST proteins was confirmed by protein staining (data not shown). (B) A phylogenetically conserved sequence in the C terminus of GIV (amino acid 1678–1694, “GEF motif”) shows similarity to the synthetic peptide KB-752. Sequences obtained from the accession numbers (Fig. S1) were aligned using Clustal W. Conserved residues are shaded in black, similar residues in gray.