Figure 5.

N-end modification and ubiquitylation of the Gγ₂ subunit. Depicted above is the crystal structure (IGP2) for the Gα_i1, β₁, γ₂ heterotrimer, with the N terminus of α and C terminus of γ oriented toward the plasma membrane (25). Structural figure includes amino acids 8–61 of the γ₂ subunit (amino acids 1–71) with the remainder of residues absent because of disordered structure. Lysine residues within γ₂ are represented in red ball and stick format (with the exception of K64 and K65). The N terminus of γ₂, the site of posttranslational modification, extends toward the interior of the cell, whereas the sites of ubiquitylation (indicated by black stars) are more closely oriented toward the plasma membrane.