Figure 4.

Gα₁₂ and Gα₁₃, but not Gα_i, inhibit neurite outgrowth and induce cell rounding. (A) N1E-115 cells were transfected with either a control vector or expression vectors encoding activated Gα₁₂, Gα₁₃, or Gα_i, together with an expression vector encoding β-galactosidase. Cells were cultured in serum-free medium overnight, and morphologies were assessed as described. (B) Analysis of the actin cytoskeleton in Gα₁₂- and Gα₁₃-expressing cells. Rhodamine-phalloidin staining reveals that the cortical cytoskeleton in these cells is completely contracted, forcing the cells to round up. (C) Cells were transfected with Gα₁₂ and Gα₁₃ together with either a control vector or a vector encoding (dominant-negative) N19RhoA. Morphologies were then assessed as in A: Gα₁₂- and Gα₁₃-induced inhibition of neurite outgrowth and cytoskeletal contraction are RhoA dependent.