Fig. 7.
Proposed model of Rho-regulated Wash maintenance of egg chamber cyto-architecture. (A) In nurse cells, Rho activates Wash nucleation of branched actin filaments (left) providing structural integrity for nurse cells and ring canals. In the oocyte, active Rho inhibits SpirD (right), freeing Capu, SpirC and Wash to crosslink/bundle cortical microfilaments and MTs, and preventing premature ooplasmic streaming (see illustration in B). Upon an unknown signaling event during stage 10b, SpirD is released from RhoGTP inhibition, binds to Capu, SpirC and Wash, and inhibits their crosslinking/bundling activity. This initiates the formation of subcortical MT arrays (B′), leading to ooplasmic streaming. (B,B′) Illustration of signaling events depicted in A.