Fig. 6. Model for Pelle-mediated feedback in the dorsoventral signal transduction pathway. Control is shown as passing from each protein in the cascade in a linear fashion, although it is probable that all components are present in a large signaling complex (Edwards et al., 1997; Shen and Manley, 1998; Yang and Steward, 1997). Not all components that may be acting in this cascade have been included in this diagram (Grosshans et al., 1999; Zapata et al., 2000).