... to the development of novel ras inhibitory, antiatherogenic and antioncogenicstrategies.ACKNOWLEDGEMENTSDr Johan van Es (University of Utrecht, Department of Immunology,Utrecht, the Netherlands) ... acts either upstream, via aninteraction with Drk (the Drosophila equivalent of the human adaptor protein Grb2) and the GTPase-activatingprotein GAP1 [2], or downstream of ras at the level of Raf/MAP ... [9]. Differences between individual sprouty family members are greatest in the N-terminal part of the proteins, suggesting that this part of the protein may convey specificity to the activity of the Correspondence...