This application is for a contribution towards the cost of a FASEB Summer Research Conference to be held at Saxton's River, VT, June 26 - July 1, 1993. It will be the second FASEB meeting on ras-related small GTP-binding proteins, the first was held in Aug 1991 and was agreed to be an unqualified success. This area of research has continued to flourish and as then, the aim of this second meeting is to bring together scientists and physicians working on different biological problems where small GTP-binding proteins are known or are suspected to play a regulatory role. A remarkably diverse set of biological systems are regulated by ras-related proteins: p2lras and its close relatives control cell growth and differentiation and in addition to the biochemical evidence for their role as transducers of signals from activated receptors, the genetic analysis of lower organisms has pinpointed their importance in developmental control. Small GTP-binding proteins related to p2lrho control aspects of cell polarity and morphology, processes intimately coupled to the organization of polymerized actin. This group of proteins seems to have taken on highly specialized roles in terminally differentiated cells, for example rac controls superoxide production in phagocytes while rho regulates chemotaxis in neutrophils and the aggregation of platelets. A large group of small GTP-binding proteins, rabs and ARFs, regulate the trafficking and assembly of intracellular vesicles. This area has grown dramatically over the last couple of years with the identification of over thirty individual proteins and the introduction of semi-in vitro assays to determine their contribution to transport through the exocytic and endocytic compartments. Although there was close to overkill in GTP-binding protein meetings in l99l, very few meetings covering this area have been staged in 1992. With such diverse areas of modern cell biology such as growth, development, polarity, morphogenesis and intracellular trafficking converging on one superfamily of proteins, we feel that a 1993 meeting is both timely and important for the continued development of this field.