Chapter 4 Signal Transduction by GTP Binding Proteins during Leukocyte Activation: Phagocytic Cells

Abstract

Publisher Summary This chapter describes the current knowledge of guanosine-5'-triphosphate (GTP) binding protein composition and function in the neutrophil, placing this information in the context of what is understood about GTP binding protein-mediated signal transduction in more well-defined systems. It points out areas in which more biochemical and mechanistic detail is required for validating current hypotheses about GTP binding protein function in the neutrophil. The GTP binding protein-catalyzed interaction can result in a signal being propagated and amplified (as in the case of the “classical” receptor-coupled GTP binding proteins), a process being spatially directed (as by the elongation factors involved in protein synthesis), or, in other events, requiring reversible interaction of macromolecules. The basic catalytic cycle can be divided into four stages. The process of leukocyte activation involves a variety of cellular responses, including cell shape changes, aggregation, phagocytosis, granule enzyme secretion, and stimulation of the respiratory burst, which generates superoxide anion.