It is by no means a revelation that proteins are not uniformly distributed throughout the cell. As a result, the idea that protein molecules, because of the specificity with which they can engage in interactions with other proteins, may be aimedvia these interactionsat a restricted target, is a fundamental one in contemporary molecular life sciences. The target may be variously c- ceived as a specific molecule, a group of molecules, a structure, or a more generic type of intracellular environment. Because the concept of protein targeting is intuitive rather than expl- itly defined, it has been variously used by different groups of researchers in cell biology, biochemistry, and molecular biology. For those working in the field of intracellular signaling, an influential introduction to the topic was the seminal article by Hubbard & Cohen (TIBS [1993] 18, 172177), which was based on the work of Cohen's laboratory on protein phosphatases. Sub- quently, the ideas that they discussed have been further developed and extended by many workers to other key intermediaries in intracellular sign- ing, including protein kinases and a great variety of modulator and adaptor proteins.

Zusammenfassung
Sub- quently, the ideas that they discussed have been further developed and extended by many workers to other key intermediaries in intracellular sign- ing, including protein kinases and a great variety of modulator and adaptor proteins.

Inhalt
Surface Plasmon Resonance.- Microcalorimetry of Protein-Protein Interactions.- Partitioning of Proteins in Triton X-114.- Co-Immunoprecipitation.- Overlay, Ligand Blotting, and Band-Shift Techniques to Study Kinase Anchoring.- Size-Exclusion Chromatography.- Overlay and Bead Assay.- Use of GST-Fusion and Related Constructs for the Identification of Interacting Proteins.- Molecular Genetic Approaches I.- Molecular Genetic Approaches II.- Molecular Genetic Approaches III.- Molecular Genetic Approaches IV.- Use of Synthetic Peptides in the Dissection of Protein-Targeting Interactions.- SH2 and SH3 Domains.- PH Domain of Serine-Threonine Protein Kinase B (RAC-PKB).- Membrane Targeting via Protein N-Myristoylation.- Membrane Targeting via Protein Palmitoylation.- Agonist-Mediated Turnover of G-Protein ?-Subunit Palmitoyl Groups.- Membrane Targeting via Protein Prenylation.- Nuclear Protein Import in a Permeabilized Cell Assay.- Clathrin-Coated Vesicles and Targeting.- Analysis of the Sorting of Secretory Proteins to the Regulated Secretory Pathway.