Microcompartmentation refers to nonhomogeneous distribution of solutes in compartments of cells or associated structures without intervening membranal barriers. Such variations in concentration of ions, metabolites, intracellular messengers, and nutrients can introduce significant heterogeneity in subcellular function and regulation. The current focus on biological examples of microcompartmentation provides ample evidence for its importance and the role of physical structure in determining local chemical environments. The examples present in the different chapters include microcompartmentation of Ca2+,H+,ATP. ADP, O2, glycolytic intermediates, fatty acids, amino acids, and nucleic acid precursors. In reviewing these systems, the authors provide a useful resource for experimental approaches to study microcompartmentation and provide the basis for future studies of its role in regulation of cell functions.
1. On the Internal Environment of Animal Cells 2. Functional Compartmentation of Carbohydrate Metabolism 3. Mitochondrial Distribution and 02 Gradients in Mammalian Cells 4. Involvement of Microcompartmentation in the Regulation of Cell Proliferation 5. Diffusion and Ultrastructural Adaptive Responses in Ectotherms 6. Microcompartmentation of Metabolite Transport in Mitochondria 7. The Membranes Involved in Proton-Mediated Free-Energy Transduction: Thermodynamic Implications of their Physical Structure 8. Microcompartmentation of DNA Precursors 9. Function of Ambiquitous Proteins in a Heterogeneous Medium 10. Microzonation of ATP and pH in the Aqueous Cytoplasm of Mammalian Cells 11. Hyrdrogen and Calcium Ion Diffusion in Axoplasm 12. Fluorescence Digital Imaging Microscopy � Spatial Distribution of Ca2+ and H+ in single Cells