《细胞骨架》.ppt

B. Techniques for studying the cytoskeleton 2. Microfilament, MF A. MFs are made of actin and involved in cell motility. B. MF assembly and disassembly C. Specific drugs affect polymer dynamics D. Actin-binding proteins E. Functions of MFs (1) Maintain cell’s shape and enforce PM (2) Cell migration (Fibroblast et al) (3) Microvillus: Support the projecting membrane of intestinal epithelial cells (4) Stress fibers (5) Contractile ring: For cytokinesis (6) Muscle contraction Sarcomere Proteins play important roles in muscle contraction Thick and thin filaments sliding model Excitation-contraction coupling process 3.Microtubule, MT Tubulin heterodimers are the protein building blocks of MTs Arrangement of protofilaments in singlet, double, and triplet MTs B. MTs assemble from microtubule-organizing centers (MTOCs) Basal body structure C. Characteristics of MT assembly Why the centrosome can act as MTOC Experiments supporting that centrosome is the MTOC MT are nucleated by a protein complex containing ?-tubulin Drugs affect the assembly of MTs Microtuble-associated proteins (MAPs) Organization of MT bundles by MAPs . Spacing of MTs depends on MAPs 5. Functions of MTs 1. Maintain cell shape Intermediate filaments, IFs IFs are the most abundant and stable components of the cytoskeleton 3. Function of IFs: Confer mechanical strength on tissues Summary: Cytoskeletal functions Fig.?10-31?Microtubule dynamics in a living cell.????A fibroblast was injected with tubulin that had been covalently linked to rhodamine, so that approximately 1 tubulin subunit in 10 in the cell was labeled with a fluorescent dye. Note, for example, that microtubule #1 first grows and then shrinks rapidly, whereas microtubule #4 grows continuously. (P.J. Sammak et al., Nature 332: 724-736) 细胞内物质运输 Motor Protein 1. Kinesin Family 2. Dynein Family 染色体运动 Figure?16-84?Electron micrographs of an insect flight muscle viewed in cross-section.????The myosin and actin fil