title: A macromolecular structure favouring microtubule assembly in NGF-differentiated pheochromocytoma cells (PC12).
abstract: Cellular extracts derived from pheochromocytoma cells (PC12-) inhibit the assembly of calf brain tubulin, while those derived from nerve growth factor-differentiated cells (PC12+) do not display this effect. Incubation with RNase abolishes the inhibition by PC12- extracts and reveals the presence of an activating effect exerted by PC12+ extracts. Activation of microtubule assembly is enhanced when extracts are prepared from PC12+ cells exposed for 1 day to 1.0 microM taxol and is abolished when PC12+ extracts are: (a) prepared from cells incubated for 1 day with 1 microM colchicine, (b) treated with the non-ionic detergent Nonidet P-40 or (c) centrifuged at 100 000 g instead of 80 000 g. 2D gel electrophoresis of the proteins of the 100 000 g pellet responsible for the activating effect (referred to as 100 K g pellet) reveals the presence of 100 K, 88 K and 32 K proteins which are markedly enriched in PC12+ extracts. The 88 K protein is further enriched in taxol-treated cells and markedly reduced in the same cells incubated with colchicine. A correlation between the differential protein composition of the 100 K g pellets and their effect on microtubule formation is postulated.
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000032:analysis / Q000473:pathology*; D006801:Humans; D007700:Kinetics; D008870:Microtubules / Q000648:ultrastructure*; D008970:Molecular Weight; D009414:Nerve Growth Factors / Q000494:pharmacology*; D010673:Pheochromocytoma / Q000032:analysis / Q000473:pathology*; D011506:Proteins / Q000032:analysis
chemical_list: D009414:Nerve Growth Factors; D011506:Proteins