Fig. 7. Dynein, dynactin and membrane compartment markers after phase partitioning analysis of density gradient fractions. Density gradient fractions from CCH-stimulated acini were analyzed by partitioning in an aqueous dextran-polyethyleneglycol two-phase system. Gradient fractions 1 and P were analyzed individually; other fractions were pooled as follows: 4+5, 7+8, 9+10, 11+12. Modal positions of compartments are designated by a-o. Compartments j and m are proposed to contain secretory transport vesicles and related compartments [recruitable secretory vesicles (rsv) and immature secretory vesicles (isv)]. Other compartment designations are discussed in detail by Qian et al. (Qian et al., 2002). (a) Basal-lateral recycling endosome; (e) Basal-lateral sorting endosome; (ß-d,f,h,i) Specialized TGN microdomains; (g) Golgi complex; (k) Secretory vesicle membrane fragments; (l,o) Pre-lysosomes; (n) Lysosomes. Similar results were obtained in a second analysis with a different phase system composition.