Effect of starvation on the endocytic pathway in Dictyostelium cells.
Dictyostelium discoideum amoebae have been used extensively to study the structure and dynamics of the endocytic pathway. Here, we show that while the general structure of the endocytic pathway is maintained in starved cells, its dynamics rapidly slow down. In addition, analysis of apm3 and lvsB mutants reveals that the functional organization of the endocytic pathway is profoundly modified upon starvation. Indeed, in these mutant cells, some of the defects observed in rich medium persist in starved cells, notably an abnormally slow transfer of endocytosed material between endocytic compartments. Other parameters, such as endocytosis of the fluid phase or the rate of fusion of postlysosomes to the cell surface, vary dramatically upon starvation. Studying the endocytic pathway in starved cells can provide a different perspective, allowing the primary (invariant) defects resulting from specific mutations to be distinguished from their secondary (conditional) consequences.
Smith
Ewan W
EW
Dept. for Cell Physiology and Metabolism, Centre Medical Universitaire, Geneva Faculty of Medicine, 1211 Geneva 4, Switzerland.
Lima
Wanessa C
WC
Charette
Steve J
SJ
Cosson
Pierre
P
D033983:Adaptor Protein Complex mu Subunits / Q000235:genetics; D003470:Culture Media / Q000494:pharmacology; D004023:Dictyostelium / Q000187:drug effects / Q000502:physiology*; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology; D005508:Food Deprivation; D007700:Kinetics; D008247:Lysosomes / Q000187:drug effects / Q000502:physiology; D008561:Membrane Fusion / Q000187:drug effects / Q000502:physiology; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology; D010873:Pinocytosis / Q000187:drug effects / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics; D013312:Stress, Physiological / Q000502:physiology*; D022161:Transport Vesicles / Q000187:drug effects / Q000502:physiology; D033921:Vesicular Transport Proteins / Q000235:genetics
D033983:Adaptor Protein Complex mu Subunits; D003470:Culture Media; D015800:Protozoan Proteins; D033921:Vesicular Transport Proteins