Figure 11.

Immunolocalization of dynamin A, postlysosomal compartments, the Golgi-complex, and mitochondria by confocal laser scanning microscopy. (A and A′) Anti-vacuolin antibody 221-1-1 was used to stain a postlysosomal compartment that acquires endocytic markers shortly before exocytosis. Single confocal sections of anti-vacuolin antibody-labeled cells revealed a substantial increase in the number of vesicular structures per nucleus in dymA⁻ cells (A′) compared with wild-type cells (A). In contrast to the uniform size of immunostained late endosomal compartments in wild-type cells, the accumulated structures in dymA⁻ cells display a wider variety in size and shape and frequently appear reticular. (B) Confocal sections showing the colocalization (yellow) of dynamin A (Alexa488, green) and vacuolin (Cy3, red) in Ax2 cells expressing GFP–dynamin A. The large vacuolin-positive compartment shows prominent, punctate dynamin A staining (see also right cell in panel D). (C) Confocal sections showing the localization of GFP–dynamin A (Alexa488, green) and the Golgi apparatus as visualized with antibody 190-340-8 (Cy3, red). (D) Localization of GFP–dynamin A (Alexa488, green) in comparison to the distribution of mitochondria (Cy3, red). Mitochondria were labeled with mAb 70-100-1, directed against a mitochondrial porin from D. discoideum. Bar, 10 μm. Magnification in panel A is identical to A′.