Figure 3. Schematic representations of the subcellular organization of key components of the A. nidulans secretory pathway. The four cartoons display the distribution of different cytoskeletal structures and compartments involved in secretion. The plus-ends of MTs (dark green) arising from the spindle pole bodies reach the tip. The Spitzenkörper located under the apical plasma membrane contains vesicles awaiting fusion with the plasma membrane and appears to be the place from which actin cables (red) radiate. The position of the subapical endocytic ring where actin patches predominate is indicated in brown. Late Golgi elements are strongly polarized and excluded from the tip region. Early Golgi elements (as labeled with Sed5 t-SNARE) and ERESs (as labeled with Sec23) are less polarized and invade the tip region. ERESs are very abundant and more numerous than early Golgi elements.