Organelle transport and molecular motors in fungi

Polarized growth, secretion of exoenzymes, organelle inheritance, and organelle positioning require vectorial transport along cytoskeletal elements. The discovery of molecular motors and intensive studies on their biological function during the past 3 years confirmed a central role of these mechanoenzymes in morphogenesis and development of yeasts and filamentous fungi. Saccharomyces cerevisiae proved to be an excellent model system, in which the complete set of molecular motors is presumed to be known. Genetic studies combined with cell biological methods revealed unexpected functional relationships between these motors and has greatly improved our understanding of nuclear migration, exocytosis, and endocytosis in yeasts. Tip growth of elongated hyphae, compared to budding, however, does require vectorial transport over long distances. The identification of ubiquitous motors that are not present in yeast indicates that studies on filamentous fungi might be helpful to elucidate the role of motors in long-distance organelle transport within higher eukaryotic cells. (C) 1998 Academic Press.