Rida Padmashree C G, Nishikawa Akiko, Won Gena Y, Dean Neta
Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA.
Mol Biol Cell. 2006 Oct;17(10):4364-78. doi: 10.1091/mbc.e06-02-0143. Epub 2006 Jul 19.
Rapid and long-distance secretion of membrane components is critical for hyphal formation in filamentous fungi, but the mechanisms responsible for polarized trafficking are not well understood. Here, we demonstrate that in Candida albicans, the majority of the Golgi complex is redistributed to the distal region during hyphal formation. Randomly distributed Golgi puncta in yeast cells cluster toward the growing tip during hyphal formation, remain associated with the distal portion of the filament during its extension, and are almost absent from the cell body. This restricted Golgi localization pattern is distinct from other organelles, including the endoplasmic reticulum, vacuole and mitochondria, which remain distributed throughout the cell body and hypha. Hyphal-induced positioning of the Golgi and the maintenance of its structural integrity requires actin cytoskeleton, but not microtubules. Absence of the formin Bni1 causes a hyphal-specific dispersal of the Golgi into a haze of finely dispersed vesicles with a sedimentation density no different from that of normal Golgi. These results demonstrate the existence of a hyphal-specific, Bni1-dependent cue for Golgi integrity and positioning at the distal portion of the hyphal tip, and suggest that filamentous fungi have evolved a novel strategy for polarized secretion, involving a redistribution of the Golgi to the growing tip.
膜成分的快速和远距离分泌对于丝状真菌的菌丝形成至关重要，但负责极化运输的机制尚未完全了解。在这里，我们证明在白色念珠菌中，大多数高尔基体复合物在菌丝形成过程中重新分布到远端区域。酵母细胞中随机分布的高尔基体点状结构在菌丝形成过程中向生长尖端聚集，在菌丝延伸过程中与菌丝的远端部分保持关联，而在细胞体中几乎不存在。这种受限的高尔基体定位模式与其他细胞器不同，包括内质网、液泡和线粒体，它们仍分布在整个细胞体和菌丝中。高尔基体的菌丝诱导定位及其结构完整性的维持需要肌动蛋白细胞骨架，但不需要微管。formin Bni1的缺失会导致高尔基体在菌丝特异性地分散成细小分散的囊泡的薄雾，其沉降密度与正常高尔基体无异。这些结果证明了存在一种菌丝特异性的、依赖Bni1的线索来维持高尔基体在菌丝尖端远端的完整性和定位，并表明丝状真菌已经进化出一种新的极化分泌策略，涉及高尔基体重新分布到生长尖端。
