CopA:GFP localizes to putative Golgi equivalents in Aspergillus nidulans.

The Golgi complex is a main component of the eukaryotic secretory system and functions to modify nascent proteins sent from the endoplasmic reticulum. Ultrastructural studies of filamentous fungi have shown Golgi to be individual smooth membrane cisternae that are referred to as Golgi equivalents or dictyosomes. The Aspergillus nidulans copA gene encodes a homolog of mammalian coat protein (alpha-COP), a constituent of the Golgi-localized COPI vesicle coat. Here, the localization of A. nidulansalpha-COP was examined in live cells using the reporter green fluorescent protein (GFP). CopA:GFP localized to putative Golgi equivalents that were concentrated at hyphal tips. The localization was disrupted by the fungal metabolite brefeldin A. To investigate the significance of the microtubule cytoskeleton in the localization of putative Golgi equivalents, the copA:gfp fusion was expressed in a temperature-sensitive dynein mutant. In addition, a wild-type strain expressing copA:gfp was treated with the microtubule-disrupting drug nocodazole. The results suggest that the microtubule cytoskeleton is not the primary mechanism of localizing putative Golgi equivalents in A. nidulans.