The NUDF protein of Aspergillus nidulans, which is required for nuclear migration through the fungal mycelium, closely resembles the LIS1 protein required for migration of neurons to the cerebral cortex in humans. Genetic experiments suggested that NUDF influences nuclear migration by affecting cytoplasmic dynein. NUDF interacts with another protein, NUDE, which also affects nuclear migration in A. nidulans. Interactions among LIS1, NUDE, dynein, and ␥-tubulin have been demonstrated in animal cells. In this paper we examine the interactions of the A. nidulans NUDF and NUDE proteins with components of dynein, dynactin, and with ␣-and ␥-tubulin. We show that NUDF binds directly to ␣-and ␥-tubulin and to the first P-loop of the cytoplasmic dynein heavy chain, whereas NUDE binds directly to ␣-and ␥-tubulin, to NUDK (actin-related protein 1), and to the NUDG dynein LC8 light chain. The data suggest a direct role for NUDF in regulation of the dynein heavy chain and an effect on other dynein/dynactin subunits via NUDE. The interactions between NUDE, NUDF, and ␥-tubulin suggest that this protein may also be involved in the regulation of dynein function. Additive interactions between NUDE and dynein and dynactin subunits suggest that NUDE acts as a scaffolding factor between components.

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