Midasin (MDN1)

Midasin is present as a single-copy gene encoding a well-conserved protein of approximately 600 kDa in all eukaryotes for which data are available. In humans, the gene maps to 6q15 and encodes a predicted protein of 5596 residues. Sequence alignments of midasin from humans, yeast, Giardia and Encephalitozoon indicate that its domain structure comprises an N-terminal domain, followed by an AAA domain containing six tandem AAA protomers, a linker domain, an acidic domain containing 35-40% aspartate and glutamate, and a carboxy-terminal M-domain that possesses MIDAS sequence motifs and is homologous to the I-domain of integrins. Expression of hemagglutamin-tagged midasin in yeast demonstrates a polypeptide of the anticipated size that is localized principally in the nucleus.