RIO Kinase 3 (RIOK3)

The sudD gene was identified as 1 of 4 genes that are cold-sensitive suppressors of the bimD6 mutation.The deduced 519-amino acid human SUDD protein is 36% identical to A. nidulans sudD.

The A. nidulans, human, and S. cerevisiae SUDD proteins all have an unusual amino acid composition, containing approximately 18% glutamic and aspartic acid residues, and approximately 11% serine and threonine residues. On Western blots, human SUDD migrated as a 60-kD protein. Northern blot analysis indicated that the approximately 4-kb SUDD mRNA is expressed widely in human tissues, with additional smaller transcripts present in testis.