Atypical Protein Kinases (aPKs)

Atypical protein kinases lack sequence similarity to the ePK domain HMM profile, but have been shown experimentally to have protein kinase activity, or are clear homologs of aPKs with demonstrated protein kinase activity. All aPK families are small, several having just one member in vertebrates, and none in invertebrates. Other aPK families may remain to be discovered by biochemical methods, but since most atypical families are small, and most biochemically-discovered kinases are ePKs, it is unlikely that many new atypical kinases will be discovered.. Conversely, some of these aPKs may be false positives, if the reports of kinase activity are not correct.