This family is a novel family of eukaryotic protein kinase catalytic domains, which have no detectable similarity to conventional kinases. The family contains myosin heavy chain kinases [1,2] and Elongation Factor-2 kinase and a bifunctional ion channel [3]. This family is known as the alpha-kinase family [4]. The structure of the kinase domain [5] revealed unexpected similarity to eukaryotic protein kinases in the catalytic core as well as to metabolic enzymes with ATP-grasp domains.

1: Structural analysis of myosin heavy chain kinase A from Dictyostelium. Evidence for a highly divergent protein kinase domain, an amino-terminal coiled-coil domain, and a domain homologous to the beta-subunit of heterotrimeric G proteins. Futey LM, Medley QG, Cote GP, Egelhoff TT; J Biol Chem 1995;270:523-529. PMID:7822274

2: Mapping of the novel protein kinase catalytic domain of Dictyostelium myosin II heavy chain kinase A. Cote GP, Luo X, Murphy MB, Egelhoff TT; J Biol Chem 1997;272:6846-6849. PMID:9054368

3: TRP-PLIK, a bifunctional protein with kinase and ion channel activities. Runnels LW, Yue L, Clapham DE; Science 2001;291:1043-1047. PMID:11161216

4: Alpha-kinases: a new class of protein kinases with a novel catalytic domain. Ryazanov AG, Pavur KS, Dorovkov MV; Curr Biol 1999;9:43-45. PMID:10021370

5: Crystal structure of the atypical protein kinase domain of a TRP channel with phosphotransferase activity. Yamaguchi H, Matsushita M, Nairn AC, Kuriyan J; Mol Cell 2001;7:1047-1057. PMID:11389851