Domain organisation of class VIII myosins. The myosin motor domain, an N-terminal SH3-like domain, 1 to 7 IQ motifs, a coiled-coil region separated by unique parts and a C-terminal motif defined by two consecutive tryptophans (WW-motif) characterize myosins of class VIII. Tracheophyta also have an N-terminal region in common that we suggest naming the MyTH8 domain. Examples for domain organisations are given by the class VIII myosin sequences of Brassica rapa (Brsp). In general, homologs of the A-branch (myosin-8A, -8C, -8E) contain 3 IQ motifs, while homologs of the B-branch (myosin-8B, -8D, -8F, -8H) have 4 IQ motifs. In addition, the domain organisations of myosin sequences from Selaginella moellendorffii (Sem) and Chlamydomonas reinhardtii (Cr) are shown. They illustrate examples for domain architectures with 7 IQ motifs (SemMyo8A) and without the N-terminal MyTH8 domain (CrMyo8). The class VIII consensus domain architecture is depicted by the lowermost scheme entitled “Myo8 consensus”. All domain schemes are drawn to scale. Small numbers at the C-termini denote the number of residues of each sequence.
Mühlhausen and Kollmar BMC Evolutionary Biology 2013 13:202 doi:10.1186/1471-2148-13-202