The misato protein contains three distinct, conserved domains, segments I, II and III. Segments I and III are common to Tubulins Pfam:PF00091, but segment II aligns with myosin heavy chain sequences from D. melanogaster (PIR C35815), rabbit (SP P04460), and human (PIR S12458). Segment II of misato is a major contributor to its greater length compared with the various tubulins. The most significant sequence similarities to this 54-amino acid region are from a motif found in the heavy chains of myosins from different organisms. A comparison of segment II with the vertebrate myosin heavy chains reveals that it is homologous to a myosin peptide in the hinge region linking the S2 and LMM domains. Segment II also contains heptad repeats which are characteristic of the myosin tail alpha-helical coiled-coils [1]. This myosin-like homology may be due only to the fact that both myosin and Misato carry coiled-coils, which appear similar but are not necessarily homologous (Wood V, personal communication).

1: An essential cell division gene of Drosophila, absent from Saccharomyces, encodes an unusual protein with tubulin-like and myosin-like peptide motifs. Miklos GL, Yamamoto M, Burns RG, Maleszka R; Proc Natl Acad Sci U S A. 1997;94:5189-5194. PMID:9144213