Cloning and mRNA expression of human unconventional myosin-IC. A homologue of amoeboid myosins-I with a single IQ motif and an SH3 domain.
The complete deduced amino acid sequence and mRNA expression of human unconventional myosin-IC (HuncM-IC) are described. Sequencing of overlapping cDNA clones reveals a message of 4666 nucleotides with a single open reading frame predicted to encode a 127 kDa protein of 1109 amino acids. HuncM-IC is composed of three discrete regions: a characteristic N-terminal myosin head with predicted actin and ATP-binding sites; a neck domain with an "IQ motif", predicted to bind a single light chain; and a C-terminal tail with a putative membrane-binding site. In addition, the tail contains an src-homology 3 domain. The presence of a single IQ motif and an src-homology 3 domain is reminiscent of "long-tailed" myosins-I from amoeboid organisms, a supposition confirmed by multiple sequence alignment. Northern blot analysis of human tissues shows that HuncM-IC is ubiquitously expressed, with the highest levels in kidney, prostate, colon, liver and ovary. The results show that "amoeboid" myosins-I are not restricted to amoeboid organisms, rather they are expressed in the metazoa as well.
Bement
W M
WM
Department of Biology, Yale University, New Haven, CT 06520-8103.
Wirth
J A
JA
Mooseker
M S
MS
D000048:Acanthamoeba / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004023:Dictyostelium / Q000737:chemistry; D006801:Humans; D008969:Molecular Sequence Data; D009218:Myosins / Q000737:chemistry* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid
D012333:RNA, Messenger; D009218:Myosins