Molecular characterization of myosin IB from the lower eukaryote Entamoeba histolytica, a human parasite.
The complete amino acid sequence of the Entamoeba histolytica unconventional myosin IB (Eh-myosin IB) is reported. Sequencing of overlapping cDNA fragments reveals a single open reading frame which predicts a 130 kDa protein of 1049 aa. Eh-myosin IB presents the three characteristics domains of myosins I subclass 1. This protein presents homology with myosins IB from other amoebae, but striking homologies with vertebrate unconventional myosins were also observed. The predicted actin and ATP-binding sites are located in the head domain. The heavy chain phosphorylation region is homologous to metazoan myosins I with an acidic residue present at the phosphorylation site. In the neck domain, an IQ motif indicates potential binding of calmodulin to the myosin I heavy chain. In the tail of Eh-myosin IB the three characteristic regions of myosin I are found. A putative membrane binding domain a very short domain rich in alanine and proline we demonstrate to be functional for actin binding, and the src-homology 3 domain. The Entamoeba histolytica myosin IB is the first unconventional myosin so far described in a lower eukaryote.
Vargas
M
M
Unité de Pathogénie Microbienne Moléculaire, Institut National de la Santé et de la Recherche Médicale U389 Institut Pasteur, Paris, France.
Voigt
H
H
Sansonetti
P
P
Guillen
N
N
D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping; D017931:DNA Primers; D018076:DNA, Complementary; D004748:Entamoeba histolytica / Q000235:genetics* / Q000502:physiology; D017125:Genes, Protozoan; D006801:Humans; D008969:Molecular Sequence Data; D009218:Myosins / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D000199:Actins; D017931:DNA Primers; D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D000255:Adenosine Triphosphate; D009218:Myosins