Intermediate subunit of the Gal/GalNAc lectin of Entamoeba histolytica is a member of a gene family containing multiple CXXC sequence motifs.
Killing by Entamoeba histolytica requires parasite adherence to host galactose- and N-acetyl-D-galactosamine (Gal/GalNAc)-containing cell surface receptors. A 260-kDa heterodimeric E. histolytica Gal/GalNAc lectin composed of heavy (Hgl) and light (Lgl) subunits has been previously described. Here we present the cloning and characterization of Igl, a 150-kDa intermediate subunit of the Gal/GalNAc lectin. Igl, Hgl, and Lgl colocalized on the surface membrane of trophozoites. Two unlinked copies of genes encoding Igl shared 81% amino acid sequence identity (GenBank accession no. AF337950 and AF337951). They encoded cysteine-rich proteins with amino- and carboxy-terminal hydrophobic signal sequences characteristic of glycosylphosphatidylinositol (GPI)-anchored membrane proteins. The igl genes lacked carbohydrate recognition domains but were members of a large family of amebic genes containing CXXC and CXC motifs. These data indicate that Igl is part of the parasite's multimolecular Gal/GalNAc adhesin required for host interaction.
Cheng
X J
XJ
Department of Infectious Diseases, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa 259-1193, Japan.
Hughes
M A
MA
Huston
C D
CD
Loftus
B
B
Gilchrist
C A
CA
Lockhart
L A
LA
Ghosh
S
S
Miller-Sims
V
V
Mann
B J
BJ
Petri
W A
WA
Tachibana
H
H
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D015139:Blotting, Southern; D003545:Cysteine / Q000737:chemistry; D016054:DNA, Protozoan / Q000032:analysis; D004748:Entamoeba histolytica / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D037102:Lectins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
D016054:DNA, Protozoan; C434499:Igl1 protein, Entamoeba histolytica; C434500:Igl2 protein, Entamoeba histolytica; D037102:Lectins; D015800:Protozoan Proteins; D003545:Cysteine