The LW blood group glycoprotein is homologous to intercellular adhesion molecules.
The LW blood group antigens reside on a 42-kDa erythrocyte membrane glycoprotein that was purified by immunoaffinity and partially sequenced. From this information, a specific PCR-amplified DNA fragment was used to screen a lambda gt11 human bone marrow cDNA library. Two forms of cDNA were isolated; the first encoded a single spanning transmembrane protein of 270 amino acids, including a 29-amino acid peptide signal and four potential N-glycosylation sites, and the second encoded a shortened protein form of 236 residues devoid of transmembrane and cytoplasm domains. A rabbit antibody raised against the 15 N-terminal amino acids of the predicted protein reacted on immunoblots with authentic LW glycoprotein and in indirect agglutination test with all human erythrocytes except those from LW(a-b-). This showed that the protein encoded by these clones was LW gene product and suggested that the N terminus of the LW protein is oriented extracellularly. Most interestingly, the LW protein was found to exhibit sequence similarities (with approximately 30% identity) with intercellular adhesion molecules ICAM-1, -2, and -3, which are the counter-receptors for the lymphocyte function-associated antigens LFA-1. The extracellular domain of LW consists, like that of ICAM-2, of two immunoglobulin-like domains, and the critical residues involved in the binding of LFA-1 to ICAMs were partially conserved in LW.
Bailly
P
P
Institut National de la Santé et de la Recherche Médicale Unité U76, Institut National de Transfusion Sanguine, Paris, France.
Hermand
P
P
Callebaut
I
I
Sonneborn
H H
HH
Khamlichi
S
S
Mornon
J P
JP
Cartron
J P
JP
D000595:Amino Acid Sequence; D001483:Base Sequence; D001789:Blood Group Antigens / Q000737:chemistry*; D015815:Cell Adhesion Molecules / Q000737:chemistry*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D012204:Rh-Hr Blood-Group System / Q000737:chemistry / Q000235:genetics*
D001789:Blood Group Antigens; D015815:Cell Adhesion Molecules; D017931:DNA Primers; D018076:DNA, Complementary; D006023:Glycoproteins; D012204:Rh-Hr Blood-Group System