Selective expression of RT6 superfamily in human bronchial epithelial cells.
RT6 proteins are glycosylphosphatidylinositol (GPI)-linked alloantigens that are localized to cytotoxic T lymphocytes and that have nicotinamide adenine dinucleotide glycohydrolase and adenosine diphosphate (ADP)-ribosyltransferase activities. In view of the importance of GPI-linked surface proteins in mediating interactions of cells with their milieu, and the varied functions of airway cells in inflammation, we undertook the present study to determine whether human homologues of the RT6 superfamily of ADP-ribosyltransferases (ART) are expressed in pulmonary epithelial cells. We hypothesized that these surface proteins or related family members may be present in cells that interact with inflammatory cells, and that they may thereby be involved in intercellular signaling. Using in situ analysis and Northern blot analysis, we identified ART1 messenger RNA (mRNA) in airway epithelial cells. As expected for GPI-anchored proteins, the localization of ART1 at the apical surface of ciliated epithelial cells was demonstrated by staining with polyclonal anti-ART1 antibody, and was confirmed by loss of this immunoreactivity after treatment with phosphatidylinositol-specific phospholipase C (PI-PLC), which selectively cleaves GPI anchors and releases proteins from the plasma membrane. Using in situ hybridization with specific ART3 and ART4 oligonucleotides, we also identified two additional members of the RT6 superfamily in epithelial cells. In accord with these findings, we identified ART3 and ART4 mRNAs through reverse transcription- polymerase chain reaction of polyadenine-positive RNA from human trachea. Interestingly, these proteins appeared to be preferentially localized to the airway epithelium. The localized expression of these members of the RT6 superfamily in human pulmonary epithelial cells may reflect a role for them in cell-cell signaling during immune responses within the airway.
Balducci
E
E
Pulmonary-Critical Care Medicine Branch and Pathology Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
Horiba
K
K
Usuki
J
J
Park
M
M
Ferrans
V J
VJ
Moss
J
J
D036002:ADP Ribose Transferases / Q000032:analysis / Q000378:metabolism*; D000945:Antigens, Differentiation, T-Lymphocyte; D001980:Bronchi / Q000033:anatomy & histology / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004847:Epithelial Cells / Q000378:metabolism; D005656:Fungal Proteins / Q000032:analysis / Q000378:metabolism; D058851:GPI-Linked Proteins; D006801:Humans; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008168:Lung / Q000033:anatomy & histology; D008562:Membrane Glycoproteins / Q000032:analysis / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism; D005810:Multigene Family; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D010738:Type C Phospholipases / Q000494:pharmacology
D000945:Antigens, Differentiation, T-Lymphocyte; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D012333:RNA, Messenger; C062214:SWI4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D036002:ADP Ribose Transferases; D011065:Poly(ADP-ribose) Polymerases; C449301:ART1 protein, human; C105233:ART3 protein, human; C105234:ART4 protein, human; C090163:Art2b protein, rat; D010738:Type C Phospholipases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase