The EGF-TM7 family: unusual structures at the leukocyte surface.
The isolation of cDNA clones encoding mouse F4/80, human epidermal growth factor (EGF) module-containing mucin-like hormone receptor 1 (EMR1) and human CD97 has resulted in the description of a novel family of seven-transmembrane spanning cell surface molecules. These members of the EGF-TM7 family are characterized by a variable number of NH2-terminal EGF domains and seven transmembrane-spanning hydrophobic regions, which demonstrate a degree of sequence homology to the corresponding region in members of the G-protein-coupled peptide hormone receptor family. The F4/80 molecule is macrophage-restricted, as determined by immunohistochemical analysis of a wide range mouse tissues, while mRNA transcripts encoding EMR1, the predicted human F4/80 homologue, also appear to be abundantly expressed by cells of the myelomonocytic lineage. CD97, for which a cellular ligand has been identified (CD55), is expressed on a diverse array of leukocytes and is markedly upregulated on activated T and B cells. The regulation of expression of the EGF-TM7 genes, the physiologic function(s) of these novel receptors and the further identification of their ligands is the subject of both intense study and this review.
McKnight
A J
AJ
Sir William Dunn School of Pathology, University of Oxford, United Kingdom. andrew.mcknight@path.ox.ac.uk
Gordon
S
S
D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000737:chemistry / Q000502:physiology*; D002135:Calcium-Binding Proteins; D002462:Cell Membrane / Q000737:chemistry / Q000276:immunology*; D002888:Chromosomes, Human, Pair 19; D006801:Humans; D007962:Leukocytes / Q000737:chemistry / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000502:physiology*; D009077:Mucins / Q000737:chemistry / Q000502:physiology*; D011487:Protein Conformation; D043562:Receptors, G-Protein-Coupled
C094471:ADGRE1 protein, human; C095004:ADGRE5 protein, human; C490633:Adgre5 protein, mouse; D015703:Antigens, CD; D000943:Antigens, Differentiation; D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D009077:Mucins; D043562:Receptors, G-Protein-Coupled; C036763:monocyte-macrophage differentiation antigen