The human EGF-TM7 family member EMR2 is a heterodimeric receptor expressed on myeloid cells.
The EGF-TM7 family is a group of class B seven-span transmembrane (TM7) receptors expressed predominantly by cells of the immune system. Family members CD97, EMR1, EMR2, EMR3, and ETL are characterized by an extended extracellular region with a variable number of N-terminal epidermal growth factor (EGF)-like domains coupled to a TM7 domain by a stalk. The EGF domain region of the recently identified EMR2 differs from that of CD97 in only 6 out of 236 amino acids. Although small, this difference has been shown to alter ligand specificity. To analyze the structure and cellular distribution of EMR2, a specific monoclonal antibody (2A1) was generated. Use of 2A1 has demonstrated EMR2, like CD97, to be expressed as a heterodimeric receptor consisting of an extracellular alpha part and a TM7/cytoplasmic beta part. Analysis of EMR2 expression on primary blood leukocytes, on hematopoietic cells lines, and in situ revealed a myeloid-restricted profile. Highest expression levels were detected on the more mature CD16(+) blood monocytes, on macrophages, and on BDCA-3(+) myeloid DC, whereas little if any expression was found on granulocytes. Unlike CD97, no expression was observed on resting or activated lymphocytes. Different expression patterns and the inability of EMR2 to interact with the CD97 ligand CD55 indicate that the molecular twins EMR2 and CD97 likely have nonredundant functions.
Kwakkenbos
Mark J
MJ
Laboratory for Experimental Immunology, Academic Medical Center, University of Amsterdam, The Netherlands.
Chang
Gin-Wen
GW
Lin
Hsi-Hsien
HH
Pouwels
Walter
W
de Jong
Esther C
EC
van Lier
René A W
RA
Gordon
Siamon
S
Hamann
Jörg
J
D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000737:chemistry / Q000378:metabolism; D019281:Dimerization; D004815:Epidermal Growth Factor / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D006098:Granulocytes / Q000276:immunology / Q000378:metabolism; D006801:Humans; D037102:Lectins / Q000032:analysis; D008214:Lymphocytes / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000032:analysis; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D022423:Myeloid Cells / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D014018:Tissue Distribution
C412456:ADGRE2 protein, human; C095004:ADGRE5 protein, human; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D037102:Lectins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D004815:Epidermal Growth Factor