An ancient, highly conserved family of cysteine-rich protein domains revealed by cloning type I and type II murine macrophage scavenger receptors.
Scavenger receptors have been implicated in the development of atherosclerosis and other macrophage-associated functions. The bovine type I and type II scavenger receptors are multidomain transmembrane proteins that differ only by the presence in the type I receptor of an additional, extracellular cysteine-rich C-terminal domain. The isolation of type I and type II receptor cDNAs from a murine macrophage cell line, P388D1, establishes the presence of mRNAs encoding both receptor types in a single cell. Their sequences are highly similar to the bovine cDNAs. Receptor type-specific cDNA probes map to a common locus on murine chromosomes 8, suggesting that a single gene encodes both mRNAs. The type I-specific scavenger receptor cysteine-rich (SRCR) domain helps define a previously unrecognized family of remarkably well-conserved domains. Highly homologous SRCR domains (one, three, or four per polypeptide chain) are found in diverse secreted and cell-surface proteins from humans (e.g., CD5, complement factor I), mice (Ly-1), and sea urchins (speract receptor).
Freeman
M
M
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Ashkenas
J
J
Rees
D J
DJ
Kingsley
D M
DM
Copeland
N G
NG
Jenkins
N A
NA
Krieger
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003545:Cysteine; D004247:DNA / Q000235:genetics; D008264:Macrophages; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D009841:Oligonucleotides; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011971:Receptors, Immunologic / Q000235:genetics*; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051117:Scavenger Receptors, Class A; D051122:Scavenger Receptors, Class B
D008565:Membrane Proteins; C495140:Msr1 protein, mouse; D009841:Oligonucleotides; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051117:Scavenger Receptors, Class A; D051122:Scavenger Receptors, Class B; D004247:DNA; D003545:Cysteine