Abstract
The Scavenger Receptor Cysteine-Rich (SRCR) domain is an ancient and highly conserved protein module of ~100-110 amino acids, which defines a superfamily (SRCR-SF) of either soluble or membrane-bound receptors expressed by hematopoietic and nonhematopoietic cells, at either embryonic or adult stages. The existence of two types of SRCR domains allows the division of the SRCR-SF into two groups. Members of group A contain SRCR domains with 6 cysteine residues and are encoded by two exons, whereas those of group B usually contain 8 cysteines and are encoded by a single exon. Group A members usually present as multidomain mosaic proteins containing single SRCR domains associated to other functional domains, such as enzymatic (protease) domains or collagenous regions. On the contrary, group B members generally present as proteins exclusively composed of tandem repeats of SRCR domains, with or without the presence of CUB and ZP domains thought to be involved in oligomerization but never associated to protease domains. Representatives of either group are found in different animal species, from low invertebrates (sponges) to high vertebrates (mammals). Although no unifying function has been defined for SRCR-SF members, accumulated data, together with the high degree of structural and phylogenetic conservation of SRCR domains indicates that they might subserve basic homeostatic functions, including innate immune defense.
Publication types
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Agglutinins / chemistry
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Agglutinins / immunology
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Agglutinins / physiology
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Amino Acid Oxidoreductases / physiology
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Amino Acid Sequence
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Animals
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Antigens, CD / immunology
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Antigens, CD / physiology
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Antigens, Differentiation, Myelomonocytic / immunology
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Antigens, Differentiation, Myelomonocytic / physiology
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Antigens, Differentiation, T-Lymphocyte / immunology
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Antigens, Differentiation, T-Lymphocyte / physiology
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CD36 Antigens / immunology
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CD36 Antigens / physiology
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CD5 Antigens / immunology
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CD5 Antigens / physiology
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Calcium-Binding Proteins
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DNA-Binding Proteins
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Fibronectins / physiology
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Gene Expression Regulation
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Glycoproteins / chemistry
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Glycoproteins / immunology
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Glycoproteins / physiology
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Humans
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Immunity, Innate / immunology*
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Immunity, Innate / physiology
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Ligands
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Membrane Proteins / immunology
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Membrane Proteins / physiology
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Models, Molecular
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Molecular Sequence Data
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Mucins / chemistry
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Mucins / immunology
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Mucins / physiology
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Protein Structure, Tertiary / genetics
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Protozoan Proteins / immunology
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Protozoan Proteins / physiology
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Receptors, Cell Surface / chemistry
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Receptors, Cell Surface / immunology
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Receptors, Cell Surface / physiology
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Receptors, Immunologic / chemistry
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Receptors, Immunologic / genetics
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Receptors, Immunologic / immunology*
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Receptors, Immunologic / physiology
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Receptors, Scavenger
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Scavenger Receptors, Class A
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Sequence Homology
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Structural Homology, Protein
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Tumor Suppressor Proteins
Substances
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Agglutinins
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Antigens, CD
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Antigens, Differentiation, Myelomonocytic
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Antigens, Differentiation, T-Lymphocyte
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CD163 antigen
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CD36 Antigens
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CD5 Antigens
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CD6 antigen
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Calcium-Binding Proteins
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DMBT1 protein, human
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DNA-Binding Proteins
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Dmbt1 protein, mouse
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Fibronectins
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Glycoproteins
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Ligands
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Marco protein, mouse
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Membrane Proteins
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Mucins
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Ppicap protein, mouse
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Protozoan Proteins
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Receptors, Cell Surface
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Receptors, Immunologic
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Receptors, Scavenger
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SLAP protein, Plasmodium falciparum
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Scavenger Receptors, Class A
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T19 protein, Ovis aries
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Tumor Suppressor Proteins
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egg surface sperm receptor
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glycoprotein 340
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multiadhesive protein, Geodia cydonium
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Amino Acid Oxidoreductases
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LOXL1 protein, human