RRC ID 54465
Author Inoue N, Fukui A, Nomura M, Matsumoto M, Nishizawa Y, Toyoshima K, Seya T.
Title A novel chicken membrane-associated complement regulatory protein: molecular cloning and functional characterization.
Journal J Immunol
Abstract A cDNA encoding a membrane-associated complement (C) regulatory protein was identified here for the first time in an oviparous vertebrate, chicken. This protein, named Cremp, possessed five short consensus repeats (SCRs) and one SCR-like domain followed by a transmembrane domain and a cytoplasmic tail. SCR1/SCR2 of Cremp were 43.6% identical with SCR2/SCR3 of human decay-accelerating factor (CD55), and SCR3/SCR4 were 45.3% identical with those of human membrane cofactor protein (CD46). Cremp is likely to be an ancestral hybrid protein of human decay-accelerating factor and membrane cofactor protein rather than a homolog of rodent C receptor 1-related protein y, which structurally resembles human CR1 (CD35). Chinese hamster ovary cells transfected with Cremp were efficiently protected from chicken C but not from human or rabbit C in both classical and alternative pathways. Thus, chicken Cremp is a membrane C regulator for cell protection against homologous C. Cremp mRNA was seen as a doublet comprised of a faint band of 2.2 kb and a thick band of 3.0 kb on RNA blotting analysis. An Ab against chicken Cremp recognized a single band of 46.8 kDa on immunoblotting. mRNA and protein of Cremp were ubiquitously expressed in all chicken organs tested. Minute amounts of dimer were present in some tissues. Surface expression of Cremp was confirmed by flow cytometry and immunofluorescence analysis. These results suggested that even in nonmammals a C regulatory membrane protein with ubiquitous tissue distribution should be a prerequisite for protection of host cells from homologous C attack.
Volume 166(1)
Pages 424-31
Published 2001-1-1
DOI 10.4049/jimmunol.166.1.424
PMID 11123320
MeSH Amino Acid Sequence Animals Avian Proteins* Base Sequence Blotting, Northern CHO Cells Cell Membrane / genetics Cell Membrane / immunology Cell Membrane / metabolism Chickens Cloning, Molecular Complement Inactivator Proteins / biosynthesis Complement Inactivator Proteins / chemistry Complement Inactivator Proteins / genetics* Complement Inactivator Proteins / immunology* Complement Pathway, Alternative / genetics Complement Pathway, Alternative / immunology Complement Pathway, Classical / genetics Complement Pathway, Classical / immunology Cricetinae Cytotoxicity Tests, Immunologic DNA, Complementary / isolation & purification Glycosylation Humans Membrane Proteins / biosynthesis Membrane Proteins / chemistry Membrane Proteins / genetics* Membrane Proteins / immunology* Molecular Sequence Data RNA, Messenger / biosynthesis Rabbits Transfection
IF 4.886
Times Cited 25
DNA material pCXN-2/Cremp (RDB02945)
Human and Animal Cells RK13(RCB0183)