Expression of two novel recombinant proteins from aortic adventitia (kappafibs) sharing amino acid sequences with cytomegalovirus.
We have recently purified and partially sequenced a microfibrillar protein from human aortic adventitia (aneurysm-associated antigenic protein, 40 kDa [AAAP-40]) that is immunoreactive with immunoglobulin (IgG) from the wall of abdominal aortic aneurysms (AAAs). It shares motifs with Ig kappa (which may act as a binding site for interaction with integrins), cytomegalovirus (which may be a molecular mimic in the pathogenesis of AAA), and vitronectin and the fibrinogens. A cDNA library was constructed from the aortic adventitia of a AAA. The library was screened with either rabbit anti-vitronectin antibody or rabbit anti-fibrinogen antibody. Positive plaques were purified and expressed in a strain of Escherichia coli. The clone sequences were analyzed. The expressed proteins were separated by SDS/PAGE and the immunoblots were probed with either AAA IgG or anti-human Ig kappa antibody. Experimental cell lines, transfected with the clones (clones 1 and 5), synthesized recombinant proteins (rAAAP-CL1 and rAAAP-CL5), detectable in Western immunoblots with AAA IgG. A prediction of the tertiary structure resembles well-characterized cell adhesion molecules. These findings suggest that there is a novel family of matrix proteins that may use immunoglobulin motifs as binding sites for cellular integrins and that there are matrix proteins in addition to AAAP-40 that may serve as autoantigens in the pathogenesis of AAA disease.
Ozsvath
K J
KJ
Columbia University, New York, New York, USA.
Hirose
H
H
Xia
S
S
Chew
D
D
Knoetgen
J
J
Tilson
M D
MD
D000595:Amino Acid Sequence; D001011:Aorta / Q000737:chemistry*; D001014:Aortic Aneurysm / Q000378:metabolism*; D001324:Autoantigens / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000235:genetics*; D003285:Contractile Proteins / Q000235:genetics*; D003587:Cytomegalovirus / Q000737:chemistry; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000737:chemistry; D007136:Immunoglobulins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D000072260:RNA Splicing Factors; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry
D001324:Autoantigens; D015815:Cell Adhesion Molecules; D003285:Contractile Proteins; D016326:Extracellular Matrix Proteins; D007145:Immunoglobulin kappa-Chains; D007136:Immunoglobulins; D000072260:RNA Splicing Factors; D014764:Viral Proteins; C016598:microfibrillar protein