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C M Stover

Publications and source records attributed to C M Stover.

5 recordsLinked to original sources
PubMed1999

The rat and mouse homologues of MASP-2 and MAp19, components of the lectin activation pathway of complement.

Recently, we described two novel constituents of the multimolecular initiation complex of the mannan-binding lectin (MBL) pathway of complement activation, a serine protease of 76 kDa, termed MASP-2, and a MASP-2 related plasma protein of 19 kDa, termed MAp19. Upon activation of the MBL/MASPs/MAp19 complex, MASP-2 cleaves the fourth complement component C4, while the role of MAp19 within the MBL/MASP-1/MASP-2/MAp19 complex remains to be clarified. In humans, the mRNA species encoding MASP-2 (2.6 kb) and MAp19 (1.0 kb) arise by an alternative polyadenylation/splicing mechanism from a single structural MASP-2 gene. Here, we report the complete primary structures of the rat homologue of MASP-2 and of rat and mouse MAp19. We show that both MASP-2 and MAp19 are part of the rat MBL pathway activation complex and demonstrate their exclusively hepatic biosynthesis. Southern blot and PCR analyses of rat genomic DNA indicate that as in humans, rat MASP-2 and MAp19 are encoded by a single structural gene.

Amino Acid Sequence↗
PubMed1999

Two constituents of the initiation complex of the mannan-binding lectin activation pathway of complement are encoded by a single structural gene.

Mannan-binding lectin (MBL) forms a multimolecular complex with at least two MBL-associated serine proteases, MASP-1 and MASP-2. This complex initiates the MBL pathway of complement activation by binding to carbohydrate structures present on bacteria, yeast, and viruses. MASP-1 and MASP-2 are composed of modular structural motifs similar to those of the C1q-associated serine proteases C1r and C1s. Another protein of 19 kDa with the same N-terminal sequence as the 76-kDa MASP-2 protein is consistently detected as part of the MBL/MASP complex. In this study, we present the primary structure of this novel MBL-associated plasma protein of 19 kDa, MAp19, and demonstrate that MAp19 and MASP-2 are encoded by two different mRNA species generated by alternative splicing/polyadenylation from one structural gene.

Alternative Splicing↗
PubMed1998

Neuronal expression of fractalkine in the presence and absence of inflammation.

Fractalkine is the only as yet known member of a novel class of chemokines. Besides its novel Cys-X-X-X-Cys motif, fractalkine exhibits features which have not been described for any other member of the chemokine family, including its unusual size (397 amino acids human, 395 mouse) and the possession of a transmembrane anchor, from which a soluble form may be released by extracellular cleavage. This report demonstrates the abundant mRNA and fractalkine protein expression in neuronal cells. The neuronal expression of fractalkine mRNA is unaffected by experimentally induced inflammation of central nervous tissue.

Animals↗
PubMed1997

A second serine protease associated with mannan-binding lectin that activates complement.

The complement system comprises a complex array of enzymes and non-enzymatic proteins that is essential for the operation of the innate as well as the adaptive immune defence. The complement system can be activated in three ways: by the classical pathway which is initiated by antibody-antigen complexes, by the alternative pathway initiated by certain structures on microbial surfaces, and by an antibody-independent pathway that is initiated by the binding of mannan-binding lectin (MBL; first described as mannan-binding protein) to carbohydrates. MBL is structurally related to the complement C1 subcomponent, C1q, and seems to activate the complement system through an associated serine protease known as MASP (ref. 4) or p100 (ref. 5), which is similar to C1r and C1s of the classical pathway. MBL binds to specific carbohydrate structures found on the surface of a range of microorganisms, including bacteria, yeasts, parasitic protozoa and viruses, and exhibits antibacterial activity through killing mediated by the terminal, lytic complement components or by promoting phagocytosis. The level of MBL in plasma is genetically determined, and deficiency is associated with frequent infections in childhood, and possibly also in adults (for review, see ref. 6). We have now identified a new MBL-associated serine protease (MASP-2) which shows a striking homology with the previously reported MASP (MASP-1) and the two C1q-associated serine proteases C1r and C1s. Thus complement activation through MBL, like the classical pathway, involves two serine proteases and may antedate the development of the specific immune system of vertebrates.

Amino Acid Sequence↗