PMID: 9171889Dec 1, 1996Paper

In vitro expression of the beta subunit of human complement component C8

Molecular Immunology
C S LetsonJames M Sodetz

Abstract

Human C8 is one of five components of the cytolytic C5b-9 complex of complement. It is an oligomeric protein composed of three subunits (alpha, beta, gamma) encoded in separate genes. These are arranged as a disulfide-linked alpha-gamma dimer and a noncovalently associated beta chain. Biosynthesis studies and analyses of humans with hereditary C8 deficiencies suggest that C8 alpha-gamma synthesis and secretion can occur independently of C8 beta, but that serum levels of C8 beta are dependent on C8 alpha-gamma. One aim of the present study was to determine if functional human C8 beta could be synthesized in the absence of C8 alpha-gamma. Human C8 beta expression constructs were prepared and used to produce recombinant C8 beta (rC8 beta) in insect and COS-7 cells. Both cell types secreted rC8 beta that was similar in size to human C8 beta and exhibited similar ability to associate with human C8 alpha-gamma and form functional C8. A mutant form of C8 beta in which N-glycosylation sites were eliminated was also expressed and found to be functionally similar to rC8 beta and human C8 beta. These results indicate that C8 alpha-gamma is not required for intracellular processing and secretion of C8 beta. Furthermore, N-linked carbohydra...Continue Reading

References

Jan 1, 1988·Annual Review of Biochemistry·H J Müller-Eberhard
Dec 1, 1986·Scandinavian Journal of Immunology·J TschoppP Späth
Oct 1, 1982·The Journal of Clinical Investigation·K M MorrisH R Colten

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Citations

Nov 4, 2000·Biochimica Et Biophysica Acta·S F SchreckJ M Sodetz

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