Residue gamma153Cys is essential for the formation of the complexes Aalphagamma and Bbetagamma, assembly intermediates for the AalphaBbetagamma complex and intact fibrinogen.

Abstract

BACKGROUND:

Fibrinogen Matsumoto IV was found in a hypofibrinogenemia caused by a heterozygous missense mutation, i.e., the substitution of the fibrinogen gamma-chain residue Cys153 by Arg.

METHODS:

To examine the precise basis for the fibrinogen deficiency, mixtures of any two vectors, the fibrinogen Aalpha-, Bbeta-, gamma- (153Cys) or gammam-(153Ala) chain were transfected into Chinese hamster ovary cells (CHO-Aalpha/gamma, -Aalpha/gammam, -Bbeta/gamma, -Bbeta/gammam). Expression and constitution of each of two chains and their complexes in the individual CHO cell lines were identified by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and immunoblot analysis using polypeptide specific antibodies and two-dimensional electrophoresis (2-DE).

RESULTS:

In the CHO-Aalpha/gamma and -Bbeta/gamma, the Aalpha/gamma- or Bbeta/gamma-complex was formed, whereas in the CHO-Aalpha/gammam and -Bbeta/gammam, no Aalpha/gammam- or Bbeta/gammam-complex was observed. These results demonstrate that gamma153Ala cannot assemble with the Aalpha- and Bbeta-chains, leading to impaired fibrinogen assembly and secretion.

CONCLUSION:

gamma153Cys is an essential residue for the fibrinogen assembly which is dependent on Aalpha/gamma- and Bbeta/gamma-complex formation.

• Authors: Fumiko Terasawa, Kiyotaka Fujita, Nobuo Okumura
• Journal: Clinica chimica acta; international journal of clinical chemistry (Clin Chim Acta) Vol. 353 Issue 1-2 Pg. 157-64 (Mar 2005) ISSN: 0009-8981 [Print] Netherlands
• PMID: 15698603 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Fibrinogen
• Cysteine

Topics

• Animals
• Blotting, Western
• CHO Cells
• Cricetinae
• Cysteine (chemistry)
• Electrophoresis, Gel, Two-Dimensional
• Fibrinogen (chemistry, metabolism)