Thromb Haemost 1996; 76(03): 292-301
DOI: 10.1055/s-0038-1650574
Original Article
Schattauer GmbH Stuttgart

A Mutant (Arg327→His) GPIIb Associated to Thrombasthenia Exerts a Dominant Negative Effect in Stably Transfected CHO Cells

Milagros Ferrer
The Department of Pathophysiology and Human Molecular Genetics, Centro de Investigaciones Biologicas (CSIC), Madrid, Spain
,
Marta Fernandez-Pinel
The Department of Pathophysiology and Human Molecular Genetics, Centro de Investigaciones Biologicas (CSIC), Madrid, Spain
,
Consuelo Gonzalez-Manchon
The Department of Pathophysiology and Human Molecular Genetics, Centro de Investigaciones Biologicas (CSIC), Madrid, Spain
,
Jose Gonzalez
1   The Unidad de Bioffsica, Instituto de Qufmica Fisica, CSIC, Madrid, Spain
,
Matilde S Ayuso
The Department of Pathophysiology and Human Molecular Genetics, Centro de Investigaciones Biologicas (CSIC), Madrid, Spain
,
Roberto Parrilla
The Department of Pathophysiology and Human Molecular Genetics, Centro de Investigaciones Biologicas (CSIC), Madrid, Spain
› Author Affiliations
Further Information

Publication History

Received: 09 October 1995

Accepted after resubmission22 May 1996

Publication Date:
26 July 2018 (online)

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Summary

This work reports the structural and functional characterization of the platelet glycoprotein complex GPIIb-IIIa (integrin αIIbβ3) in a patient of type II Glanzmann thrombasthenia, bearing a homozygous G→A base transition at position 1074 of GPIIb that results in an Arg327→His substitution.

CHO cells stably transfected with cDNA encoding His327GPIIb showed a drastic reduction in the surface expression of αIIbβ3 complex relative to control cells transfected with wild type GPIIb. Immunopre-cipitation analysis demonstrated that GPIIb synthesis, heterodimeriza-tion, and short term maturation were not impeded, suggesting that conformational changes dependent on Arg327 of GPIIb may play an essential role in either the rate of maturation and/or transport of heterodimers to the cell surface.

Cotransfection of CHO cells with equimolar amounts of cDNAs encoding wild type and mutant His327-GPIIb led to a marked reduction in the surface expression of αIIbβ3. This novel observation of a dominant-negative effect of the mutant His327αIIb subunit provides a molecular basis for the reduced platelet αIIbβ3 content observed in the heterozygous offspring.