The 95RGD97 sequence on the Aα chain of fibrinogen is essential for binding to its erythrocyte receptor.
Background
Erythrocyte aggregation, a cardiovascular risk factor, is increased by high plasma fibrinogen levels. Here, the effect of different fibrinogen mutations on binding to its human erythrocyte receptor was assessed in order to identify the interaction sites.


Methods
Three fibrinogen variants were tested, specifically mutated in their putative integrin recognition sites on the Aα chain (mutants D97E, D574E and D97E/D574E) and compared with wild-type fibrinogen.


Results
Atomic force microscopy-based force spectroscopy measurements showed a significant decrease both on the fibrinogen-erythrocyte binding force and on its frequency for fibrinogen with the D97E mutation, indicating that the corresponding arginine-glycine-aspartate sequence (residues 95-97) is involved in this interaction, and supporting that the fibrinogen receptor on erythrocytes has a β3 subunit. Changes in the fibrin clot network structure obtained with the D97E mutant were observed by scanning electron microscopy.


Conclusion
These findings may lead to innovative perspectives on the development of new therapeutic approaches to overcome the risks of fibrinogen-driven erythrocyte hyperaggregation.
['Carvalho|Filomena A|FA|', 'Guedes|Ana Filipa|AF|', 'Duval|Cedric|C|', 'Macrae|Fraser L|FL|', 'Swithenbank|Luke|L|', 'Farrell|David H|DH|', 'Ariëns|Robert As|RA|', 'Santos|Nuno C|NC|']
D001665:Binding Sites D004912:Erythrocytes D005337:Fibrin D005340:Fibrinogen D006801:Humans D016023:Integrins D018625:Microscopy, Atomic Force D009154:Mutation D011485:Protein Binding D039341:Receptors, Fibrinogen D013927:Thrombosis
fibrinogen erythrocyte aggregation fibrin clot atomic force microscopy mutant protein