Role of lysine residues in the interaction of blood coagulation factor VIII with its clearance receptor low-density lipoprotein receptor-related protein

摘要

Lysine residues mediate the interaction between Factor VIII and LRP1 since chemical modification of all lysine residues completely abolishes the interaction with LRP cluster II. Combined hydrogen-deuterium experiments and site-directed mutagenesis reveals that multiple regions scattered throughout the FVIII protein contribute to the interaction with LRP1. 'Hot spot' lysines include K1673/1674, K1813/1818, K1827 in the A3 domain and K2065 and K2092 in the C1 domain. All lysine replacement variants show residual interaction with LRP cluster II suggesting: a concerted interaction mechanism involving lysine residues in multiple domains; a residual role for arginine residues. Structural modelling suggests that the FVIII C1 domain contains a canonical double repeat interaction motif. We propose that LRP cluster II interacts with the FVIII light chain via an extended surface comprising multiple lysine residues, starting at the bottom of the C1 domain extending to the top of the A3 domain.