Plasma membrane tetraspanin CD81 complexes with proprotein convertase subtilisin/kexin type 9 (PCSK9) and low density lipoprotein receptor (LDLR), and Its levels are reduced by PCSK9

Abstract

Background: PCSK9 is a modulator of LDLR and the tetraspanin CD81. Results: Although CD81 is targeted for degradation by PCSK9 in an LDLR-independent manner, it can associate with the LDLR. Conclusion: CD81 and LDLR are two independent targets of PCSK9 that bind to each other. Significance: Structure-based mutagenesis of PCSK9 reveals functional interactions of CD81 with LDLR and PCSK9.