PCSK9 binds to multiple receptors and can be functionally inhibited by an EGF-A peptide.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low density lipoprotein receptor (LDLR) and induces its internalization and degradation. PCSK9 binding to LDLR is mediated through the LDLR epidermal growth factor-like repeat A (EGF-A) domain. We show for the first time that an EGF-A peptide inhibits PCSK9-mediated degradation of LDLR in HepG2 cells. In addition to LDLR, we show that PCSK9 also binds directly to ApoER2 and mouse VLDLR. Importantly, binding of PCSK9 to either LDLR or mouse VLDLR was effectively inhibited by EGF-A while binding to ApoER2 was less affected. In contrast, LDL receptor-associated protein (RAP), which interacts with LDL receptor repeat type A (LA) domains, inhibited PCSK9 binding to ApoER2 with greater efficacy than either LDLR or mVLDLR. These data demonstrate that while PCSK9 binds several receptors via its EGF-A binding domain, additional contacts with other receptor domains are also involved.
Shan
LiXin
L
Department of Cardiovascular and Metabolic Disease Research, Schering-Plough Research Institute, 2015 Galloping Hill Road, K-15-1/1945, Kenilworth, NJ 07033, USA.
Pang
Ling
L
Zhang
Rumin
R
Murgolo
Nicholas J
NJ
Lan
Hong
H
Hedrick
Joseph A
JA
D000818:Animals; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000378:metabolism*; D006801:Humans; D026502:LDL-Receptor Related Proteins; D051379:Mice; D010455:Peptides / Q000378:metabolism; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D017434:Protein Structure, Tertiary; D011973:Receptors, LDL / Q000378:metabolism*; D018110:Receptors, Lipoprotein / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*
D026502:LDL-Receptor Related Proteins; D010455:Peptides; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; C036053:VLDL receptor; C098773:low density lipoprotein receptor-related protein 8; D004815:Epidermal Growth Factor; C472125:PCSK9 protein, human; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012697:Serine Endopeptidases