Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLR
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that promotes degradation of cell surface LDL receptors (LDLRs) in selected cell types. Here we used genetic and pharmacological inhibitors to define the pathways involved in PCSK9-mediated LDLR degradation. Inactivating mut...
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| Format: | Article |
| Language: | English |
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Elsevier
2012-09-01
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| Series: | Journal of Lipid Research |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520418358 |
| _version_ | 1818740568977571840 |
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| author | Yan Wang Yongcheng Huang Helen H. Hobbs Jonathan C. Cohen |
| author_facet | Yan Wang Yongcheng Huang Helen H. Hobbs Jonathan C. Cohen |
| author_sort | Yan Wang |
| collection | DOAJ |
| description | Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that promotes degradation of cell surface LDL receptors (LDLRs) in selected cell types. Here we used genetic and pharmacological inhibitors to define the pathways involved in PCSK9-mediated LDLR degradation. Inactivating mutations in autosomal recessive hypercholesterolemia (ARH), an endocytic adaptor, blocked PCSK9-mediated LDLR degradation in lymphocytes but not in fibroblasts. Thus, ARH is not specifically required for PCSK9-mediated LDLR degradation. Knockdown of clathrin heavy chain with siRNAs prevented LDLR degradation. In contrast, prevention of ubiquitination of the LDLR cytoplasmic tail, inhibition of proteasomal activity, or disruption of proteins required for lysosomal targeting via macroautophagy (autophagy related 5 and 7) or the endosomal sorting complex required for trafficking (ESCRT) pathway (hepatocyte growth factor-regulated Tyr-kinase substrate and tumor suppressor gene 101) failed to block PCSK9-mediated LDLR degradation. These findings are consistent with a model in which the LDLR-PCSK9 complex is internalized via clathrin-mediated endocytosis and then routed to lysosomes via a mechanism that does not require ubiquitination and is distinct from the autophagy and proteosomal degradation pathways. Finally, the PCSK9-LDLR complex appears not to be transported by the canonical ESCRT pathway. |
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| format | Article |
| id | doaj.art-357d71efcb0b4374b4e5b9d4a6e1ae83 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-18T01:42:48Z |
| publishDate | 2012-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-357d71efcb0b4374b4e5b9d4a6e1ae832022-12-21T21:25:16ZengElsevierJournal of Lipid Research0022-22752012-09-0153919321943Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLRYan Wang0Yongcheng Huang1Helen H. Hobbs2Jonathan C. Cohen3Department of Molecular Genetics, Howard Hughes Medical Research Institute; Department of Internal MedicineDepartment of Molecular Genetics, Howard Hughes Medical Research Institute; Department of Internal MedicineTo whom correspondence should be addressed. e-mail: helen.hobbs@utsouthwestern.edu (H.H.H.) or jonathan.cohen@utsouthwestern.edu (J.C.C.).; Department of Molecular Genetics, Howard Hughes Medical Research Institute; To whom correspondence should be addressed. e-mail: helen.hobbs@utsouthwestern.edu (H.H.H.) or jonathan.cohen@utsouthwestern.edu (J.C.C.).To whom correspondence should be addressed. e-mail: helen.hobbs@utsouthwestern.edu (H.H.H.) or jonathan.cohen@utsouthwestern.edu (J.C.C.).; University of Texas Southwestern Medical Center, Dallas, TX 75390; To whom correspondence should be addressed. e-mail: helen.hobbs@utsouthwestern.edu (H.H.H.) or jonathan.cohen@utsouthwestern.edu (J.C.C.).Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that promotes degradation of cell surface LDL receptors (LDLRs) in selected cell types. Here we used genetic and pharmacological inhibitors to define the pathways involved in PCSK9-mediated LDLR degradation. Inactivating mutations in autosomal recessive hypercholesterolemia (ARH), an endocytic adaptor, blocked PCSK9-mediated LDLR degradation in lymphocytes but not in fibroblasts. Thus, ARH is not specifically required for PCSK9-mediated LDLR degradation. Knockdown of clathrin heavy chain with siRNAs prevented LDLR degradation. In contrast, prevention of ubiquitination of the LDLR cytoplasmic tail, inhibition of proteasomal activity, or disruption of proteins required for lysosomal targeting via macroautophagy (autophagy related 5 and 7) or the endosomal sorting complex required for trafficking (ESCRT) pathway (hepatocyte growth factor-regulated Tyr-kinase substrate and tumor suppressor gene 101) failed to block PCSK9-mediated LDLR degradation. These findings are consistent with a model in which the LDLR-PCSK9 complex is internalized via clathrin-mediated endocytosis and then routed to lysosomes via a mechanism that does not require ubiquitination and is distinct from the autophagy and proteosomal degradation pathways. Finally, the PCSK9-LDLR complex appears not to be transported by the canonical ESCRT pathway.http://www.sciencedirect.com/science/article/pii/S0022227520418358cholesterollysosomesautophagyendosomeslow density lipoprotein receptor |
| spellingShingle | Yan Wang Yongcheng Huang Helen H. Hobbs Jonathan C. Cohen Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLR Journal of Lipid Research cholesterol lysosomes autophagy endosomes low density lipoprotein receptor |
| title | Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLR |
| title_full | Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLR |
| title_fullStr | Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLR |
| title_full_unstemmed | Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLR |
| title_short | Molecular characterization of proprotein convertase subtilisin/kexin type 9-mediated degradation of the LDLR |
| title_sort | molecular characterization of proprotein convertase subtilisin kexin type 9 mediated degradation of the ldlr |
| topic | cholesterol lysosomes autophagy endosomes low density lipoprotein receptor |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520418358 |
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