| First Author | Mentrup T | Year | 2019 |
| Journal | J Exp Med | Volume | 216 |
| Issue | 4 | Pages | 807-830 |
| PubMed ID | 30819724 | Mgi Jnum | J:275231 |
| Mgi Id | MGI:6305962 | Doi | 10.1084/jem.20171438 |
| Citation | Mentrup T, et al. (2019) Atherogenic LOX-1 signaling is controlled by SPPL2-mediated intramembrane proteolysis. J Exp Med 216(4):807-830 |
| abstractText | The lectin-like oxidized LDL receptor 1 (LOX-1) is a key player in the development of atherosclerosis. LOX-1 promotes endothelial activation and dysfunction by mediating uptake of oxidized LDL and inducing pro-atherogenic signaling. However, little is known about modulators of LOX-1-mediated responses. Here, we show that the function of LOX-1 is controlled proteolytically. Ectodomain shedding by the metalloprotease ADAM10 and lysosomal degradation generate membrane-bound N-terminal fragments (NTFs), which we identified as novel substrates of the intramembrane proteases signal peptide peptidase-like 2a and b (SPPL2a/b). SPPL2a/b control cellular LOX-1 NTF levels which, following self-association via their transmembrane domain, can activate MAP kinases in a ligand-independent manner. This leads to an up-regulation of several pro-atherogenic and pro-fibrotic targets including ICAM-1 and the connective tissue growth factor CTGF. Consequently, SPPL2a/b-deficient mice, which accumulate LOX-1 NTFs, develop larger and more advanced atherosclerotic plaques than controls. This identifies intramembrane proteolysis by SPPL2a/b as a novel atheroprotective mechanism via negative regulation of LOX-1 signaling. |
