Caveolae-dependent Endocytosis Is Required for Class A Macrophage Scavenger Receptor-mediated Apoptosis in Macrophages.
Summary of "Caveolae-dependent Endocytosis Is Required for Class A Macrophage Scavenger Receptor-mediated Apoptosis in Macrophages."
SR-A (class A macrophage scavenger receptor) is a transmembrane receptor that can bind many different ligands, including modified lipoproteins that are relevant to the development of vascular diseases. However, the precise endocytic pathways of SR-A/mediated ligands internalization are not fully characterized. In this study, we show that the SR-A/ligand complex can be endocytosed by both clathrin- and caveolae-dependent pathways. Internalizations of SR-A-lipoprotein (such as acLDL) complexes primarily go through clathrin-dependent endocytosis. In contrast, macrophage apoptosis triggered by SR-A-fucoidan internalization requires caveolae-dependent endocytosis. The caveolae-dependent process activates p38 kinase and JNK signaling, whereas the clathrin-mediated endocytosis elicits ERK signaling. Our results suggest that different SR-A endocytic pathways have distinct functional consequences due to the activation of different signaling cascades in macrophages.
Affiliation
From the Institute of Reproductive Medicine and.
Journal Details
This article was published in the following journal.
Name: The Journal of biological chemistry
ISSN: 1083-351X
Pages: 8231-9
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21205827
- DOI: http://dx.doi.org/10.1074/jbc.M110.145888
Medical and Biotech [MESH] Definitions
Scavenger Receptors, Class B
A family of scavenger receptors that are predominately localized to CAVEOLAE of the PLASMA MEMBRANE and bind HIGH DENSITY LIPOPROTEINS.
Caveolae
Endocytic/exocytic CELL MEMBRANE STRUCTURES rich in glycosphingolipids, cholesterol, and lipid-anchored membrane proteins that function in ENDOCYTOSIS (potocytosis), transcytosis, and SIGNAL TRANSDUCTION. Caveolae assume various shapes from open pits to closed vesicles. Caveolar coats are composed of CAVEOLINS.
Scavenger Receptors, Class D
A class of scavenger receptors that are specific for oxidized LOW-DENSITY LIPOPROTEINS and apoptotic cells. They are expressed almost exclusively in INTRACELLULAR MEMBRANES of MACROPHAGES.
Scavenger Receptors, Class A
A family of scavenger receptors that mediate the influx of LIPIDS into MACROPHAGES and are involved in FOAM CELL formation.
Scavenger Receptors, Class C
A family of scavenger receptors with broad polyanionic ligand binding properties that are expressed in embryonic insect MACROPHAGES.
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