Low-density lipoprotein receptor (LDLR) family (LDLR family)

The Low-density lipoprotein receptor (LDLR) family is a group of structurally related cell-surface proteins that mediate the endocytosis of cholesterol-rich lipoproteins (UniProt: P01130). The family includes the namesake Low-density lipoprotein receptor, as well as LDL receptor-related protein 1 (LRP1), the very low-density lipoprotein receptor (VLDLR), and megalin (LRP2), all of which share the ability to bind ligands containing Apolipoprotein E (ApoE) (Go & Mani, 2012). These receptors are fundamental to maintaining cholesterol homeostasis; the Low-density lipoprotein receptor specifically clears the majority of circulating LDL-cholesterol, and its deficiency leads to familial hypercholesterolemia and premature atherosclerosis (PubMed: 22435355). In the central nervous system, family members like ApoER2 and VLDLR are involved in Reelin signaling, which is crucial for brain development and synaptic plasticity (Wikipedia: LDL receptor). Pharmacological intervention typically aims to increase receptor expression on hepatocytes to reduce cardiovascular risk. This is clinically achieved using statins, which increase receptor synthesis, and PCSK9 inhibitors (e.g., evolocumab), which prevent the degradation of the receptor, thereby extending its functional lifespan on the cell membrane (StatPearls: PCSK9 Inhibitors). Consequently, this receptor family is a cornerstone of cardiovascular disease prevention and a target of interest for neurodegenerative disorders.

Other names

LDL receptor familyApoE receptorsLow-density lipoprotein receptor-related proteinsLDLR-related receptors

The primary mechanism involves increasing the density of receptors on the cell surface to enhance the clearance of LDL particles from the plasma. This is achieved either by inhibiting HMG-CoA reductase to trigger compensatory receptor upregulation or by blocking PCSK9-mediated lysosomal degradation of the receptor.