Low-density lipoprotein receptor-related protein 1B

Low-density lipoprotein receptor-related protein 1B (LRP1B) is a large cell surface receptor belonging to the LRP family that mediates receptor-mediated endocytosis through ligand binding and internalization (UniProt: Q9NZR2). The protein functions as a potential endocytic receptor, similar to other LDL receptor-related proteins involved in cellular uptake and trafficking of extracellular molecules.

LRP1B is expressed as a transmembrane protein with a molecular mass of approximately 515 kDa. While no disease associations are annotated in the UniProt record, the protein has been detected in quantitative proteomic studies of human brain tissue, suggesting a role in central nervous system homeostasis.

In Alzheimer's disease, LRP1B is down-regulated in post-mortem AD brain tissue compared to age-matched controls (Chaparral AD proteomics). The mean log2 fold-change is −0.37, representing a modest but consistent reduction across the examined subcellular fractions in TMT-labeled quantitative proteomics data. This downregulation may reflect altered endocytic processing or amyloid clearance pathways characteristic of AD pathology.