| Modification Notes |
Members of the LDL receptor gene family, including LDLR (low density lipoprotein receptor), LRP’s (low density lipoprotein related proteins), Megalin (also designated GP330), VLDLR (very low density lipoprotein receptor) and ApoER2, are characterized by a cluster of cysteine-rich class A repeats, epidermal growth factor (EGF)-like repeats, YWTD repeats and an O-linked sugar domain (1,2). LRP1, also designated a-2-macroglobulin receptor, is an endocytic receptor that mediates the uptake of at least 15 ligands, including a-2-macroglobulin and apoE (3–6). LRP1, which is expressed in brain, liver and lung, is also implicated in Alzheimer’s disease (AD), as the human LRP1 gene localizes to a potential AD locus on chromosome 12 (5,6). The human LRP6 gene localizes to chromosome 12p11-p13 and encodes a protein with a unique pattern of four epidermal growth factor (EGF) and three LDLR repeats in the extracellular domain (7). LRP6 mediates Wnt/b-catenin signaling, which controls various developmental processes, including patterning of the body axis, central nervous system and limbs, and regulation of organogenesis (8). |