low-density lipoprotein receptor gene family low-density lipoprotein receptor gene family the low-density lipoprotein receptor gene family codes for a class of structurally related cell surface receptors that fulfill diverse biological functions in different organs, tissues, and cell types. the role that is most commonly associated with this evolutionarily ancient family is cholesterol homeostasis (maintenance of appropriate concentration of cholesterol). in humans, excess cholesterol in the blood is captured by low-density lipoprotein (ldl) and removed by the liver via endocytosis of the ldl receptor. recent evidence indicates that the members of the ldl receptor gene family are active in the cell signalling pathways between specialized cells in many, if not all, multicellular organisms. low-density lipoprotein receptor domain class astructure of a cysteine-rich repeat from the low-density lipoprotein receptor.identifierssymbolldl_recept_apfampf00057interproipr002172smartsm00192prositeps50068scop21ldl / scope / supfammembranome5available protein structures:pfam structures / ecod pdbrcsb pdb; pdbe; pdbjpdbsumstructure summary low-density lipoprotein receptor domain class bstructure of the ldl receptor extracellular domain at endosomal ph.identifierssymbolldl_recept_bpfampf00058pfam clan6cl0186interproipr000033smartsm00135prositeps51120scop21lrx / scope / supfamavailable protein structures:pfam structures / ecod pdbrcsb pdb; pdbe; pdbjpdbsumstructure summarypdb1ijq​, 1n7d​, 1npe​ there are seven members of the ldlr family in mammals, namely: ldlr vldl receptor (vldlr) apoer2, or lrp8 low density lipoprotein receptor-related protein 4 also known as multiple epidermal growth factor (egf) repeat-containing protein (megf7) ldlr-related protein 1 ldlr-related protein 1b megalin. human proteins containing this domain listed below are human proteins containing low-density lipoprotein receptor domains: class a c6; c7; 8a; 8b; c9; cd320; cfi; corin; dgcr2; hspg2; ldlr; ldlrad2; ldlrad3; lrp1; lrp10; lrp11; lrp12; lrp1b; lrp2; lrp3; lrp4; lrp5; lrp6; lrp8; mamdc4; mfrp; prss7; rxfp1; rxfp2; sorl1; spint1; sspo; st14; tmprss4; tmprss6; tmprss7; tmprss9 (serase-1b); vldlr; class b egf; ldlr; lrp1; lrp10; lrp1b; lrp2; lrp4; lrp5; lrp5l; lrp6; lrp8; nid1; nid2; sorl1; vldlr;