Potential cell surface proteins that bind and internalize ligands in the process of receptor-mediated endocytosis. Binds LRPAP1, PLAU, PLAT and SERPINE1; binding is followed by internalization and degradation of the ligands. Expressed in thyroid gland and in salivary gland, as well as in adult and fetal brain. The gene is preferentially inactivated in one histological type of lung cancer (non-small cell lung cancer (NSCLC)). May thus play an important role in tumorigenesis of NSCLCs. Belongs to the LDLR family.