title: Heme scavenging and the other facets of hemopexin.
abstract: Hemopexin is an acute-phase plasma glycoprotein, produced mainly by the liver and released into plasma, where it binds heme with high affinity. Other sites of hemopexin synthesis are the nervous system, skeletal muscle, retina, and kidney. The only known receptor for the heme-hemopexin complex is the scavenger receptor, LDL receptor-related protein (LRP)1, which is expressed in most cell types, thus indicating multiple sites of heme-hemopexin complex recovery. The better-characterized function of hemopexin is heme scavenging at the systemic level, consisting of the transport of heme to the liver, where it is catabolyzed or used for the synthesis of hemoproteins or exported to bile canaliculi. This is important both in physiologic heme management for heme-iron recycling and in pathologic conditions associated with intravascular hemolysis to prevent the prooxidant and proinflammatory effects of heme. Other than scavenging heme, the heme-hemopexin complex has been shown to be able to activate signaling pathways, thus promoting cell survival, and to modulate gene expression. In this review, the importance of heme scavenging by hemopexin, as well as the other emerging functions of this protein, are discussed.
authors: Molecular Biotechnology Center, University of Torino, Torino, Italy. emanuela.tolosano@unito.it
authors: Emanuela
authors: E
authors: Tolosano
authors: Sharmila
authors: S
authors: Fagoonee
authors: Noemi
authors: N
authors: Morello
authors: Francesca
authors: F
authors: Vinchi
authors: Veronica
authors: V
authors: Fiorito
mesh_terms: D000818:Animals; D006418:Heme / Q000378:metabolism*; D006466:Hemopexin / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008099:Liver / Q000378:metabolism; D026503:Low Density Lipoprotein Receptor-Related Protein-1 / Q000378:metabolism; D008954:Models, Biological; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
chemical_list: D026503:Low Density Lipoprotein Receptor-Related Protein-1; D006418:Heme; D006466:Hemopexin