title: Insect transferrins: multifunctional proteins.
abstract: BACKGROUND
  Many studies have been done evaluating transferrin in insects. Genomic analyses indicate that insects could have more than one transferrin. However, the most commonly studied insect transferrin, Tsf1, shows greatest homology to mammalian blood transferrin.
  
  
  METHODS
  Aspects of insect transferrin structure compared to mammalian transferrin and the roles transferrin serves in insects are discussed in this review.
  
  
  CONCLUSIONS
  Insect transferrin can have one or two lobes, and can bind iron in one or both. The iron binding ligands identified for the lobes of mammalian blood transferrin are generally conserved in the lobes of insect transferrins that have an iron binding site. Available information supports that the form of dietary iron consumed influences the regulation of insect transferrin. Although message is expressed in several tissues in many insects, fat body is the likely source of hemolymph transferrin. Insect transferrin is a vitellogenic protein that is down-regulated by Juvenile Hormone. It serves a role in transporting iron to eggs in some insects, and transferrin found in eggs appears to be endowed from the female. In addition to the roles of transferrin in iron delivery, this protein also functions to reduce oxidative stress and to enhance survival of infection.
  
  
  CONCLUSIONS
  Future studies in Tsf1 as well as the other insect transferrins that bind iron are warranted because of the roles of transferrin in preventing oxidative stress, enhancing survival to infections and delivering iron to eggs for development. This article is part of a Special Issue entitled Transferrins: Molecular mechanisms of iron transport and disorders.
authors.affiliation: Department of Nutritional Sciences, College of Agriculture and Life Sciences, The University of Arizona, Tucson, Arizona 85721, USA. dlgeiser@email.arizona.edu
authors.forename: Dawn L
authors.initials: DL
authors.lastname: Geiser
authors.forename: Joy J
authors.initials: JJ
authors.lastname: Winzerling
mesh_terms: D000818:Animals; D001665:Binding Sites; D007313:Insecta / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D007605:Juvenile Hormones / Q000378:metabolism; D018384:Oxidative Stress; D011485:Protein Binding; D014168:Transferrin / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D007605:Juvenile Hormones; D014168:Transferrin; D007501:Iron