title: Oxygen sensing by protozoans: how they catch their breath.
abstract: Cells must know the local levels of available oxygen and either adapt accordingly or relocate to more favorable environments. Prolyl 4-hydroxylases (P4Hs) are emerging as universal cellular oxygen sensors. In animals, these oxygen sensors respond to decreased oxygen availability by up-regulating hypoxia-inducible transcription factors. In protozoa, the P4Hs appear to activate E3-SCF ubiquitin ligase complexes via a glycosylation-dependent mechanism, potentially to turn over their proteomes. Intracellular parasites are impacted by both types of oxygen-sensing pathways. Since parasites are exposed to diverse oxygen tensions during their life cycles, this review identifies emerging oxygen-sensing mechanisms and discusses how these mechanisms probably contribute to the regulation of unicellular eukaryotes.
authors.affiliation: Department of Biochemistry & Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, 975 NE 10th St., BRC 417, Oklahoma City, OK 73104, USA. Electronic address: Christopher-west@ouhsc.edu.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: West
authors.affiliation: Department of Microbiology and Immunology, University at Buffalo School of Medicine, 347 Biomedical Research Building, 3435 Main Street, Buffalo, NY 14214, USA.
authors.forename: Ira J
authors.initials: IJ
authors.lastname: Blader
mesh_terms: D000222:Adaptation, Physiological; D056890:Eukaryota / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D010100:Oxygen / Q000378:metabolism*; D064828:Prolyl Hydroxylases / Q000378:metabolism*; D015800:Protozoan Proteins / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D015800:Protozoan Proteins; D064828:Prolyl Hydroxylases; D010100:Oxygen