title: Two tetratricopeptide repeat proteins facilitate human aryl hydrocarbon receptor signalling in yeast.
abstract: A human aryl hydrocarbon (Ah) receptor signalling pathway was constructed in yeast and used to identify regulatory proteins that may be related to those present in mammalian cells. The sequence similarity of human hepatitis B protein X-associated protein 2 (XAP2) protein to yeast Cpr7 and Cns1 proteins suggested that these proteins might be involved in Ah receptor signalling in this model system. Ah receptor signalling from a lacZ reporter gene was reduced by approximately 60% in cells that lacked Cpr7. In vitro interaction experiments indicated that a Cpr7-GST fusion protein and Ah receptor formed a complex. Expression of Cpr7, Cns1 and the isolated tetratricopeptide repeat (TPR) region of Cpr7 from plasmids restored Ah receptor signalling function in the Cpr7-deficient strain. Thus, Cpr7 and Cns1 proteins facilitate the signalling of human Ah receptor expressed in yeast, perhaps in the same manner as the TPR-containing XAP2 protein and related chaperone proteins in mammalian cells.
authors.affiliation: Environmental Health Sciences Department, Center for Bioenvironmental Research, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA 70112, USA. rellim@tulane.edu
authors.forename: Charles A
authors.initials: CA
authors.lastname: Miller
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones / Q000737:chemistry / Q000502:physiology*; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000502:physiology*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D020449:Repetitive Sequences, Amino Acid; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D000097322:Peptidyl-Prolyl Isomerase D
chemical_list: D002352:Carrier Proteins; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; D019696:Peptidylprolyl Isomerase; D011506:Proteins; D018336:Receptors, Aryl Hydrocarbon; D029701:Saccharomyces cerevisiae Proteins; C116075:CNS1 protein, S cerevisiae; C000631445:CPR7 protein, S cerevisiae; D000097322:Peptidyl-Prolyl Isomerase D; C103265:aryl hydrocarbon receptor-interacting protein