title: Histidine phosphorylation of annexin I in airway epithelia.
abstract: Although [Cl(-)](i) regulates many cellular functions including cell secretion, the mechanisms governing these actions are not known. We have previously shown that the apical membrane of airway epithelium contains a 37-kDa phosphoprotein (p37) whose phosphorylation is regulated by chloride concentration. Using metal affinity (chelating Fe(3+)-Sepharose) and anion exchange (POROS HQ 20) chromatography, we have purified p37 from ovine tracheal epithelia to electrophoretic homogeneity. Sequence analysis and immunoprecipitation using monoclonal and specific polyclonal antibodies identified p37 as annexin I, a member of a family of Ca(2+)-dependent phospholipid-binding proteins. Phosphate on [(32)P]annexin I, phosphorylated using both [gamma-(32)P]ATP and [gamma-(32)P]GTP, was labile under acidic but not alkaline conditions. Phosphoamino acid analysis showed the presence of phosphohistidine. The site of phosphorylation was localized to a carboxyl-terminal fragment of annexin I. Our data suggest that cAMP and AMP (but not cGMP) may regulate annexin I histidine phosphorylation. We propose a role for annexin I in an intracellular signaling system involving histidine phosphorylation.
authors.affiliation: Tayside Institute of Child Health, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom. r.muimo@dundee.ac.uk
authors.forename: R
authors.initials: R
authors.lastname: Muimo
authors.forename: Z
authors.initials: Z
authors.lastname: Hornickova
authors.forename: C E
authors.initials: CE
authors.lastname: Riemen
authors.forename: V
authors.initials: V
authors.lastname: Gerke
authors.forename: H
authors.initials: H
authors.lastname: Matthews
authors.forename: A
authors.initials: A
authors.lastname: Mehta
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017305:Annexin A1 / Q000302:isolation & purification / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006639:Histidine / Q000031:analogs & derivatives / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D019606:Phosphoamino Acids / Q000378:metabolism; D010766:Phosphorylation; D012137:Respiratory System / Q000166:cytology / Q000378:metabolism*; D012756:Sheep; D014132:Trachea / Q000166:cytology / Q000378:metabolism
chemical_list: D017305:Annexin A1; D019606:Phosphoamino Acids; D006639:Histidine; D004533:Egtazic Acid; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; C005436:phosphohistidine