title: Occludin phosphorylation: identification of an occludin kinase in brain and cell extracts as CK2.
abstract: In epithelial and endothelial cells, tight junctions limit paracellular flux of ions, proteins and other macromolecules. However, mechanisms regulating tight junction function are not clear. Occludin, a tight junction protein, undergoes phosphorylation changes in several situations but little is known about occludin kinases. A recombinant C-terminal fragment of occludin is a substrate for a kinase in crude extracts of brain. This activity was purified about 10000-fold and identified as CK2 (casein kinase 2) by peptide mass fingerprinting, immunoblotting and mutation of CK2 sites within the occludin sequence. CK2 is therefore a candidate kinase for regulation of occludin phosphorylation in vivo.
authors.affiliation: Eisai London Research Laboratories Ltd., Bernard Katz Building, University College London, Gower Street, London, WC1E 6BT, UK.
authors.forename: Caroline
authors.initials: C
authors.lastname: Smales
authors.forename: Moira
authors.initials: M
authors.lastname: Ellis
authors.forename: Rachel
authors.initials: R
authors.lastname: Baumber
authors.forename: Nayer
authors.initials: N
authors.lastname: Hussain
authors.forename: Howard
authors.initials: H
authors.lastname: Desmond
authors.forename: James M
authors.initials: JM
authors.lastname: Staddon
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology*; D047390:Casein Kinase II; D002457:Cell Extracts / Q000737:chemistry*; D002458:Cell Fractionation; D008565:Membrane Proteins / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D062793:Occludin; D010766:Phosphorylation; D017354:Point Mutation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013552:Swine
chemical_list: D002457:Cell Extracts; D008565:Membrane Proteins; D062793:Occludin; D011994:Recombinant Proteins; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases