Occludin phosphorylation: identification of an occludin kinase in brain and cell extracts as CK2

FEBS Lett. 2003 Jun 19;545(2-3):161-6. doi: 10.1016/s0014-5793(03)00525-8.

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.

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Animals
  • Binding Sites
  • Brain / enzymology*
  • Casein Kinase II
  • Cell Extracts / chemistry*
  • Cell Fractionation
  • Membrane Proteins / metabolism*
  • Mutagenesis, Site-Directed
  • Occludin
  • Phosphorylation
  • Point Mutation
  • Protein-Serine-Threonine Kinases / chemistry
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / isolation & purification
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Swine

Substances

  • Cell Extracts
  • Membrane Proteins
  • Occludin
  • Recombinant Proteins
  • Casein Kinase II
  • Protein-Serine-Threonine Kinases