Casein kinase I epsilon associates with and phosphorylates the tight junction protein occludin.
Occludin is an integral-membrane protein that contributes to tight junction function. We have identified casein kinase I epsilon (CKI epsilon) as a binding partner for the C-terminal cytoplasmic domain of occludin by yeast two-hybrid screening. CKI epsilon phosphorylated occludin and co-localised and co-immunoprecipitated with occludin from human endothelial cells. Amino acids 265-318 of occludin were sufficient for CKI epsilon binding and phosphorylation. Deletion of the C-terminal 48 amino acids of occludin increased CKI epsilon binding and phosphorylation, suggesting that this region inhibits CKI epsilon binding. These data identify CKI epsilon as a novel occludin kinase that may be important for the regulation of occludin.
McKenzie
Jenny A G
JA
Ludwig Institute for Cancer Research, Royal Free and University College, School of Medicine, 91 Riding Street, London WIW 7BS, UK.
Riento
Kirsi
K
Ridley
Anne J
AJ
D048149:Casein Kinase 1 epsilon / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D062793:Occludin; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D017434:Protein Structure, Tertiary / Q000235:genetics; D017384:Sequence Deletion; D019108:Tight Junctions / Q000201:enzymology* / Q000235:genetics; D020798:Two-Hybrid System Techniques
D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D048149:Casein Kinase 1 epsilon