Cyclic AMP induces phosphorylation of claudin-5 immunoprecipitates and expression of claudin-5 gene in blood-brain-barrier endothelial cells via protein kinase A-dependent and -independent pathways - PubMed (original) (raw)

Cyclic AMP induces phosphorylation of claudin-5 immunoprecipitates and expression of claudin-5 gene in blood-brain-barrier endothelial cells via protein kinase A-dependent and -independent pathways

Tsutomu Ishizaki et al. Exp Cell Res. 2003.

Abstract

Cyclic AMP (cAMP) promotes functions of tight junctions in endothelial cells, although its target remains unknown. We showed here that cAMP increased gene expression of claudin-5 and decreased that of claudin-1 in porcine blood-brain-barrier endothelial cells via protein kinase A (PKA)-independent and -dependent pathways, respectively. cAMP also enhanced immunoreactivity of claudin-5 along cell borders and in the cytoplasm, reorganized actin filaments, and altered signals of claudin-5, occludin, ZO-1, and ZO-2 along cell boundaries from zipperlike to linear patterns. In contrast, claudin-1 was detected only in the cytoplasm in a dotlike pattern, and its immunolabeling was reduced by cAMP. Interestingly, 31- and 62-kDa claudin-5 immunoprecipitates in the NP-40-soluble and -insoluble fractions, respectively, were highly phosphorylated on threonine residue(s) upon cAMP treatment. All these changes induced by cAMP, except for claudin-5 expression and its signals in the cytoplasm, were reversed by an inhibitor of PKA, H-89. We also demonstrated that cAMP elevated the barrier function of tight junctions in porcine blood-brain-barrier endothelial cells in PKA-dependent and -independent manners. These findings indicate that both PKA-induced phosphorylation of claudin-5 immunoprecipitates and cAMP-dependent but PKA-independent induction of claudin-5 expression could be involved in promotion of tight-junction function in endothelial cells.

PubMed Disclaimer

Similar articles

Cited by

Publication types

MeSH terms

Substances

LinkOut - more resources