Bryostatin-1 enhances barrier function in T84 epithelia through PKC-dependent regulation of tight junction proteins.
Protein kinase C (PKC) is known to regulate epithelial barrier function. However, the effect of specific PKC isozymes, and their mechanism of action, are largely unknown. We determined that the nonphorbol ester PKC agonist bryostatin-1 increased transepithelial electrical resistance (TER), a marker of barrier function, in confluent T84 epithelia. Bryostatin-1, which has been shown to selectively activate PKC-alpha, -epsilon, and -delta (34), was associated with a shift in the subcellular distribution of the tight junction proteins claudin-1 and ZO-2 from a detergent-soluble fraction into a detergent-insoluble fraction. Bryostatin-1 also led to the appearance of a higher-molecular-weight form of occludin previously shown to correspond to protein phosphorylation. These changes were attenuated by the conventional and novel PKC inhibitor Gö-6850 but not the conventional PKC inhibitor Gö-6976 or the PKC-delta inhibitor röttlerin, implicating a novel isozyme, likely PKC-epsilon. The results suggest that enhanced epithelial barrier function induced by bryostatin-1 involves a PKC-epsilon-dependent signaling pathway leading to recruitment of claudin-1 and ZO-2, and phosphorylation of occludin, into the tight junctional complex.
Yoo
James
J
Department of Surgery, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA.
Nichols
Anthony
A
Mammen
Joshua
J
Calvo
Isabel
I
Song
Jaekyung C
JC
Worrell
Roger T
RT
Matlin
Karl
K
Matthews
Jeffrey B
JB
D054713:Bryostatins; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D062445:Claudin-1; D017097:Electric Impedance; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D007783:Lactones / Q000494:pharmacology*; D018942:Macrolides; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism*; D062793:Occludin; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D019108:Tight Junctions / Q000187:drug effects / Q000201:enzymology*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*; D062827:Zonula Occludens-2 Protein
D054713:Bryostatins; C568108:CLDN1 protein, human; D062445:Claudin-1; D004791:Enzyme Inhibitors; D007783:Lactones; D018942:Macrolides; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; C569046:TJP2 protein, human; D062827:Zonula Occludens-2 Protein; C046785:bryostatin 1; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon