The epsilon isoform of protein kinase C is involved in regulation of the LTD(4)-induced calcium signal in human intestinal epithelial cells.
We investigated the potential roles of specific isoforms of protein kinase C (PKC) in the regulation of leukotriene D(4)-induced Ca(2+) signaling in the intestinal epithelial cell line Int 407. RT-PCR and Western blot analysis revealed that these cells express the PKC isoforms alpha, betaII, delta, epsilon, zeta, and mu, but not betaI, gamma, eta, or theta;. The inflammatory mediator leukotriene D(4) (LTD(4)) caused the TPA-sensitive PKC isoforms alpha, delta, and epsilon, but not betaII, to rapidly translocate to a membrane-enriched fraction. The PKC inhibitor GF109203X at 30 microM but not 2 microM significantly impaired the LTD(4)-induced Ca(2+) signal, indicating that the response involves a novel PKC isoform, such as delta or epsilon, but not alpha. LTD(4)-induced Ca(2+) signaling was significantly suppressed in cells pretreated with TPA for 15 min and was abolished when the pretreatment was prolonged to 2 h. Immunoblot analysis revealed that the reduction in the LTD(4)-induced calcium signal coincided with a reduction in the cellular content of PKCepsilon and, to a limited extent, PKCdelta. LTD(4)-induced Ca(2+) signaling was also markedly suppressed by microinjection of antibodies against PKCepsilon but not PKCdelta. These data suggest that PKCepsilon plays a unique role in regulation of the LTD(4)-dependent Ca(2+) signal in intestinal epithelial cells.
Thodeti
C K
CK
Division of Experimental Pathology, Lund University, U-MAS, Malmö, SE-205 02, Sweden.
Nielsen
C K
CK
Paruchuri
S
S
Larsson
C
C
Sjölander
A
A
D000906:Antibodies / Q000008:administration & dosage; D015153:Blotting, Western; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002458:Cell Fractionation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017998:Leukotriene D4 / Q000378:metabolism* / Q000494:pharmacology; D008845:Microinjections; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D021381:Protein Transport / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000906:Antibodies; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D017998:Leukotriene D4; C497258:PRKCD protein, human; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D013755:Tetradecanoylphorbol Acetate