B cell receptor-induced cAMP-response element-binding protein activation in B lymphocytes requires novel protein kinase Cdelta.
The cAMP-response element-binding protein (CREB) is activated by phosphorylation on Ser-133 and plays a key role in the proliferative and survival responses of mature B cells to B cell receptor (BCR) signaling. The signal link between the BCR and CREB activation depends on a phorbol ester (phorbol 12-myristate 13-acetate)-sensitive protein kinase C (PKC) activity and not protein kinase A or calmodulin kinase; however, the identity and role of the PKC(s) activity has not been elucidated. We found the novel PKCdelta (nPKCdelta) activator bistratene A is sufficient to induce CREB phosphorylation in murine splenic B cells. The pharmacological inhibitor Gö6976, which targets conventional PKCs and PKCmu, has no effect on CREB phosphorylation, whereas the nPKCdelta inhibitor rottlerin blocks CREB phosphorylation following BCR cross-linking. Bryostatin 1 selectively prevents nPKCdelta depletion by phorbol 12-myristate 13-acetate when coapplied, coincident with protection of BCR-induced CREB phosphorylation. Ectopic expression of a kinase-inactive nPKCdelta blocks BCR-induced CREB phosphorylation in A20 B cells. In addition, BCR-induced CREB phosphorylation is significantly diminished in nPKCdelta-deficient splenic B cells in comparison with wild type mice. Consistent with the essential role for Bruton's tyrosine kinase and phospholipase Cgamma2 in mediating PKC activation, Bruton's tyrosine kinase- and phospholipase Cgamma2-deficient B cells display defective CREB phosphorylation by the BCR. We also found that p90 RSK directly phosphorylates CREB on Ser-133 following BCR cross-linking and is positioned downstream of nPKCdelta. Taken together, these results suggest a model in which BCR engagement leads to the phosphorylation of CREB via a signaling pathway that requires nPKCdelta and p90 RSK in mature B cells.
Blois
Joseph T
JT
Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA.
Mataraza
Jennifer M
JM
Mecklenbraüker
Ingrid
I
Tarakhovsky
Alexander
A
Chiles
Thomas C
TC
D000081:Acetamides / Q000494:pharmacology; D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D001578:Benzopyrans / Q000494:pharmacology; D001665:Binding Sites; D015153:Blotting, Western; D054713:Bryostatins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002227:Carbazoles / Q000494:pharmacology; D002455:Cell Division; D003432:Cross-Linking Reagents / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007783:Lactones / Q000494:pharmacology; D018942:Macrolides; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D008934:Mitogens; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta; D017434:Protein Structure, Tertiary; D011714:Pyrans / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D013141:Spiro Compounds / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate; D013997:Time Factors
D000081:Acetamides; D000098:Acetophenones; D001578:Benzopyrans; D054713:Bryostatins; D002227:Carbazoles; D003432:Cross-Linking Reagents; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D007211:Indoles; D007783:Lactones; D018942:Macrolides; D008934:Mitogens; D020033:Protein Isoforms; D011714:Pyrans; D011947:Receptors, Antigen, B-Cell; D013141:Spiro Compounds; C059975:bistratene A; C081021:Go 6976; C046785:bryostatin 1; D012694:Serine; C085746:rottlerin; C497259:Prkcd protein, mouse; C089212:protein kinase D; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D013755:Tetradecanoylphorbol Acetate