Negative-feedback regulation of CD28 costimulation by a novel mitogen-activated protein kinase phosphatase, MKP6.
TCR and CD28 costimulatory receptor-cooperative induction of T cell IL-2 secretion is dependent upon activation of mitogen-activated protein (MAP) kinases. Using yeast-hybrid technology, we cloned a novel CD28 cytoplasmic tail (CD28 CYT) interacting protein, MAP kinase phosphatase-6 (MKP6), which we demonstrate inactivates MAP kinases. Several lines of evidence indicate that MKP6 plays an important functional role in CD28 costimulatory signaling. First, in human peripheral blood T cells (PBT), expression of MKP6 is strongly up-regulated by CD28 costimulation. Second, transfer of dominant-negative MKP6 to PBT with the use of retroviruses primes PBT for the secretion of substantially larger quantities of IL-2, specifically in response to CD28 costimulation. A similar enhancement of IL-2 secretion is observed neither in response to TCR plus CD2 costimulatory receptor engagement nor in response to other mitogenic stimuli such as phorbol ester and ionomycin. Furthermore, this hypersensitivity to CD28 costimulation is associated with CD28-mediated hyperactivation of MAP kinases. Third, a retroviral transduced chimeric receptor with a CD28 CYT that is specifically unable to bind MKP6 costimulates considerably larger quantities of IL-2 from PBT than a similar transduced chimeric receptor that contains a wild-type CD28 CYT. Taken together, these results suggest that MKP6 functions as a novel negative-feedback regulator of CD28 costimulatory signaling that controls the activation of MAP kinases.
Marti
F
F
T Cell Signal Transduction Laboratory, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, NY 10021, USA.
Krause
A
A
Post
N H
NH
Lyddane
C
C
Dupont
B
B
Sadelain
M
M
King
P D
PD
D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D018106:CD28 Antigens / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D003593:Cytoplasm / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology*; D054637:Dual-Specificity Phosphatases; D004789:Enzyme Activation / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005333:Fetus; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D054639:Mitogen-Activated Protein Kinase Phosphatases; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics / Q000276:immunology; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010749:Phosphoprotein Phosphatases; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012190:Retroviridae / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology / Q000378:metabolism; D014161:Transduction, Genetic; D020798:Two-Hybrid System Techniques; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
D018106:CD28 Antigens; D004791:Enzyme Inhibitors; D007376:Interleukin-2; D010446:Peptide Fragments; D014443:Tyrosine; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D054639:Mitogen-Activated Protein Kinase Phosphatases; D010749:Phosphoprotein Phosphatases; C498843:DUSP14 protein, human; D054637:Dual-Specificity Phosphatases; D017027:Protein Tyrosine Phosphatases