Protein kinase C-theta mediates a selective T cell survival signal via phosphorylation of BAD.
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Villalba M, Bushway P, Altman A
Protein kinase C-theta mediates a selective T cell survival signal via phosphorylation of BAD.
J Immunol. 2001 May 15;166(10):5955-63.
- PubMed ID
- 11342610 [ View in PubMed]
- Abstract
Protein kinase C (PKC)-activating phorbol esters protect T cells from Fas-induced apoptosis. However, the mechanism of this protective effect and the identity of the relevant PKC isoform(s) are poorly understood. Here, we show that PKCtheta plays a selective and important role in this protection. Fas triggering led to a selective caspase-3-dependent cleavage of the enzyme and proteasome-mediated degradation and inactivation of its catalytic fragment. These events preceded the onset of apoptosis. Pharmacological inhibition of PKCtheta promoted Fas-mediated apoptosis in three different types of T cells. Conversely, constitutively active PKCtheta (and, to a lesser degree, PKCepsilon) selectively protected T cells from Fas-induced apoptosis. We provide evidence that the distant Bcl-2 family member, BAD, is a PKCtheta substrate, is phosphorylated by TCR stimulation, and can mediate at least in part the anti-apoptotic effect of PKCtheta.