Related Experiment Video

Updated: Oct 7, 2026

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
09:18

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

Published on: December 27, 2016

Protein kinase C-theta mediates a selective T cell survival signal via phosphorylation of BAD

M Villalba1, P Bushway, A Altman

  • 1Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA. villalba@liai.org

Journal of Immunology (Baltimore, Md. : 1950)
|May 9, 2001
PubMed

Insights

Protein kinase C-theta (PKCtheta) protects T cells from Fas-induced apoptosis by preventing enzyme degradation. This finding reveals a key mechanism for T cell survival.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • Protein kinase C (PKC) activators protect T cells from Fas-induced apoptosis.
  • The specific PKC isoforms and mechanisms involved remain unclear.

Purpose of the Study:

  • To elucidate the role of PKC isoforms in T cell protection against Fas-mediated apoptosis.
  • To identify the molecular mechanisms underlying this protective effect.

Main Methods:

  • Investigated the role of PKCtheta using pharmacological inhibitors and constitutively active forms.
  • Analyzed caspase-3 cleavage, proteasomal degradation, and BAD phosphorylation.
  • Utilized three different T cell types for experiments.

Main Results:

  • PKCtheta selectively protects T cells from Fas-induced apoptosis.
  • Fas triggering causes caspase-3-dependent cleavage and proteasomal degradation of PKCtheta.
  • Constitutively active PKCtheta and PKCepsilon conferred protection; PKCtheta inhibition promoted apoptosis.
  • BAD, a Bcl-2 family member, is a PKCtheta substrate phosphorylated by TCR stimulation, mediating anti-apoptotic effects.

Conclusions:

  • PKCtheta plays a critical role in preventing Fas-induced T cell apoptosis.
  • PKCtheta degradation is a key event preceding apoptosis.
  • Phosphorylation of BAD by PKCtheta contributes to T cell survival.

More Related Videos

Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries08:49

Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries

Published on: January 22, 2019

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes09:40

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes

Published on: September 28, 2018

Related Concept Videos

PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...