Related Experiment Video

Updated: Jul 29, 2026

Real-time Live Imaging of T-cell Signaling Complex Formation
10:31

Real-time Live Imaging of T-cell Signaling Complex Formation

Published on: June 23, 2013

Cytokine-independent Jak3 activation upon T cell receptor (TCR) stimulation through direct association of Jak3 and

K Tomita1, K Saijo, S Yamasaki

  • 1Department of Molecular Genetics, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8790, Japan.

The Journal of Biological Chemistry
|May 12, 2001
PubMed

Insights

Janus kinase 3 (Jak3) impacts T cell activation and growth signals. This study reveals Jak3

Area of Science:

  • Immunology
  • Cell Signaling
  • Molecular Biology

Background:

  • Janus kinase 3 (Jak3) is crucial for cytokine signaling pathways, particularly those involving the common gamma chain (gammac) in lymphocytes.
  • Its role in T cell activation beyond cytokine signaling remains incompletely understood.

Purpose of the Study:

  • To investigate the role of Jak3 in T cell receptor (TCR) signaling and activation.
  • To elucidate the mechanisms of Jak3 phosphorylation and its association with the TCR complex.

Main Methods:

  • Utilized Jak3-deficient mice to assess T cell function.
  • Investigated Jak3 phosphorylation upon TCR stimulation.
  • Examined Jak3 association with TCR components, including CD3zeta, Lck, and ZAP-70.

Main Results:

  • T cells from Jak3-deficient mice showed impaired cytokine signaling and early activation signals.
  • Jak3 phosphorylation was induced by TCR stimulation, independent of the IL-2 receptor/gammac pathway.
  • Jak3 directly associates with CD3zeta via its JH4 region, distinct from its gammac binding site.
  • Jak3 interaction with TCR complex components Lck and ZAP-70 was observed.

Conclusions:

  • Jak3 plays a significant role in T cell activation, not solely in cytokine-mediated growth.
  • Jak3 acts as a signaling molecule bridging TCR and growth factor signaling pathways.
  • These findings reveal novel cross-talk mechanisms in lymphocyte activation.

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

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity06:16

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity

Published on: December 7, 2019

Related Concept Videos

Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
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...
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...
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...
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
T Cell Activation and Clonal Selection01:22

T Cell Activation and Clonal Selection

T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...