Related Experiment Video

Updated: Aug 10, 2026

Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries
08:49

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

Published on: January 22, 2019

Apoptosis of CTLL-2 cells induced by an immunosuppressant, ISP-I, is caspase-3-like protease-independent

T Yamaji1, S Nakamura, H Takematsu

  • 1Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, and Laboratory of Membrane Biochemistry and Biophysics, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan.

Journal of Biochemistry
|March 29, 2001
PubMed

In our previous study, the sphingosine-like immunosuppressant ISP-1 was shown to induce apoptosis in the mouse cytotoxic T cell line CTLL-2. In this study, we characterized the ISP-1-induced apoptotic pathway. Although caspase-3-like protease activity increases concomitantly with ISP-1-induced apoptosis in CTLL-2 cells, the apoptosis is not inhibited by caspase-3-like protease inhibitors, i.e. DEVD-cho and z-DEVD-fmk. In contrast, sphingosine-induced apoptosis in CTLL-2 cells is caspase-3-like protease-dependent. A caspase inhibitor with broad specificity, z-VAD-fmk, protects cells from apoptosis induced by ISP-1, indicating that ISP-1-induced apoptosis is dependent on caspase(s) other than caspase-3. Overexpression of Bcl-2 or Bcl-xL suppresses the apoptosis induced by ISP-1, although sphingosine-induced apoptosis is not efficiently inhibited by Bcl-2. Finally, ISP-1-induced mitochondrial depolarization, which is thought to be a checkpoint dividing the apoptotic pathway into upstream and downstream stages, is not inhibited by DEVD-cho, but is inhibited by z-VAD-fmk. These data suggest that a pathway dependent on caspase(s) other than caspase-3 is involved upstream of mitochondrial depolarization in ISP-1-induced apoptosis.

More Related Videos

Visualization of Inflammatory Caspases Induced Proximity in Human Monocyte-Derived Macrophages08:41

Visualization of Inflammatory Caspases Induced Proximity in Human Monocyte-Derived Macrophages

Published on: April 6, 2022

Evaluation of Caspase Activation to Assess Innate Immune Cell Death10:23

Evaluation of Caspase Activation to Assess Innate Immune Cell Death

Published on: January 20, 2023

Related Concept Videos

Apoptosis01:30

Apoptosis

Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
Caspases01:24

Caspases

Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
The Extrinsic Apoptotic Pathway01:17

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
The Intrinsic Apoptotic Pathway01:31

The Intrinsic Apoptotic Pathway

Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
Phagocytosis of Apoptotic Cells01:17

Phagocytosis of Apoptotic Cells

Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or  immature dendritic cells. Non-professional phagocytes such as  epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes. 
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Cellular Injury V: Apoptosis and Autophagy01:22

Cellular Injury V: Apoptosis and Autophagy

Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...