Related Experiment Video

Updated: Aug 8, 2026

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation
08:47

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation

Published on: March 5, 2018

Proteolytic activation of MST/Krs, STE20-related protein kinase, by caspase during apoptosis

K K Lee1, M Murakawa, E Nishida

  • 1Institute for Virus Research, Kyoto University, Japan.

Oncogene
|July 14, 1998
PubMed

Insights

Researchers identified a kinase, MST/Krs, activated by Fas stimulation in human cells. This kinase

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The Fas system is a key model for studying apoptosis (programmed cell death).
  • The caspase cascade is a critical signaling pathway in apoptosis.

Purpose of the Study:

  • To identify and characterize kinases activated by Fas stimulation.
  • To elucidate the activation mechanism of MST/Krs in the context of apoptosis.

Main Methods:

  • Purification of a kinase activated by Fas stimulation in HPB-ALL cells.
  • Partial amino acid sequencing to identify the kinase as MST/Krs (a STE20 family member).
  • Analysis of kinase activation using caspase inhibitors and site-directed mutagenesis.

Main Results:

  • A kinase, identified as MST/Krs, was activated upon Fas stimulation.
  • MST/Krs activation was dependent on proteolytic cleavage, inhibited by Z-VAD-FK.
  • A specific mutation at a putative caspase cleavage site rendered MST/Krs resistant to activation.

Conclusions:

  • Proteolytic cleavage is a mechanism for MST/Krs activation.
  • MST/Krs activation plays a role in the Fas-mediated apoptotic pathway.
  • This study reveals a novel link between caspase activity and MST/Krs function in apoptosis.

More Related Videos

Exploring Caspase Mutations and Post-Translational Modification by Molecular Modeling Approaches05:56

Exploring Caspase Mutations and Post-Translational Modification by Molecular Modeling Approaches

Published on: October 13, 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...
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...
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...